TM 55-1520-228-BD TECHNICAL MANUAL OPERATORS, …tm 55-1520-228-bd technical manual operators, aviation unit, and aviation intermediate maintenance for hellcopter, observation oh-58a

T M 5 5 - 1 5 2 0 - 2 2 8 - B D

TECHNICAL MANUAL

OPERATORS, AVIATION UNIT,AND AVIATION

INTERMEDIATE MAINTENANCE

F O R

H E L l C O P T E R ,

O B S E R V A T I O N

O H - 5 8 A & O H - 5 8 C

ITEM NSN

INSIDE FRONT COVER

This publication supersedesTM 55-1520-228-BD dated17 August 1990.

CHAPTER 1. GENERAL INFORMATION

CHAPTER 2. ASSESSING BATTLEFIELD DAMAGE

CHAPTER 3. GENERAL REPAIR

CHAPTER 4. AIRFRAME

CHAPTER 5. ALIGHTING GEAR

CHAPTER 6. POWER PLANT

CHAPTER 7. ROTORS

CHAPTER 8. DRIVE TRAIN SYSTEM

CHAPTER 9. HYDRAULIC SYSTEM

CHAPTER 10: INSTRUMENT SYSTEMS

CHAPTER 11. ELECTRICAL SYSTEM

CHAPTER 12. FUEL SYSTEM

CHAPTER 13. FLIGHT CONTROLS

CHAPTER 14. UTILITY SYSTEM

CHAPTER 15. ENVIRONMENTAL CONTROL SYSTEM

CHAPTER 16. MISSION EQUIPMENT

CHAPTER 17. EMERGENCY EQUIPMENT

APPENDIX A . REFERENCES

APPENDIX B. SPECIAL OR FABRICATED TOOLS

APPENDIX C. EXPENDABLE/DURABLE SUPPLIES & MATERIALSAPPENDIX D. SUBSTITUTE MATERIALS/PARTS

APPENDIX E. BDAR TRAINING PROCEDURES

H E A D Q U A R T E R S , D E P A R T M E N T O F T H E A R M Y

4 J a n u a r y 1 9 9 1

APPENDIX F. AVIONICS CONFIGURATIONS

TM 55-1520-228-BD

BDAR FIXES SHALL BE USED ONLY IN COMBATAT THE DISCRETION OF THE COMMANDER

AND SHALL BE REPAIRED BY STANDARD MAINTENANCE PROCEDURESAS SOON AS PRACTICABLE AFTER THE MISSION IS COMPLETED.

BDAR TECHNIQUES IN THIS MANUAL PERTAIN to the following helicopters:

OH-58A Helicopter, Observation NSN 1520-00-169-7137

OH-58C Helicopter, Observation NSN 1520-01-020-4216

TM 55-1520-228-BD

WARNING DATA

Personnel performing operations, procedures, and practices which are included orimplied in this technical manual shall observe the general following warnings.Disregard of these warnings can cause serious injury or death.

WARNINGS

FLIGHT SAFETY

The standards contained herein allow aircraft to be flown with battle damagesubstantially in excess of peacetime limits. Under no circumstances shall thismanual be used entirely or in part for peacetime maintenance of the aircraft.Assessment of aircraft battle damage requires extreme care and diligence and strictadherence to the instructions and standards contained in this manual. If at anystage of damage assessment the assessor believes that oversights or errors havebeen made, the assessment shall be stopped at that point and repeated from thebeginning. Under no circumstances shall the requirements of this manual be waivedor circumvented without the express approval of the commander or his designatedrepresentative.

EXPLOSIVES

Battle damaged areas should be inspected for unexploded ordnance before attempting repairs. Disposal of unexploded ordnance should be accomplished by qualifiedpersonnel.

ARMAMENT

Loaded weapons or weapons being loaded or unloaded shall be pointed in a directionwhich offers the least exposure to personnel or property in the event of accidentalfiring. Personnel shall remain clear of hazardous area.

CLEANING SOLVENTS

Cleaning solvents may be flammable and toxic. Use only in well-ventilated areas.Avoid inhalation of vapor and skin contact. Do not use solvents near open flame orin areas where very high temperatures prevail. Solvent flash point must not be lessthan 100°F.

COMPRESSED AIR

Compressed air can blow dust into eyes. Wear eye protection. Do not exceed 30 psigair pressure.

ELECTROLYTE

Battery Electrolyte (Potassium Hydroxide) is corrosive. Wear rubber gloves, apron,and face shield when handling leaking batteries. If potassium hydroxide is spilledon clothing or other material, wash immediately with clean water. If spilled onpersonnel, immediately start flushing the affected area with clean water. Continuewashing until medical assistance arrives.

a

TM 55-1520-228-BD

HIGH VOLTAGE

is used in this equipment.

DEATH ON CONTACTmay result if personnel fail to observe safety precautions.

Never work on electronic equipment unless there is another person nearby who isfamiliar with the operation and hazards of the equipment and who is competent inadministering first aid. When the technician is aided by operators, he must warnthem about dangerous areas.

Whenever the nature of the operation permits, keep one hand away from the equipmentas to reduce the hazard of current flowing through vital organs of the body.

Do not be mislead by the term “low voltage.” Potentials as low as 50 volts maycause death under adverse conditions. For Artificial Respiration, refer to FM 21-11.

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TM 55-1520-228-BD

E X T E R N A L S T O R E S

P r i o r t o a n y h e l i c o p t e r m a i n t e n a n c e f u n c t i o n s t h a t r e q u i r e e x t e r n a l s t o r e s b er e m o v e d , J E T T I S O N c a r t r i d g e s h a l l b e r e m o v e d . T o p r e v e n t i n j u r y t o p e r s o n n e la n d d a m a g e t o e q u i p m e n t , r e m o v e j e t t i s o n c a r t r i d g e s f r o m s t o r e s e j e c t i o n d e v i c ep r i o r t o p l a c i n g h e l i c o p t e r i n a h a n g a r .

A l l g r o u n d s a f e t y p i n s m u s t b e r e m o v e d b e f o r e f l i g h t . F a i l u r e t o d o s o w i l l p r e v e n te m e r g e n c y j e t t i s o n o f s t o r e s .

FIRE EXTINGUISHER

E x p o s u r e t o h i g h c o n c e n t r a t i o n s o f m o n o b r o m o t r i f l u o r o m e t h a n e ( C F3 B R ) e x t i n g u i s h i n ga g e n t o r d e c o m p o s i t i o n p r o d u c t s s h o u l d b e a v o i d e d . T h e l i q u i d s h o u l d n o t b e a l l o w e dt o c o m e i n t o c o n t a c t w i t h t h e s k i n , a s i t m a y c a u s e f r o s t b i t e o r l o w t e m p e r a t u r eb u r n s .

FUELING AND FUEL REPAIRS

W h e n r e f u e l i n g h e l i c o p t e r , t h e r e f u e l i n g v e h i c l e m u s t b e p a r k e d a m i n i m u m o f 2 0 f e e tf r o m t h e h e l i c o p t e r . B e f o r e s t a r t i n g t h e f u e l i n g o p e r a t i o n , a l w a y s i n s e r t f u e l i n gn o z z l e g r o u n d i n g c a b l e o f f u e l t r u c k i n t o G R O U N D H E R E r e c e p t a c l e . R e f e r t o F M1 0 - 6 8 . W h e n d e f u e l i n g , t u r n o f f a l l e l e c t r i c a l s w i t c h e s a n d d i s c o n n e c t e x t e r n a lp o w e r f r o m t h e h e l i c o p t e r . T h e h e l i c o p t e r m u s t b e e l e c t r i c a l l y g r o u n d e d p r i o r t od e f u e l i n g .

F u e l l i n e a n d t a n k r e p a i r s o f t e n i n v o l v e h a n d l i n g o f h i g h l y f l a m m a b l e m a t e r i a l .M i s h a n d l i n g c a n r e s u l t i n s e r i o u s i n j u r y o r d e a t h .

GROUNDING HELICOPTER

T h e h e l i c o p t e r s h o u l d b e e l e c t r i c a l l y g r o u n d e d w h e n p a r k e d t o d i s s i p a t e s t a t i ce l e c t r i c i t y . T u r n o f f a l l p o w e r s w i t c h e s b e f o r e m a k i n g e l e c t r i c a l c o n n e c t i o n s o rd i s c o n n e c t i o n s .

HIGH PRESSURE

E x t r e m e l y h i g h p r e s s u r e c a n o c c u r d u r i n g a n d a f t e r o p e r a t i o n o f c e r t a i n e q u i p m e n t .I f t h i s p r e s s u r e i s n o t r e l i e v e d b e f o r e w o r k i n g o n t h i s e q u i p m e n t , s e r i o u s i n j u r y o rd e a t h m a y o c c u r . B e s u r e t o o p e n a l l d r a i n s a n d v e n t s b e f o r e b e g i n n i n g d i s a s s e m b l y .

HYDRAULIC FLUID

P r o l o n g e d c o n t a c t w i t h l i q u i d o r m i s t c a n i r r i t a t e e y e s a n d s k i n . W e a r r u b b e rg l o v e s w h e n h a n d l i n g l i q u i d . A f t e r c o n t a c t w i t h s k i n , i n m m e d i a t e l y w a s h c o n t a c t e da r e a w i t h s o a p a n d w a t e r . I f l i q u i d c o n t a c t s e y e s , f l u s h i m m e d i a t e l y w i t h c l e a rw a t e r . I f l i q u i d i s s w a l l o w e d , d o n o t i n d u c e v o m i t i n g , g e t i m m e d i a t e m e d i c a l a t t e n -t i o n . I f p r o l o n g e d e x p o s u r e w i t h m i s t i s l i k e l y , w e a r a n a p p r o p r i a t e r e s p i r a t o r .W h e n f l u i d i s d e c o m p o s e d b y h e a t i n g , t o x i c g a s e s a r e r e l e a s e d .

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TM 55-1520-228-BD

LIFTING

Lifting or moving heavy equipment incorrectly can cause serious injury. Do not tryto lift or move more than 50 pounds by yourself. Bend legs while lifting. DO notsupport heavy weight with your back. Always use assistants during lifting opera-tions. Use guide ropes to move hanging assemblies. Lack of attention or being inan improper position during lifting operations can result in serious injury. Payclose attention to movements of assemblies being lifted. Do not stand under liftedassembly or in a position where you could be pinned against another object. Watchyour footing.

NOISE

Sound pressure levels in and around this aircraft during operating conditions exceedthe Surgeon General’s hearing conservation criteria, as defined in TB MED 501.Hearing protection devices such as aviator helmet or ear plugs are required to beworn.

RADIOACTIVE MATERIALS

Self-luminous dials and ignition units may contain radioactive materials. If suchan instrument or unit is broken or becomes unsealed, avoid personal contact. Useforceps or gloves made of rubber or polyethylene to pick up contaminated material.Place materials and gloves in a plastic bag. Seal bag and dispose of it as radio-active waste in accordance with AR 708-1 and TM 3-261 (Refer to TB 43-0108). Repairshall conform to requirements in AR 385-11.

SANDING DUST

Sanding on reinforced laminated glass produces fine dust that may cause skinand lung irritations. Observe necessary protective measures.

STARTING HELICOPTER

Starting and operation of the helicopter will be performed only by authorizedpersonnel.

TOXIC POISONS

Turbine fuels, lubricating oils, and adhesives contain additives which are poisonousand readily absorbed through the skin. Do not allow them to remain on skin longerthan necessary. Wear protective equipment.

d

TM 55-1520-228-BD C 1 CHANGE HEADQUARTERS

DEPARTMENT OF THE ARMY NO. 1 WASHINGTON, D.C., 1 September 2005

TECHNICAL MANUAL

OPERATORS, AVIATION UNIT, AND AVIATION INTERMEDIATE MAINTENANCE

BATTLEFIELD DAMAGE ASSESSMENT AND REPAIR

FOR HELICOPTER, OBSERVATION OH-58A & OH-58C

DISTRIBUTION STATEMENT A: Approved for public release; distribution is unlimited. TM 55-1520-228-BD, dated 4 January 1991, is changed as follows: 1. Remove and insert pages as indicated below. New or changed text material is indicated by a vertical bar in the margin. An illustration change is indicated by a miniature pointing hand. Remove Pages Insert Pages ------------- A/(B blank)

i and ii i and ii 1-5 and 1-6 1-5 and 1-6 2. Retain this sheet in front of manual for reference purposes. DISTRIBUTION: To be distributed in accordance with Initial Distribution Number (IDN) 311704, requirements for TM 55-1520-228-BD.

By Order of the Secretary of the Army:

PETER J. SCHOOMAKER General, United States Army

Chief of Staff Official:

SANDRA R. RILEY Administrative Assistant to the

Secretary of the Army0518801

TM 55-1520-228-BD

*Zero in this column indicates an original page.

LIST OF EFFECTIVE PAGES Insert latest changed pages. Dispose of superseded pages in accordance with regulations. NOTE: On a changed page, the portion of the text affected by the latest change is indicated by a vertical line, or other change symbol, in the outer margin of the page. Changes to illustrations are indicated by miniature pointing hands. Changes to wiring diagrams are indicated by shaded areas. Dates of issue for original and changed pages are: Original ………… 4 January 1991 Change 1……… 1 September 2005 TOTAL NUMBER OF PAGES IN THIS PUBLICATION IS 762. CONSISTING OF THE FOLLOWING: Page *Change Page *Change No. No. No. No. Cover.....................................................0 A through d............................................0 i..............................................................1 ii through ix............................................0 x blank ...................................................0 1-1 through 1-5......................................0 1-6 .........................................................1 1-7 through 1-11....................................0 1-12 blank..............................................0 2-1 through 2-9......................................0 2-10 blank..............................................0 3-1 .........................................................0 3-2 blank................................................0 4-1 through 4-70....................................0 5-1 through 5-6......................................0 6-1 through 6-12....................................0 7-1 through 7-8......................................0 8-1 through 8-12....................................0 9-1 through 9-17....................................0 9-18 blank ............................................0 10-1 .......................................................0 10-2 blank..............................................0 11-1 through 11-49................................0 11-50 blank ...........................................0 12-1 through 12-9..................................0 12-10 blank ...........................................0 13-1 through 13-14................................0 14-1 and 14-2........................................0 15-1 through 15-11................................0 15-12 blank ...........................................0 16-1 .......................................................0 16-2 blank..............................................0 17-1 .......................................................0 17-2 blank..............................................0 A-1.........................................................0 A-2 blank ...............................................0 B-1 and B-2 ...........................................0 C-1 through C-4 ....................................0

D-1 through D-11 .................................. 0 D-12 blank............................................. 0 E-1 and E-2........................................... 0 F-1 through F-22................................... 0 Index-1 through index-5........................ 0 Index-6 blank ........................................ 0 Glos-1 through Glos-8 .......................... 0

Change 1 A/(B blank)

TM 55-1520-228-BD

Technical Manual

No. 55-1520-228-BD

HEADQUARTERSDEPARTMENT OF THE ARMY

TECHNICAL MANUALOPERATORS, AVIATION UNIT, AND AVIATION INTERMEDIATE MAINTENANCE

BATTLEFIELD DAMAGE ASSESSMENT AND REPAIRFOR HELICOPTER, OBSERVATION OH-58A & OH-58C

REPORTING ERRORS AND RECOMMENDING IMPROVEMENTS

You can help improve this manual. If you find any mistakes, or if you know of a way to improve these procedures, please let usknow. Mail your letter or DA Form 2028 (Recommended Changes to Publications and Blank Forms) located in the back of thismanual, directly to: Commander, U.S. Army Aviation and Missile Command, ATTN: AMSAM-MMC-MA-NP, Redstone Arsenal,

TABLE OF CONTENTS

CHAPTER 1 -

Section I.Section II.

HOW TO USE THIS MANUAL

GENERAL INFORMATION

Introduction . . . . . . . . . . . . . . . . . . . . . . . .Standards and Practices. . . . . . . . . . . . . . . . . . .

Section III. Tasks and Responsibilities . . . . . . . . . . . . . . . . .

CHAPTER 2 - ASSESSING BATTLEFIELD DAMAGE

Section I. Introduction. . . . . . . . . . . . . . . . . . . . . . . .Section II. General Fault Assessment Table . . . . . . . . . . . . . . .

CHAPTER 3 - GENERAL REPAIRS . . . . . . . . . . . . . . . . . . . . . . . .

CHAPTER 4 - AIRFRAME

Section I. Introduction. . . . . . . . . . . . . . . . . . . . . . . .Section II. Expedient Structural Repairs . . . . . . . . . . . . . . . .

CHAPTER 5 - ALIGHTING GEAR

Section I. Introduction. . . . . . . . . . . . . . . . . . . . . . . .Section II. Skid Tube. . . . . . . . . . . . . . . . . . . . . . . . . . Section III. Skid Damage. . . . . . . . . . . . . . . . . . . . . . . . .

CHAPTER 6 - POWER PLANT INSTALLATION

Section I. Introduction. . . . . . . . . . . . . . . . . . . . . . . .Section II. Component Expedient Fixes. . . . . . . . . . . . . . . . . .

Page

viii

1-11-31-5

2-12-3

3-1

4-14-49

5-15-15-4

6-16-1

Change 1 i

the World Wide Web. Our fax number is: DSN 788-6546 or Commercial 256-842-6546. Our e-mail address is AL 35898-5000. A reply will be furnished to you. You may also provide DA Form 2028 information to AMCOM via e-mail, fax, or

[email protected]. Instructions for sending an electronic 2028 may be found at the back of this manual immediatelypreceding the hard copy 2028. For the World Wide Web use: https://amcom2028.redstone.army.mil.

Distribution Statement: Approved for public release; distribution is unlimited.

WASHINGTON, D.C., 4 January 1991

TM 55-1520-228-BD

TABLE OF CONTENTS (Cont)

Page

CHAPTER 7 - ROTORS

Section I. Introduction. . . . . . . . . . . . . . . . . . . Section II. Repairs . . . . . . . . . . . . . . . . .

CHAPTER 8 - DRIVE TRAIN SYSTEM

Section I. Introduction. . . . . . . . . . . . . . . . . . . . .Section II. Repair. . . . . . . . . . . . . . . . . . . . . . . .

CHAPTER 9 - HYDRAULIC

Section I. Introduction. . . . . . . . . . . . . . . . . . . . .Section II. Lines and Hoses. . . . . . . . . . . . . . . . . . .Section III. Seals, Packings, and Gaskets . . . . . . . . . . . . .

CHAPTER 10 - INSTRUMENTS

Section I. Introduction. . . . . . . . . . . . . . . . . . . . .Section II. Instrument Replacement . . . . . . . . . . . . . .

CHAPTER 11 - ELECTRICAL AND AVIONICS SYSTEM

Section I. Introduction. . . . . . . . . . . . . . . . . . . . .Section II. Electrical and Avionics Wiring Damage. . . . . . . .

CHAPTER 12 - FUEL SYSTEMS

Section I. Introduction. . . . . . . . . . . . . . . . . . . . .Section II. Lines and Hoses. . . . . . . . . . . . . . . . . . .Section III. Fuel Cell Damage. . . . . . . . . . . . . . . .

CHAPTER 13 - FLIGHT CONTROLS SYSTEM

Section I. Introduction. . . . . . . . . . . . . . . . . . . . .Section II. Flight Control Tubes. . . . . . . . . . . . . . . . .

CHAPTER 14 - UTILITY SYSTEMS

Section I. Introduction. . . . . . . . . . . . . . . . . . . .Section II. De-Ice Valve or Control. . . . . . . . . . . . . . .

CHAPTER 15 - ENVIRONMENTAL CONTROL SYSTEM

Section I. Introduction, . . . . . . . . . . . . . . . . . . . .Section II. Rigid Plastic Ventilation Duct . . . . . . . . . . .Section III. Bleed Air Line Damage. . . . . . . . . . . . . . .

7-17-1

8-18-1

9-19-19-14

10-110-6

11-111-6

12-112-112-4

13-113-1

14-114-1

15-115-115-9

ii

CHAPTER 16 -

CHAPTER 17 -

CHAPTER 18 -

Section I.Section II.

CHAPTER 19 -

APPENDIX A -APPENDIX B -APPENDIX C -APPENDIX D -APPENDIX E -APPENDIX F -GLOSSARY . .INDEX . . .

Figure

1-11-21-34-14-24-34-44-54-64-74-84-94-104-114-124-134-144-154-164-174-184-194-204-214-22

TM 55-1520-228-BD

TABLE OF CONTENTS (Cont)

Page

HOIST AND WINCHES. . . . . . . . . . . . . . . . . . . . . . 16-1

AUXILIARY POWER PLANT . . . . . . . . . . . . . . . . . . . . 17-1

MISSION EQUIPMENT . . . . . . . . . . . . . . . . . . . . . .

Introduction. . . . . . . . . . . . . . . . . . . . . . . . 18-1Gun and Mount Assembly . . . . . . . . . . . . . . . . . . . 18-1

EMERGENCY EQUIPMENT. . . . . . . . . . . . . . . . . . . . . 19-1

REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . . . . A-1SPECIAL OR FABRICATED TOOLS . . . . . . . . . . . . . . . . . . . . . . . B-1EXPENDABLE/DURABLE SUPPLIES AND MATERIALS . . . . . . . . . . C-1SUBSTITUTE MATERIALS/PARTS. . . . . . . . . . . . . . . . . . D-1BDAR TRAINING PROCEDURES. . . . . . . . . . . . . . . . . . . E-1AVIONICS CONFIGURATION. . . . . . . . . . . . . . . . . . . . F-1✎ . . . . ✎ .. . .... ... . . . . . ... GLOS-1. . . . . . . . .... . ... ... .. INDEX-1

LIST OF ILLUSTRATIONS

Title

DA Form 2408-13. . . . . . . . . . . . . . . . . . . . . . .DA Form 2408-18. . . . . . . . . . . . . . . . . . . . . . .Damage Assessment Markings (Sheet 1 of 3). . . . . . . . .Aircraft Sections. . . . . . . . . . . . . . . . . . . . . .DA Form 2404. . . . . . . . . . . . . . . . . . . . . . . .Evaluating Damage to Angles, Channels, and Z-Angles. . . . .Damaged Cross Section. . . . . . . . . . . . . . . . . . . .Measuring Skin Panel Damage. . . . . . . . . . . . . . . . .Measuring Damage in Webs and Panels. . . . . . . . . . . . .Measuring Damage in Honeycomb Sandwich Panels. . . . . . . .OH-58 Helicopter. . . . . . . . . . . . . . . . . . . . . .Airframe Reference Lines. . . . . . . . . . . . . . . . . .Cockpit. . . . . . . . . . . . . . . . . . . . . . . . . . .Fuselage Pylon Support Structure (Sheet 1 of 5). . . . . . .Upper and Lower Shell Structure. . . . . . . . . . . . . . .Aft Fuselage Structure.. . . . . . . . . . . . . . . . . .Tail Boom . . . . . . . . . . . . . . . . . . . . . . . . .Cowling and Firewalls . . . . . . . . . . . . . . . . . . . .Typical Former Repair (Sheet 1 of 2) . . . . . . . . . . . .Cutout in Damage Skin. . . . . . . . . . . . . . . . . . . .Patch Plate. . . . . . . . . . . . . . . . . . . . . . . . .Typical Patch Plate Repair . . . . . . . . . . . . . . . . .Expedient Cap/Longeron Repair. . . . . . . . . . . . . . . .Repair of Damage Bulkhead Flange . . . . . . . . . . . . . .Typical Combination Repair (Sheet 1 of 2). . . . . . . . . .

Page

1-71-81-94-34-64-84-94-104-114-134-174-184-194-204-254-264-274-284-524-544-554-564-584-604-61

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LIST OF ILLUSTRATIONS (Cont)

Figure Title Page

4-23

4-24

4-25

4-264-274-28

4-294-305-15-25-35-45-56-16-26-36-46-56-66-76-87-17-27-37-47-58-18-28-39-19-29-39-49-59-69-79-8,9-99-109-119-12

Damaged Honeycomb Core Panel, Small Damage to One Skinand Core... . . . . . . . . . . . . . . . . . . . . . . .Damaged Honeycomb Core Panel, 2-8 Inch Damage - One Skinand Core. . . . . . . . . . . . . . . . . . . . . . . . .Repaired Honeycomb Core Panel, 2-8 Inch Damage - One Skinand Core. . . . . . . . . . . . . . . . . . . . . . . . . .Damaged Repair, Accessible One Side Only . . . . . . . . . .Patch Plates, One Side Accessible Repair . . . . . . . . . .Repair of Honeycomb Core Panel, Damage Over 8 Inches - BothSkins and Core. . . . . . . . . . . . . . . . . . . . . . .Fracture Lacing with Safety Wire . . . . . . . . . . . . . .Tail Boom Skin Damage. . . . . . . . . . . . . . . . . . . .Landing Gear and Support Installation. . . . . . . . . . . .Skid Tube Damage Zones. . . . . . . . . . . . . . . . . . .Skid Repair. . . . . . . . . . . . . . . . . . . . . . . . .Clamp Repair. . . . . . . . . . . . . . . . . . . . . . . .Fabricated Clamp. . . . . . . . . . . . . . . . . . . . . .T63 Series Engine. . . . . . . . . . . . . . . . . . . . . .Blocking Plate Installation. . . . . . . . . . . . . . . . .Double-Check Valve System, Possible Alternatives . . . . . .Wood Plug. . . . . . . . . . . . . . . . . . . . . . . . . .Sealant for Small Holes... . . . . . . . . . . . . . . . .Repair Using Screw, Washer and Gasket. . . . . . . . . . . .Hose Assembly, Sealant, Nut, and Bolt. . . . . . . . . . . .Sheet Metal with Sealant and/or Cherry Rivets. . . . . . . .Main Rotor System. . . . . . . . . . . . . . . . . . . . . .Tail Rotor System. . . . . . . . . . . . . . . . . . . . . .Rotor Blades, Damage Sensitive Areas . . . . . . . . . . . .Rotor Blade Repair, Application of Tape. . . . . . . . . . .Repair Areas - Main Rotor B1ades . . . . . . . . . . . . . .Drive Train System (Sheet 1 of 4). . . . . . . . . . . . .External Components - Transmission Oil System. . . . . . . .Flex Duct Repair (Sheet 1 of 2) . . . . . . . . . . . . . . .Hydraulic System. . . . . . . . . . . . . . . . . . . . . .Hydraulic System Schematic . . . . . . . . . . . . . . . . .Two-Part Fitting. . . . . . . . . . . . . . . . . . . . . .Four-Part Fitting. . . . . . . . . . . . . . . . . . . . . .Using Tube Cutter. . . . . . . . . . . . . . . . . . . . . .Properly Burred Tubing . . . . . . . . . . . . . . . . . . .Damaged Tube Section-Straight Tube . . . . . . . . . . . . .Splice Repair Assembly . . . . . . . . . . . . . . . . . . .Repair Fitting and Tube Installation . . . . . . . . . . . .Damaged Tube Section-Complex Bends . . . . . . . . . . . . .Splice Adapter Assembly Installation . . . . . . . . . . . .Installation of Socket and Sleeve. . . . . . . . . . . . . .

4-64

4-64

4-644-664-66

4-674-694-705-25-25-55-55-66-26-56-76-86-96-96-106-127-27-37-57-77-88-28-88-99-29-39-49-59-59-79-79-89-89-109-109-12

iv

TM 55-1520-228-BD

Figure

9-139-1411-111-211-311-411-511-611-711-811-911-1011-1111-1211-1311-1411-1511-1611-1711-1811-1911-2011-2111-2211-2311-2411-2511-2611-2711-2811-2911-3011-3111-3211-3311-3411-3511-3611-3711-3811-3911-4011-4111-4211-4311-4411-45


Title

Assembly of MS Fitting . . . . . . . . . . . . . . . . . . .Union Connection. . . . . . . . . . . . . . . . . . . . . .Circuit Identification . . . . . . . . . . . . . . . . . . .Crimp Splice. . . . . . . . . . . . . . . . . . . . . . . .Splicing with Terminal Lug Barrel. . . . . . . . . . . . . .Twist Wire Splice . . . . . . . . . . . . . . . . . . . . .Replacement Section; Twist Wire Splice . . . . . . . . . . .Metal Casing Splice Splice. . . . . . . . . . . . . . . . .Bolted Terminal Lug Repair of Large Wires. . . . . . . . . .Replacement Section; Terminal Lug Repair . . . . . . . . . .Ram Wire Repair . . . . . . . . . . . . . . . . . . . . . .Heat-Shrinkable Tape . . . . . . . . . . . . . . . . . . . .Insulation Repair with Sleeving. . . . . . . . . . . . . . .Shielded Cable Repair Preparation. . . . . . . . . . . . . .Shielded Cable Splice Preparation. . . . . . . . . . . . . .Shielded Cable Spliced . . . . . . . . . . . . . . . . . . .Shielded Cable Repair... . . . . . . . . . . . . . . . . .Pigtail Method Repair . . . . . . . . . . . . . . . . . . .Substitute Shielded Braid Repair . . . . . . . . . . . . . .Shield Terminator Repair Preparation . . . . . . . . . . . .Shield Terminator Repair.. . . . . . . . . . . . . . . . .Nickel-Plated Shield Terminator Preparation. . . . . . . . .Nickel-Plated Shield Terminator Repair . . . . . . . . . . .Terminal Lug Repair. . . . . . . . . . . . . . . . . . . . .Self-Clinching Cable Strap . . . . . . . . . . . . . . . . .Self-Clinching Cable Strap and Tool. . . . . . . . . . . . .Tie Tape Repair Procedure. . . . . . . . . . . . . . . . . .Coax Splice Preparation.. . . . . . . . . . . . . . . . . .Coax Splice Inner Sleeve. . . . . . . . . . . . . . . . . .Coax Splice Shield Sleeve. . . . . . . . . . . . . . . . . .Coax Splice with Tubing Sleeve . . . . . . . . . . . . . . .Coax Splice with Cable Braid over Barrier Sleeves. . . . . .Coax Repair with Cable Braid over Barrier Sleeve . . . . . .Component Bypass. . . . . . . . . . . . . . . . . . . . . .Connector Pin and Socket.. . . . . . . . . . . . . . . . .Damaged Connector and Pigtail. . . . . . . . . . . . . . . .Circuit Breakers, . . . . . . . . . . . . . . . . . . . . .Typical Circuit Breaker Connection . . . . . . . . . . . . .Construction of Fuse Link. . . . . . . . . . . . . . . . . .Splicing Bus Bars. . . . . . . . . . . . . . . . . . . . . .Lengthening Bus Bars... . . . . . . . . . . . . . . . . .Battery, Storage BB-476/A, Cell Layout . . . . . . . . . . .Block Diagram Power Relay, Check and Test. . . . . . . . . .Location of Power Relays. . . . . . . . . . . . . . . . . .Block Diagram, Typical Power Relays. . . . . . . . . . . . .Jumper Wire Fabrication.. . . . . . . . . . . . . . . . . .Frequency vs. Wave length. . . . . . . . . . . . . . . . .

Page

9-129-1311-211-811-1011-1111-1211-1211-1411-1411-1411-1611-1611-1711-1811-1911-2011-2211-2311-24ll-2511-2511-2511-2611-2811-2811-2911-2911-3111-3111-3111-3211-3211-3311-3311-3411-3611-3611-3711-3911-3911-4011-4111-4311-4411-4411-46

v

TM 55-1520-228-BD


Figure Title Page

11-4611-4712-112-212-312-412-513-113-213-313-413-513-613-713-813-913-1013-1114-115-115-215-315-415-515-615-7F-1F-2F-3F-4F-5

F-6F-7F-8F-9F-10

Table No.

2-12-24-14-24-34-44-5

Preparation of Coax . . . . . . . . . . . . . . . . . . . .Installation of Field Expedient Antenna. . . . . . . . . . .0H-58 Fuel System. . . . . . . . . . . . . . . . . . . . . .Emergency Mechanical Clamp Repair . . . . . . . . . . . . .Mixing Instruction for Sealant Cartridges. . . . . . . . . .Rubber Repair Plug Assembly. . . . . . . . . . . . . . . . .Plug Modification for Three Plain Repair . . . . . . . , . .OH-58 Flight Controls Schematic. . . . . . . . . . . . . . .Collective Flight Control. . . . . . . . . . . . . . . . . .Cyclic Flight Control . . . . . . . . . . . . . . . . . . . .Flight Control Actuators. . . . . . . . . . . . . . . . . .Anti-Torque Controls (Sheet 1 of 2). . . . . . . . . . . . .Control Tube Dimensions. . . . . . . . . . . . . . . . . . .Suggested Repair for Control Rods or Tubes . . . . . . . . .Control Rod with Bearing and Clevis Assemblies . . . . . . .Flattened End of Fabricated Flight Control . . . . . . . . .Corner Rounding on Fabricated Flight Control . . . . . . . .Bearing Assembly Connection of Fabricated Flight Control . .Engine De-Ice System. . . . . . . . . . . . . . . . . . . .Bleed Air Heating and Ventilating System A & C . . . . . . .Heating and Ventilating System (Bleed Air) A Model . . . . .Heating and Ventilating System (Bleed Air) C Model . . . . .Combustion Heater. . . . . . . . . . . . . . . . . . . . . .Shroud Heater System Schematic . . . . . . . . . . . . . . .Bleed Air Line Installation. . . . . . . . . . . . . . . . .Bleed Line Patch Repair. . . . . . . . . . . . . . . . . . .Intercom System (Sheet 1 of 2).. . . . . . . . . . . . . .UHF/AM Communications System (Sheet 1 of 2). . . . . . . . .VHF/AM Communications System and Connecting Cables . . . . .VHF/FM Communication System. . . . . . . . . . . . . . . . .Gyromagnetic Compass Set AN/ASN-43 and Connecting Cable(Sheet 1 of 2) . . . . . . . . . . . . . . . . . . . . . . .Direction Finder Set AN/ARN-89 (Sheet 1 of 2). . . . . . . .Radio Receiving Set AN/ARN-123(V)1 . . . . . . . . . . . . .Radar Altimeter System AN/APN-209. . . . . . . . . . . . . .Transponder (IFF) System AN/APX-72, AN/APX-100 . . . . . . .Radar Warning System AN/APR-39 . . . . . . . . . . . . . . .

LIST OF TABLES

Title

General Decision Logic . . . . . . . . . . . . . . . . . . .General Assessment Table . . . . . . . . . . . . . . . . . .Aircraft Structure Damage Assessment Procedures. . . . . . .Damage Limits Forward Fuselage - Condition I . . . . . . . .Damage Limits Aft Fuselage - Condition I . . . . . . . . . .Damage Limits Tail Boom and Landing Gear - Condition I . . .Damage Limits Forward Fuselage - Condition II. . . . . . . .

11-4711-4912-212-512-712-912-913-213-513-613-713-813-1013-1013-1213-1313-1313-1314-215-215-315-415-515-615-1015-11F-2F-4F-6F-8

F-10F-12F-14F-16F-18F-21

Page

2-22-34-24-314-364-394-39

vi

TM 55-1520-228-BD

LIST OF TABLES (Cont)

Table No.

4-64-74-85-16-17-18-19-19-211-111-211-311-411-511-611-712-113-113-213-315-1D-1D-2D-3D-4D-5D-6D-7F-1F-2F-3F-4F-5F-6F-7F-8F-9F-10F-11

Title

Damage Limits Aft Fuselage - Condition II. . . . . . . . . .Damage Limits Tail Boom and Landing Gear - Condition II. . .Metal Substitution Chart. . . . . . . . . . . . . . . . . .Assessment Procedure Logic . . . . . . . . . . . . . . . . .Engine BDAR Assessment Logic . . . . . . . . . . . . . . . .Assessment Procedures. . . . . . . . . . . . . . . . . . . .Drive Train System BDAR Assessment Procedures. . . . . . . .Assessment Logic. . . . . . . . . . . . . . . . . . . . . .Seals Reference and Temperature Guides Chart . . . . . . . .Electrical and Avionics Assessment Logic . . . . . . . . . .Function and Designation Letters . . . . . . . . . . . . . .Unshielded Crimp Splice Application. . . . . . . . . . . . .Wire Repair Segments. . . . . . . . . . . . . . . . . . . .Shielded Cable Repair . . . . . . . . . . . . . . . . . . .Terminal Lugs. . . . . . . . . . . . . . . . . . . . . . . .Fuse Link Strands. . . . . . . . . . . . . . . . . . . . . .Fuel System Assessment Procedures. . . . . . . . . . . . . .Flight Control System Assessment Procedures. . . . . . . . .Nominal Tube Splice Sizes. . . . . . . . . . . . . . . . . .Bolt/Drill Sizes for Control Tube Repairs. . . . . . . . . .Assessment Procedures. . . . . . . . . . . . . . . . . . . .Essential Spare Parts. . . . . . . . . . . . . . . . . . . .Spare and Repair Parts . . . . . . . . . . . . . . . . . . .Weapons. . . . . . . . . . . . . . . . . . . . . . . . . . .Substitute Fuels for JP-4 Fuel . . . . . . . . . . . . . . .Fuels for the OH-58 Helicopter . . . . . . . . . . . . . . .Substitute Commercial Fuels . . . . . . . . . . . . . . . .Alternate and Expedient Fuel Blends. . . . . . . . . . . . .Wire Table, Intercom System. . . . . . . . . . . . . . . . .Wiring Table, UHF/AM Communication System. . . . . . . . . .Wiring Table, VHF/AM Communication System. . . . . . . . . .Wiring Table, VHF/FM Communication System. . . . . . . . . .Wiring Table, Gyromagnetic Compass Set . . . . . . . . . . .Wiring Table, ADF AN/APN-89Radio Receiving Set AN/ARN-123(V)1, OH-58C . . . . . . . . . . Wiring Table, Radar Altimeter AN/APN-209, OH-58C . . . . . .Wiring Table, IFF, APX-72, OH-58A . . . . . . . . . . . . .Wiring Table, IFF, APX-1OO, OH-58C . . . . . . . . . . . . .Wiring Table, AN/APR-39 . . . . . . . . . . . . . . . . . . .

Page

4-444-474-505-36-37-48-69-49-1811-211-311-711-1611-1811-2711-3712-313-313-1113-1115-7D-2D-3D-5D-7D-8D-9D-10F-3F-5F-7F-9F-11F-13F-15F-17F-19F-20F-22

vii

TM 55-1520-228-BD

HOW TO USE THIS MANUAL

This manual is developed to assist the soldier in a battlefield environment to makeassessment and repair of damage to the OH-58 helicopter which cannot, due to assetavailability or environmental factors, be repaired in the normal prescribed manner.Within this technical manual, the word shall is used to indicate a mandatoryrequirement. The word should is used to indicate a nonmandatory but preferredmethod of accomplishment. The word may is used to indicate an acceptable method ofaccomplishment.

1. Organization of the Manual. This manual contains a general information chapter(chapter 1), a general assessment chapter (chapter 2), and specific repair chapters(chapters 4 thru 19). Chapter 3 is not used. It also contains five appendices.References (Appendix A), special or fabricated tools (Appendix B),expendable/durable supplies and materials list (Appendix C), substitute materialsand parts (Appendix D), and BDAR fixes authorized for training (Appendix E).

2. Chapter 2 is used to assess the helicopter in general and references specificchapters for detailed repair procedures of the major functional groups. The majorfunctional groups correspond with the functional groups of the -23 series manualsthat are employed in routine repairs to the helicopter.

3. Chapter 3 is not used in this manual. It would normally contain repairs forequipment which does not fall under one of the standard helicopter functional groups.

4. Each functional group chapter is organized as follows:

a. Section I - Introduction.

(1) Scope. Purpose of the chapter.(2) Assessment procedures. General assessment information for the repairs

covered therein.(3) Repair procedure index.

b. Section II - Repair Item. A subsection is included for each repair itemcovered in that functional group. It contains the following:

(1) General. About the nature and cause of damage and repair.(2) Item and trouble statement with:

(a) Limits given.(b) Personnel and time required to effect repairs.(c) Materials and tools needed.(d) Procedural steps to accomplish the repair.

(3) If more than one method of repair can be used, the various options willbe included next.

NOTE

The first option is the preferred choice, the second optionis the next preferred, etc. Selection of the option shouldbe the most preferred method possible under the circumstancesand with the available materials and manpower.

viii

TM 55-1520-228-BD

HOW TO USE THIS MANUAL (Cont)

5. Finding Repairs in this Manual.

a. When the damage is obvious and known, find the functional group chapter ofwhich the damaged item is a part. Turn to the repair procedure index, section I,subparagraph c of each chapter to locate the item being repaired. Then turn to therepair section and review each option to ascertain the appropriate fix. Read theentire section for the option, then effect the repairs following the proceduresgiven.

b. When the damage is hidden and/or unknown, follow the overall assessment proce-dures provided in chapter 2, and follow the procedures and directions provided.

6. Preparation.

a. Each mechanic/technician shall have read chapters 1 and 2 and become familiarwith the repairs and layout of the manual prior to attempting to accomplish BDARrepairs.

b. All warnings, cautions, and safety precautions shall be followed, inasmuch aspossible, at all times during BDAR procedures so as not to further damage and/orjeopardize either personnel or the equipment during or subsequent to the BDARaction. Ensure all documentation is completed as directed in this manual and bylocal command.

7. Expendable/Durable Supplies and Materials.

a. Each fix or repair option contains a short listing of materials and tools con-sidered basic to the repair. It is important to note that the expendable materialslisted usually cover a wide range for any one item.

Example: MATERIALS/TOOLS REQUIRED:● Drill with Bit●❵ Sheet Metal (items 131-142, Appx C) ● Rivets (items 98-115, Appx C)

In this example, sheet metal covers the range of items 131 thru 142 in Appendix C.This means that, depending on the circumstances and location of the fix, any one ofthese metals could be used. Likewise any one of the rivets, items 98 thru 115, maybe used to attach the patch plate depending on the application.

b. One of the key points concerning successful BDAR repairs is flexibility. Theusers of this manual should strive to use the items on hand, provided a safe repairis made. The stringent requirements of normal maintenance may be lifted.

ix/(x-Blank)

TM 55-1520-228-BD

CHAPTER 1

GENERAL INFORMATION

BDAR FIXES SHALL BE USED ONLY IN COMBAT OR FOR TRAININGAT THE DISCRETION OF THE COMMANDER.

(AUTHORIZED TRAINING FIXES ARE LISTED IN APPENDIX E.)IN EITHER CASE, DAMAGES SHALL BE REPAIRED BY STANDARD

PROCEDURES AS SOON AS PRACTICABLE.

Section I. INTRODUCTION

1-1. PURPOSE. The purpose of BattleDamage Assessment and Repair (BDAR) isto quickly return the disabled heli-copter to the operational commander byexpediently fixing, bypassing, or jury-rigging components to restore the mini-mum essential systems required for thesupport of the specific combat missionfor self-recovery. These repairs willbe temporary and may not restore fullperformance capability. Standard repairwill be completed as soon as practical.

1-2. SCOPE.

a. This technical manual (TM) des-cribes BDAR procedures applicable toOH-58 helicopter series, and theseprocedures are to be used by crew,operators, aviation unit maintenance(AVUM) teams, and aviation intermediatemaintenance (AVIM) support teams.

b. Standard repair techniques for theOH-58 helicopter are included in othertechnical manuals which are referencedin Appendix A of this TM. Details ofthese procedures are not duplicated inwhole in this TM. If the repairs aremore than one page in length, therepairs may only be referenced inappropriate chapter.

c. All possible types of combatdamage and failure modes cannot be pre-dicted, nor are all effective fieldexpedient repairs known. This TM pro-vides guidelines for assessing andrepairing battlefield failures of OH-58helicopters and is not intended to

be a complete catalog of all possibleemergency repairs. The repairs describedhere will serve as guidelines and willstimulate the experienced mechanic/operator to devise repairs as needed torapidly return equipment to operation ina combat situation.

d. The direct replacement of a pieceof equipment by its spare, even underbattlefield conditions, is not a BDARfix and may not be covered is in thisTM. A standard procedure should be per-formed in preference to a BDAR fix whentime and spares are available.

1-3. APPLICATION.

a. The procedures in this manual aredesigned for battlefield environmentsand should be used in situations wherestandard maintenance procedures areimpractical. These procedures are notmeant to replace standard maintenancepractices, but rather to supplement themstrictly in a battlefield environment.Standard maintenance procedures willprovide the most effective means ofreturning damaged equipment to readystatus provided that adequate time,replacement parts, necessary tools, andtrained/qualified repair persons areavailable. BDAR procedures are onlyauthorized for use in an emergencysituation in a battlefield environment,and only at the direction of the com-mander. They are not to be continuedafter the equipment is out of the battleenvironment.

1-1

TM 55-1520-228-BDGENERAL INFORMATION

b. BDAR techniques are not limited tosimple restoration of minimum functionalcombat capability. If full functionalcapability can be restored expedientlywith a limited expenditure of time andassets, it will be accomplished.

c. Some of the special techniques inthis manual, if applied, may result inshortened life or in further damage tomajor components of the helicopter. Thecommander must decide whether the riskof having one less helicopter availablefor combat outweighs the risk ofapplying the potentially destructiveexpedient repair technique. Each tech-nique gives appropriate warnings,cautions, and lists systems limitationscaused by this action.

1-4. DEFINITIONS.

a. Battlefield Damage. Any incidentsuch as combat damage, random failures,operator errors, accidents, and wear-outfailures which occur on the battlefieldand which prevent the helicopter fromaccomplishing its mission.

b. Repair or Fix. Any expedientaction that returns a damaged part orassembly to a full or an acceptablydegraded operating condition, including:

(1) Short cuts in parts removal orinstallation.

(2) Installation of componentsfrom other equipment that can bemodified to fit or interchange withcomponents on the damaged equipment.

(3) Repair using parts that servea noncritical function elsewhere onthe same equipment for the purpose ofrestoring a critical function.

(4) Bypassing of noncritical com-ponents in order to restore basic func-tional capability.

(5) Expeditious cannibalizationprocedures.

(6) Fabrication of parts from kitsor readily available materials.

(7) Jury-rigging.

(8) Use of substitute materials.

c. Damage Assessment. A procedure torapidly determine what is damaged,whether it is repairable, what assetsare required to make the repair, who cando the repair (e.g., crew, maintenanceteam or maintenance support team), andwhere the repair should be made. Theassessment procedure includes thefollowing steps:

(1) Determine if the repair can bedeferred, or if it must be done.

(2) Isolate the damaged areas andcomponents.

(3) Determine which componentsmust be fixed.

(4) Prescribe fixes.

(5) Determine if parts or com-ponents, materials, and tools areavailable.

(6) Estimate the manpower andskill required.

(7) Estimate the total time (clockhours) required to make the repair.

(8) Establish the priority of thefixes.

(9) Decide where the fix shall beperformed.

(10) Decide if recovery or evacua-tion is necessary and to what location.

d. Fully Mission Capable (FMC). Thehelicopter can perform all its combatmissions. To be FMC, the helicopter mustbe complete and fully operable with nofaults listed in the aircraft inspectionand maintenance record as prescribed inDA PAM 738-751.

1-2


e. Combat Capable. Equipment meetsthe minimum functional combat capabilityrequirements. (See paragraph 1-8. )

f. Combat Emergency Capable. Theequipment meets the needs for specifictactical missions; however, all systemsare not functional. Also, additionaldamage due to the nature of an expedientrepair may occur to the equipment if itis used. The commander must decide ifthese limitations are acceptable forthat specific emergency situation.

g.Exchange.

Cannibalization or ControlledThroughout this manual, can-

nibalization and controlled exchange areused interchangeably meaning the removalof an item of materiel from one piece ofequipment for immediate use in another.Generally the rules for cannibaliza-tion/controlled exchange provided inTM 55-1500-328-25, as modified by localauthority, will prevail.

h. Evacuation, A combat service sup-port function which involves the move-ment of recovered helicopters from amain supply route, maintenance collec-tion point, or maintenance activity tohigher categories of maintenance. Themateriel may be returned to the user, tothe supply system for reissue, or toproperty disposal activities.

i. Recovery. The retrieval of immo-bile, inoperative, or abandoned OH-58helicopter from the battlefield orimmediate vicinity, and its movementto a maintenance collection point, themain supply route, or a maintenanceactivity for disposition, repair, orevacuation.

j. Self-Recovery. The ability of abattle damaged helicopter to retrieveitself (fly out) from a battlefieldenvironment. It usually will involveflying with degraded flight status andwith restrictions and limitations placedon performance characteristics such aslimitations placed on weight, airspeed,engine torque, and other characteristics.In BDAR repairs, the limitations recom-mended should be followed. Emergencyflight procedure in TM 55-1520-228-10should further be consulted.

k. Maintenance Collection Point. Apoint operated by AVIM unit for thecollection of equipment for repair.

1. Maintenance Support Team (MST). Ateam of AVIM mechanics and technicalspecialists who are trained in assessingbattlefield damage and field repairprocedures.

m. Maintenance Team (MT). Helicoptercrew chief or AVUM mechanics/technicianswho are trained in assessing battlefielddamage and field repair procedures.

1-5. QUALITY DEFICIENCY REPORT/EQUIP-MENT IMPROVEMENT RECOMMENDATION(QDR/EIR). If your helicopter and itsequipment need improvement, let usknow: Send us an EIR. YOU, the user,are the only one who can tell us whatyou don’t like about your equipment.Let us know why you don’t like thedesign. Put it on an SF 368 (QualityDeficiency Report). Mail it toCommander, U.S. Army Aviation SystemsCommand, ATTN: AMSAV-QF, 4300Goodfellow Boulevard, St. Louis, MO63120-1798. We’ll send you a reply.

Section II. STANDARDS AND PRACTICES

1-6. BDAR CHARACTERISTICS. BDAR capa- standard peacetime maintenance practices.

bility requires simplicity, speed, and In a combat emergency situation, greatereffectiveness. Some BDAR procedures risks are sometimes necessary andinclude repair techniques that violate acceptable.

1-3


1-7. WAIVER OF PRECAUTIONS. Undercombat conditions, BDAR may be performedon helicopters which are in flight orwhich are under power while on theground. While some of these BDAR actionsmay require waiving of safety precautions,the cautions to protect personnel lifeshould not be overlooked. Other similarprecautions may be waived at the discre-tion of the commander. BDAR fixes maybe required in a chemically toxic environ-ment or under other adverse battlefieldconditions with severe limitations inpersonnel, facilities, equipment, andmaterials. Performance of repair tasksmay be necessary while wearing protectivegear. Decontamination procedures aredescribed in FM 3-5.

OPERATING CHARACTERISTICS. Thismanual covers expedient repairs for theOH-58 helicopter and its components. Itis entirely possible that in a combatsituation, the helicopter having under-gone one or more repairs may sufferdegradation of its normal operatingcharacteristics (e.g., reduced speed,reduced load capability, reduced range,etc.), and still be able to carry outall or parts of an assigned mission.The minimum functional combat capability(MFCC) criteria for the OH-58 is asfollows:

a. Flight Capability for MissionCompletion. Helicopter’s flight charac-teristics degraded to a minimum ofcombat capable (CC).

(1) Sufficient power delivered tomain and tail rotor to accommodate lift

(4) Communications. Must haveintercom communications within aircraftand at least two tactical receiver-transmitter (R-T) units operating atfull capability.

NOTE

Criteria may be waived forrecovery or if the tacticalsituation demands otherwise.

b. Flight Capability forSelf-Recovery Capability (SRC).

(1) Must have power delivered tomain and tail rotor at acceptablelimits.

(2) Maximum engine torque:

80% at 0 kts64% at 16 kts53% at 32 kts50% at 50 kts

(3) Lift capability for crewmembers. Unload unnecessary weight.

(4) Flight controls at minimumfunction level acceptable for flight.

(5) Instruments/avionics asrequired to meet mission needs.

(6) Maximum airspeed of 50 kts.

(7) Maximum flight duration of2 hours. Consideration will be givento minimize flight duration.

capability for helicopter crew and cargo. (8) Be prepared for emergencyprocedures. See TM 55-1520-228-10,

(2) No fuel leaks which will cur- Chapter 9.tail the intended length of flight.

(3) No degradation of any com-ponent/system which will end in failureand curtailment of intended mission.

1-4

1-8


WARNING

Careful consideration shall be givento the operation of the IdentifyFriend or FOE (IFF), Mode 4,avionics system. Failure of theIFF or failure to properly communi-cate with area air defense commandprior to liftoff could result in anattack from friendly forces due tomistaken identity.

1-9. TRAINING.

a. BDAR by its nature involves fixes,bypasses, and/or jury-rigging, which is

outside authorized standard repairs, andmay degrade the inherent safety of thehelicopter. Therefore, BDAR actions arenot intended to supplement, replace stan-dard maintenance practices during peace-time, nor should they be employed indis-criminately to facilitate training.

b. Repairs described in this manual,which can be appropriately accomplishedin order to provide training, are listedin Appendix E and are highlighted in eachrepair chapters repair procedure index.The trainable repair in the index will beblocked in.

Section III. TASKS AND RESPONSIBILITIES

1-10. TAGGING/IDENTIFYING BDAR REPAIRS.

a. All damage will be identified onaircraft inspection and maintenancerecord, DA Form 2408-13 and DA Form2408-18, as per DA PAM 738-751. SeeFigures 1-1, 1-2.

b. Recording of BDAR repairs and theuse of status symbols, as defined in DAPAM 738-751, will be completed as soonas practical to indicate any limita-tions and restrictions or required stan-dard repairs.

c. In addition to recording alldamage, the area damaged will be markedon aircraft or component part usingdamage assessment markings as shown inFigure 1-3.

d. Status Symbols. Status symbolsused in aircraft logbooks to recorddefects are defined below.

(1) Red “X.” A red “X” shows thata defect exists and the aircraft isunsafe for flight.

(2) Circled red “X.” A red “X”inside a red circle indicates a limitingdefect. The aircraft may be flown underspecific limits as directed by higherauthority, or as directed locally untilcorrective action is taken.

(3) Red horizontal dash (-).

(a) This symbol indicates aninspection, special inspection, com-ponent replacement, maintenance opera-tional check, or test flight is needed.The symbol is also used to indicate thata normal modification work order (MWO)is overdue.

(b) This symbol also shows thatthe condition of the equipment isunknown. A potentially dangerous con-dition may exist. The condition will becorrected as soon as possible.

(4) Red diagonal (/). This symbolindicates a defect exists that is notserious enough to ground the aircraft.

1-5


e. Maintenance of Forms. Instruc-tions for the maintenance of forms,records, and reports are listed in DAPAM 738-751 and TB 55-1500-307-24. Whenbattle damage assessment and repair(BDAR) becomes necessary, the proceduresin DA PAM 738-751 will apply. Refer toFigures 1-1 and 1-2 for examples.

(1) In block 17 of DA Form2408-13, list the fault.

(2) In block 16 of DA Form2408-13, enter the status symbol.

(3) In block 18 of DA Form 2408-13,enter the corrective action taken.

(4) The individual completing therepair will sign the form in block 19opposite the first line of the actiontaken, and will place his last name ini-tial over the status symbol in block 16.

f. Temporary Repair. If the repairis temporary, take the following addi-tional action:

(1) In block 18 of DA Form 2408-13,enter the corrective action and a state-ment that the repair is temporary. Thenmake an entry in DA Form 2408-14, blockb. The entry will be a duplicate of theentry in block 17 of DA Form 2408-13 toinclude a statement that a temporaryrepair has been made.

(2) If the temporary repair limitsthe capability of the aircraft, thefollowing entry will be made on DA Form2408-13:

(a) Place a circled red “X” inblock 16.

(3) If the temporary repairrequires an inspection at intervals,list the required inspection on DA Form2408-18.

(a) Enter item to be inspectedin block 5.

(b) List the applicable TM inblock 6.

(c) State the frequency of theinspection in block 7.

1-11. REPORTS. All written reportsrequired for BDAR fixes are found in DAPAM 738-751. If the helicopter can nolonger fly, the aircraft commandershould immediately initiate an out-of-action report to his superior. If com-munications capability is damaged, theaircraft commander should approach thenearest friendly radio and make hisreport if possible. The report shouldinclude these essentials:

a. Aircraft damage (out-of-action orfunction partially impaired).

b. Location of aircraft.

c. Defense status.

d. Mobility.

e. Personnel report.

f. Current and anticipated hostileaction.

Anticipated BDAR fixes and repairtime.

(b) State the limitation inblock 17.

1-6 Change 1

g.

NOTEFaults with status symbol of red "x", orcircle red "x" will not be entered on DA form 2408-14.

1. DATE 2 MODEL 3. SERIAL NO. 4 NAME OF CREW CHIEF/MECHANIC 5 STATlON 6 PAGE NO. 6a NO. OF PAGES

I7 STATUS TODAY 8 AIRCRAFT TIME 9 NEXT INSPECTION DUE HOT STARTS

AIRCRAFT ELEC- ARMA- OTHER TIME TOINTMED LANDINGS OTHER

TRONIC MENTN0.1

DATE E N G I N E ENGINE b c

1 4 P.E. NO. PREVIOUSTIME TO-

2DAY

5 TODAY

TOTAL3

OTHER

6 TIME TOTAL

11FUEL (Gals or Lbs)

12OIL ( Quarts) 13 14 15

SERVICEDANTl-

SERV-0XYGEN ICING

TOTAL ADDED TOTALGRADE ADDED

ADDED TOTAL FLUIDIN GRADE N0. 1 IN

TANKSN0. 2

ENGAPU

TANKS ENG TANKS(Gals) BY STATION

1

2

3

4

5

6

7

TOTAL

16 STATUS17 FAULTS AND/OR REMARKS 18. ACTION TAKEN 19 S I G N A T U R E

ICE

NO.NO. 2

NO. IN (PSI)

I

I I 1

DA FORM 2408-13, 1 DEC 66 REPLACES EDITION OF 1 JAN 64, WHICH WILL BE USED AIRCRAFT INSPECTION AND MAINTENANCE RECORD

For use of this form see DA PAM 738-751, the proponent army is DCSLOG

TM 55-1520-228-BD

GENERAL INFORMATION

F i g u r e 1 - 1 . D A F o r m 2 4 0 8 - 1 3

1-7

1. NOMEN CLATURE 2. MODEL 3. SERlAL NUMBER 4. PAGE NO.

NO. OF PAGES

5. ITEM TO BE INSPECTED 6. REEFERENCE 7. FREQUENCY 8. NEXT DUE

●

DA FORM 2404.18. 1 JAN 64 EQUIPMENT INSPECTION LISTFor use of this form, see TM 38-750;the proponent agency is DCSLOG.


Figure 1-2. DA Form 2408-18

1-8


MEANINGS

TO INDICATE DAMAGE HAS BEEN ASSESSED AND EVALUATED:

Draw a circle around the damage.

TO INDICATE NO BDAR REPAIR REQUIRED:

Write “OK” inside the circle.

MARKINGS

TO INDICATE STRUCTURAL REPAIRS ARE REQUIRED:

Draw a second line about 1/4 to 1/2way around the initial circle thendraw slashes or crosshatch betweenthe two circular lines.

STRINGER REPAIR: Place an X to theleft and right of the circle.

FRAME REPAIR: Place an X above andbelow the circle.

TO INDICATE DAMAGE TO SYSTEMS REQUIRING REPAIRS:

Draw a series of “curly cue” lines about1/4 to 1/2 way around the initial circle.

TO INDICATE REPAIR INSTRUCTIONS:

For internal damage - draw a dashedcircle around the repair instructions.

For external damage - write repairinstructions but do NOT enclosewith a circle.

Figure 1-3. Damage Assessment Markings (Sheet 1 of 3)

1 - 9


WRITTEN INSTRUCTIONS MEANING

See me - print name & See assessor or whoever has signed written instructionsrank. (Signature) for additional information.

Names of parts to Where compound damage occurs, the names or abbreviationsbe repaired, (item, of specific items can be written adjacent to the damageskin, stringer. to clarify repair instructions.

Full A full strength repair is required.

Partial Partial strength repair required in accordance withspecific aircraft BDAR manual.

OK No repairs required - damage is within acceptable limitsfor battle conditions.

? Continual assessment or reinspection is required aftereach sortie.

Instruction markings for system are in two parts:

(1) Repair instruction markings and meanings are shown on this sheet and areused to indicate repair actions required.

(2) System Identification - When known, identify the system using markingsshown on sheet 3 of this figure.

MARKINGS MEANING

Fix Repair the damaged system in accordance with approvedstandard BDAR techniques for type of system, item,high pressure, low pressure, etc.

Cap

Repl

OK

Tag

Terminate or block the system to prevent leakage.

Replace damaged part - repairs not acceptable.

No repairs required.

Repair instructions are written on tags tied to indivi-dual damaged lines/components.


1-10


System identification markings are primarily abbreviations of the system.

MARKINGS SYSTEM/MEANING

Sys Damage to unknown system.

Fuel Fuel

Hyd Hydraulic

HP High Pressure

LP Low Pressure

Elect Electrical

AV Avionics

Flt Cont Flight Control

Main Rotor Main Rotor Group

Tail Rotor Tail Rotor Group

Air Pneumatic

Air Cond Air Conditioning

BL Air Bleed Air System

BLC Boundary Layer Control

N2 Nitrogen

O2 Oxygen

Eng Contr Engine Control

Pow Tr Power Train

EJ Ejection

NOTE

More than one identification marking may be used to describethe system (e.g., HP, Hyd).


1-11/(1-12 Blank)

TM 55-1520-228-BD

CHAPTER 2

ASSESSING BATTLEFIELD DAMAGE




Section I.

2-1. SCOPE.

a. This chapter provides guidelinesto use in assessing battlefield damageto the OH-58 helicopter. It directs youto an expedient BDAR fix or to the stan-dard system fix of TM 55-1520-228-23-1,2if an expedient BDAR repair does notexist. General decision logic chart,Table 2-1, assists in BDAR discussions.

b. Each chapter will have a specificfault assessment chart for each func-tional group and this flow chart willdirect you to specific BDAR fixes forand within the functional group.

c. Use the following guidelines tofind and fix sustained damage orsuspected damage to your helicopter.Keep in mind that damage can besustained while on the ground or inflight. The helicopter location canhave a considerable effect on theassessment. The following appraisalshall be accomplished.

(1) If possible and time permits,inspect and check the helicopter usingoperator’s check list (CL), operator’smanual (-10), and other records andforms kept in aircraft log book. Atthe same time be looking for obviousdamage to aircraft.

INTRODUCTION

(2) If applicable and possible,use standard troubleshooting recommen-dations in TMs.

(3) If you find a problem, deter-mine its effect on helicopter’s mobi-lity and capability.

(4) If you cannot fix the problemwith standard fixes, apply this TM and use general and specific assessmenttables, charts, and BDAR action.

(5) If the damage does not affectaircraft’s flying status, the aircraftor flight commander will decide whetherto fix or defer fix, and continue orstart mission.

(6) If damage does affect flightstatus, do one of the following:

(a) Replace damaged part with aserviceable part.

(b) Replace damaged part withsuitable substitute if it exists.

(c) Apply a BDAR fix.

(7) After repairing the damage,replace all lost fluids/lubricants. Ifone specified by aircraft TM is notavailable, refer to Appendix D foralternative materials/parts.

2-1

TM 55-1520-228-BDASSESSING BATTLEFIELD DAMAGE

Table 2 -1 . Genera l Decis ion Logic

SEE TM 55-1520-328-25

2-2


d. General aircraft assessment charts,Table 2-1, guide you through the air-craft’s capability so that all thenecessary capabilities are evaluated.If a fault is found, Table 2-1 directsyou to the chapter for the functionalgroup which contains the fault. TheBDAR assessment procedure will refer you

to a guide fix in this manual, a stan-dard TM 55-1520-228-23 repair if it isfeasible, or a higher AVIM level ofrepair if extent of damage, time con-straint, tooling requirements, repairpart or material, and any other necessaryrequirements are only available at ahigher level of maintenance.

Section II. GENERAL FAULT ASSESSMENT TABLE

2-2. GENERAL FAULT ASSESSMENT TABLE. Refer to Table 2-2 for assessment logic flowchart.

Table 2-2. General Assessment

2-3


Table 2-2. General Assessment (Cont)

2-4

TM 55-1520-228-BD

ASSESSING BATTLEFIELD DAMAGE


2-5



2-6



2-7

I

2 - 8

TM 55-1520-228-BDASSESSING BATTLEFIED DAMAGE




I

2-9/(2-10 Blank)

TM 55-1520-228-BD

CHAPTER 3

GENERAL REPAIRS


(AUTHORIZED TRAINING FIXES ARE LISTED IN APPENDIX E.)IN EITHER CASE, DANAGES SHALL BE REPAIRED BY STANDARD


No general repairs have been identified Chapters 4 thru 19 for functional groupfor this model helicopter. Proceed to assessment and repair procedures.

3-1/(3-2 Blank)

TM 55-1520-228-BD

CHAPTER 4

AIRFRAME





4-1. SCOPE. This chapter containsinformation on battle damage assess-ment and expedient repair proceduresfor the OH-58 helicopter airframe.The procedures are to be used onlyduring combat operations or duringperiods of extreme emergency.

a. Section I contains informationpertaining to the various structuralareas which are suspected of beingdamaged, and whether the damage is to aprimary or secondary element. Logicflow chart tables and damage limittables are also part of this section.

b. Section II consists of expedientstructural repairs and procedures onhow to perform these repairs and fieldfixes.

4-2. ASSESSMENT PROCEDURES. Refer toTable 4-1.

4-3. GENERAL. Aircraft structure isclassified as primary and secondarystructure.

a. The primary structure is the basicstructure which holds the aircrafttogether. Any serious damage to anyelement of the primary structure willrestrict the combat capability of theaircraft. The primary structure foreach major airframe subassembly isshown in Figure 4-11, Sheets 1 thru 5.

b. Secondary structures are mountedon the primary structure. No amountof structural damage to secondary struc-tures will restrict combat capabilityfrom a structural point of view;

however, secondary structure may berequired for aerodynamic reasons or toaccomplish or support mission functions.

4-4. STRUCTURAL DAMAGE ASSESSMENT ANDREPAIR. The battlefield structuraldamage assessment and repair consists ofthree steps: an initial assessment,paragraph 4-5; a detail assessment,paragraph 4-6; and a repair plan,paragraph 4-10. The initial assessmentis a quick visual assessment to decidewhether or not a detail assessmentshould be made. A detail assessmentinvolves the identification of alldamage to primary structural elements,possibly some clean-up and measurementof the damage and of the damaged ele-ments. The procedure is described forvarious aircraft sections in thischapter. This process requires damagemeasurement and determination of thecorresponding damage limits. The repairplan is based on an analysis of thedetail assessment. An overall view ofall the aircraft zones is shown inFigure 4-1.

4-5. INITIAL ASSESSMENT. To perform aninitial assessment, the assessor must beacquainted with structural damage modesand the primary structure as shown inthe figures of this chapter. He shallbe capable of differentiating betweenprimary and secondary structure, and hemust understand the function of primarystructural elements. The initial assess-ment consists of a visual inspection ofprimary structure. The assessor deter-mines if any primary caps, webs, orpanels are damaged or fractured anddecides whether:

4-1

TM 55-1520-228-BDAIRFRAME

4-2

Table 4-1. Aircraft Structure Damage Assessment Prodecures


Figure 4-1. Aircraft Sections

4-3


a. the damage appears to bedeferrable;

b. a detail assessment can be madeand the damage can be repaired by BDARtechniques within the time available toreturn the aircraft to service in theongoing battle;

an adequate assessment can be madeand the damage can be repaired by BDARtechniques to enable the aircraft toself-recover;

d. a detail assessment cannot bemade and/or the damage cannot be re-paired by BDAR techniques within theavailable time. The aircraft shall bescheduled for standard repair.

e. The aircraft is damaged beyondrepair, and he shall arrange for itsdisposition (i.e., recovery, can-nibalization, or destruction).

4-6. DETAIL ASSESSMENT.

a. Access to Damaged Structure.Locate all damage to airframe primarystructure. Remove access panels,covers, and fairings in the damagedarea. Remove aircraft components asrequired to inspect the structure. Usethe location of entrance and exit woundsand the estimates of projectile paths todetermine the areas where damage may bepresent and access to interior inspec-tion will be needed. If an area ofstructure suspected of being damagedcannot be reached by other means, cutsmall inspection holes in the exteriorskin. Then inspect internal memberswith an inspection light and mirror.

b. Inspecting for Cracks.

(1) Inspect for cracks caused byimpact or penetration in regions awayfrom the site of primary damage.

(2) Inspect for small and largecracks caused by projectile damage.Small cracks will enlarge under con-tinued loading, particularly whenlocated at the edge of a hole.

(3) Locate cracks in primarystructure using magnifying glass or dyepenetrant. Check for cracks aroundfasteners in areas showing signs ofoverstress.

(4) Inspect for cracks in allareas of an explosion caused by a highexplosive incendiary (HEI) strike.

c. Inspecting for Structural Changes.

(1) Inspect damaged area andsurrounding undamaged area for evidenceof buckling, crippling, and misalign-ment. Kinks, wrinkles, and sheared,pulled-through or missing fasteners onskin panels are indications of struc-tural changes by an HEI hit.

(2) Inspect structural changes inthe form of buckling, crippling, andmisalignment caused by overpressure.These structural changes are noticeablein areas where one structural member mayhave to support the load of anotherbroken member. Check damaged area to seeif there is interference with mechanicalmoving components.

(3) Use a straight edge to examinethe component for twisting or bowing.

d. Inspecting for EmbeddedProjectiles and Fragments.

(1) Inspect for embedded projec-tiles which can create the same affectas a hole or crack on a tension member.

(2) Inspect for embedded projec-tiles and fragments in areas which havesuffered HEI damage. The inspectionwill reveal that a solid projectile isembedded or has broken apart, strikinginternal components.

4-4

c .


(3) Inspect all structures usingbright light and magnifying glass.Determine the path entry of the projec-tile to aid in finding structures thatmay have embedded fragments. Markembedded objects and record them on DAForm 2404, Figure 4-2.

e. Inspecting for Fire Damage.Inspect for fire damage by checking fordiscoloration of the structure. Anydiscoloration will indicate that themember has been exposed to high tem-perature. Conduct a hardness test todetermine if the temperature of thematerial has changed. If test indicatesheat damage, record the information onDA Form 2404 and clearly mark themember.

f. Detecting Structural Damage inAdjoining Areas.

(1) Secondary damage can be theresult of severe overstress, explosiveblast, or maneuvering loads imposed ondamaged structures. Inspect theairframe near the projectile damage forevidence of secondary damage.

(2) Inspect the skin for creases,wrinkles, and dents. Inspect fastenersfor chipped or flaked paint, looseness,and serviceability. If these conditionsare evident, remove access panels anddoors to inspect members for cracks andstructural changes.

Inspecting for broken and missingfasteners. Inspect fasteners forsecurity, shear, pull-through, tear-out,and elongated fastener holes. Wherepossible, inspect fasteners from bothsides.

h. Inspecting for Delaminations.Inspect honeycomb structures for voidsand delamination using the coin tappingmethod.

i. Marking and Recording Damage.

(1) Record all detected damage.Refer to Table 4-1 for repair/referral ofrepair on structural member.

(a) Record name of aircraftsection containing the damaged element,Figure 4-1.

(b) Record the name of thedamage element such as frame, stringer,or skin panel.

(c) Describe the location ofthe damaged element such as station,waterline, butt line, or panel location.

(d) Describe the damage to theelement using terms such as hole, crack,or buckle.

(e) Continue damage recordingfor:

1 Other damages to the sameelement.

2 Other damaged elements inthe same subassembly.

3 Other damaged sub-assemblies in the section of theairframe.

4 Other damage sections ofthe airframe as required.

(f) After the damage inspectionis completed, file the damage report inthe aircraft log book and make entriesas required.

(2) Damage diagrams. Show thelocation and extent of damage as shownin the diagrams in Figure 1-3. Thedamage can be drawn by hand. Accuratelylocating damage on a diagram willgreatly help the damage assessmentprocedure.

4-5


Figure 4-2. DA Form 2404

4-6

(3) Marking damage. Mark thedamaged structure using grease pencil orpaint. Use the labeling scheme shown inFigure 1-3.

CAUTION

Use of lead pencil in some areaswill cause corrosion.

(a) Use a bright color tooutline each area of damage as it islocated and recorded on the DA Form2404. Attempt to make the outlinevisible from all angles.

(b) Draw arrows on inside skinpanels, webs, and bulkheads to pointtoward areas of damage that are hidden.

4-7. DAMAGE MEASUREMENT. If theassessment indicates that the damageshould be repaired by BDAR or standardprocedures, no damage measurement isnecessary. Damage measurement isrequired to determine if structuralrepair (other than cleanup) can bedeferred, or if self-recovery of thedamaged aircraft is feasible. Damagemeasurement may also be required if aBDAR repair does not restore originalstrength. Begin damage measurementwith the largest damage.

a. Damage Measurement of TypicalSections.

(1) The parameters involved inmeasuring damage to typical sectionsare shown in Figure 4-3. The per-tinent values are:

CD = Depth of damage.CL = Length (width) of damage.A = CL x CD = area of damage.D = Distance between damages.

In Figure 4-4, the length of the flat-tened cross section of the angle is:

a + b

CD is the depth of the damage into theflattened cross section. The length ofthe remaining effective cross sectionis still capable of supporting a load.All dimensions are in inches.

CS = (a+b)-CD

(2) When measuring damage, use thefollowing procedure:

(a) Clean all damaged areasthoroughly. Use brushes and swabs toremove dirt and film from small creviceswhere damage may be present.

(b) Smooth all jagged and roughedges and be sure to cut out all radiatedcracks. Use largest corner radii possiblein the cut-outs; avoid sharp corners.

(c) Measure damage aftersmoothing, or if measuring beforesmoothing, make allowance for thematerial which must be removed duringsmoothing. See paragraph (d) below.

(d) Use a steel rule graduatedin tenths of an inch and measure eachdamage dimension to the next higher tenth.

(e) Include the size of thehole when measuring damage that extendsinto a fastener hole or lightening hole.

(f) Record on DA Form 2404.

b. Webs, Panels, and Skins.

(1) Refer to Figures 4-5 and 4-6for the measurements of “WL” and “D.”"WL" is the largest dimension across thedamage, regardless of direction, andmust include all radiated cracks. "D"is the distance between damages. Takeand record measurements as described inparagraph 4-7.a(2).

4-7

TM 55-1520-228-BD AIRFRAME


Figure 4-3. Evaluating Damage to Angles, Channels, and Z-Angles

4-8


Figure 4-4. Damaged Cross Section

4-9


Figure 4-5. Measuring Skin Panel Damage

4-10

IMPORTANT: MEASURED LATERAL DAMAGE MUST

INCLUDE ALL RADIATED CRACKS.


Figure 4-6. Measuring Damage in Webs and Panels

4-11

TM 55-l52O-228-BDAIRFRAME

(2) Honeycomb Sandwich Structures.Refer to Figure 4-7 for the measurementof "WL" and "D." If a projectile hitsa sandwich panel at an angle, thedamages in the two skins may be off-setand of different sizes. Measure thedamage on the side with the largestdamage (usually the exit side), and makesure that the measurement includes thedamaged area on the other side. "WL" isthe largest dimension across the damage(both sides), regardless of direction,and must include all radiated cracks.“D” is the distance between damages.Take and record the measurements asdescribed in paragraph 4-7.a(2).

c. Fittings, Attachments, andSplices.

(1) See paragraph 4-12.

(2) Record all damage on DA Form2404, Figure 4-2.

d. Damage measurements apply aftercleanup and smoothing or after BDAR hasbeen accomplished. However, as a prac-tical matter, measurements must be takenbefore smoothing to make a decision ondeferrability. Hence, when estimatingdamage limits before cleanup and smooth-ing, make allowance for the materialthat will be removed in smoothing. Thisapplies particularly to cracks. Thelength of the crack must be included inin the depth (CD) and length (CL)measurements.

4-8. ALLOWABLE DAMAGE LIMITS DEFINITION.

a. The allowable damage limitscorresponding to the damage measurementsof paragraph 4-7 are designated for agiven condition as follows:

CD' = Allowable depth of damage.CL' = Allowable length (width) of

damage.A' = Allowable area of damage.D' = Minimum allowable distance

between damages.WL' = Allowable largest dimension

across web/panel damage.N = Minimum damage factor.

b. Allowable damage limits for pri-mary structural elements are associatedwith the conditions of paragraph 4-9. Adamage limit for a given condition is ameasure of the amount of damage that astructural member can sustain and stillsupport the loads associated with thegiven condition.

c. For a given condition, all damagesmust be equal to or less than thecorresponding allowable damage limits,and the distance between damages must beequal to or greater than thecorresponding minimal allowable limit;that is:

CD < CD'CL < CL'WL < WL'D > D '

The aircraft may be released for flightin that condition. Repair may bedeferred, although some cleanup andsmoothing of the damage will berequired, as will inspection for damagegrowth after every flight. Special con-sideration should be given to damageexposed to the airstream, particularlyto the effects of ram air, rain, andpetaling. Petals may vibrate in thepassing airflow, rapidly creating cracksin the supporting base metal. Largepieces of metal may peel off and damageother parts of the aircraft. Thedistance D between damage sites for moststructures has a minimum requiredspacing. The spacing requirement isexpressed as a multiple factor (N) of themeasured area of damage.

4-12


Figure 4-7. Measuring Damage in Honeycomb Sandwich Panels

4-13


(1) The factor applies to thedamage actually measured not to themaximum damage limit for the structure.

(2) The factor applies to thelargest dimension of the largest damagebetween which separation is beingmeasured.

(3) The factor applies only if thedimensions of both damages, when addedtogether, exceed the single damagelimit.

4-9. CONDITION. Condition is an indi-cator of the residual capacity of adamaged structural element to performits function. Battlefield damagedstructures or BDAR repaired structuresare classified in three conditions:

a. Condition 1. Aircraft fullyflight capable. No flight restrictions.However, on a battlefield under thepressures of time and tactical situa-tions, the assessment of structuraldamage may not have found all the dam-ages. Therefore, aircraft with struc-tural damage, whether repaired or repairdeferred, should be inspected afterevery flight. The inspector shouldlook for crack growth, evidence ofoverstress, growth of allowable defor-mations, and for the development of newcracks at other locations.

b. Condition 2. Self-recoverycapable. Self-recovery may be requiredto move a damaged aircraft to a repairsite or from one site to another whentowing is not feasible. Self-recoveryis preferable to disassembly and boxingan aircraft for transportation. As timepermits, proceed as follows:

(1) Mark all visible cracks andthe extent of other structural damagewith chalk, grease pencil, paint, tape,or other available means so that anygrowth in the damage can be quicklyrecognized.

(2) Perform any feasibleon-site BDAR fixes as required forself-recovery.

(3) Unload all ammunition,weapons, stores, and unnecessary equipment.

(4) The following restrictionsare imposed on a recovery flight:

(a)

(b)

(c)2 hours.

(d)pedal movementsaircraft.

(e)

Maximum airspeed: 50 kts

Maximum engine torque:

80% at O kts64% at 16 kts53% at 32 kts50% at 50 kts

Maximum flight time:

Use gradual and smoothto minimize loads on

Land at level attitude;soft touchdown from hover.

c. Condition 3. Structural damageexceeding condition 2 limits generallydoes not allow self-recovery. Thedamage may or may not be repairable byBDAR techniques. The airframe may be soextensively damaged that no useful orneeded functions can be restored withinavailable time and resources. Theseaircraft will be:

(1) Recovered or evacuated to afacility with the resources to repairthe airframe.

(2) Used as a source of cannibal-ized components.

(3) Destroyed. This is a lastresort. These conditions apply to theprimary structure and should not be con-fused with the mission capabilityclassifications. Mission capability isdependent on equipment condition.

4-14


d. The type, extent, and variation ofdamage under condition 3 does not per-mit categorization of the many com-binations of damage. Self-recovery, ifconsidered, will depend on the extentand type of damage, type of terrain,distance, and urgency of the situation.

If judgment and experience indicateself-recovery is feasible, it should beaccomplished at minimum weight, altitudeand airspeed with an occasional stop tocheck on the condition of the aircraft.

4-10. REPAIR PLAN.

a. The damage measurements and ini-tial repair data obtained from thedetail assessment must be organized andformulated into a repair plan.

b. Repair requirements includingcleanup/smoothing, condition, andrepair times should be recorded on DAForm 2404.

c. If the worst case is better thancondition 1, repair may be deferredexcept for cleanup and smoothing of allrough edges. The ends of all cracksmust be stop drilled.

d. If the worst case is betweencondition 1 and 2, a decision must bemade to degrade the aircraft tocondition 2 or to repair the aircraftand restore it to condition 1.

(1) If the aircraft is degraded tocondition 2 and is to perform a recoveryflight, severe damage should be cleaned-up, rough edges smoothed, and cracksstop drilled.

(2) If it is decided to restorethe aircraft to condition 1,

(a) determine the requiredrepairs for all damaged structuralelements that are below condition 1.

(b) Repairs on damaged struc-tural elements that are better thancondition 1 may be deferred except forcleanup and smoothing.

e. If the worst case is betweencondition 2 and 3, a decision must bemade to degrade the aircraft tocondition 3 or to repair the aircraftand restore it either to condition 1or 2. An aircraft in this condition isprobably so badly damaged that it maynot be restored to condition 1 withinthe available time. However, everyeffort should be made to restore it tocondition 2 or better if at all possiblefor recovery.

(1) If the aircraft is degraded tocondition 3, no repair is required.


(a) determine the requiredrepairs for all damaged structuredelements that are below condition 2.

(b) Repairs on damaged struc-tural elements that are better thancondition 2 may be deferred except forsome cleanup and smoothing of the badlydamaged areas.


(a) determine the requiredrepairs for all structural elements thatare below condition 1.

(b) Repairs on damaged struc-tural elements that are better thancondition 1 may be deferred except forcleanup and smoothing.

f. Once all decisions are made and arepair plan formulated, complete repairs.Attach DA Form 2404 to DA Form 2408-13and indicate deferred repairs on DAForm 2408-13.

4-15


4-11. GENERAL.

a. The aircraft consists of threemain sections. The forward cabin sec-tion extends from the cockpit nose atFS1 to the bulkhead aft of the passengercompartment at FS130. The aft cabinsection extends from FS130 to FS205where the tail boom is attached. Thethird section is the tail boom. Referto Figure 4-8.

b. The forward section utilizes alu-minum honeycomb and sheet metal struc-tures for the major load carryingelements. The forward section providesfor pilot and passenger seating, fuelcell enclosure, and pylon support.Honeycomb sandwich is used extensivelyin this section, including the upper andlower shells, seat panels, and somebulkhead panels. The remainder is ofconventional thin sheet metal construc-tion. Primary loads forward of FS73 aretaken by the lower console, pedestal,and lower shell. The cabin enclosuresection between FS73 and FS130 is a X -Z planar frame consisting of the centerpost at FS73, roof beam, lower shell,and bulkhead and enclosure at FS114 andFS130. Refer to Figure 4-9.

c. The aft section utilizes an alumi-num and honeycomb semimonocoque construc-tion and provides a deck for engineinstallation and a compartment under theengine deck for electrical equipment.This section utilizes conventional thinsheet metal structure composed oflongerons and bulkhead frames as beamelements and decks and skins as shearpanels. Some of the fairing and decksare honeycomb panels.

d. The tail boom is a circular sec-tion with a horizontal stabilizer, ver-tical fin, and anti-torque rotorattached. The tail boom is a full mono-coque structure utilizing a tapered cir-cular section of aluminum alloy skin.Redistribution in the forward end, whichis required to transfer loads from the

monocoque structure to the four attach-ment fittings on the fuselage, isaccomplished by the use of intercoastalsand two aluminum redistributionbulkheads. The horizontal stabilizeris a standard spar-rib-skin rivetedconstruction. The vertical fin is ofstandard sandwich construction usingaluminum honeycomb core and thinaluminum skins. The upper half of theupper fin is composed of fiberglass skinsand honeycomb core.

e. The damage assessment proceduredescribed in paragraph 4-5 consists ofdamage measurement, determination of thecorresponding allowable damage limit andassociated condition, and formulatingrepair instructions. This data isrecorded on DA Form 2404.

4-12. DAMAGE MEASUREMENT.

a. Refer to Figures 4-8 thru 4-15 forlocation and identification of majorfuselage and tail boom structural areas.

b. Refer to paragraph 4-8 and foreach damaged element, measure the depth“CD” and the length (width) “CL” or “WL”of each damage. Count the number ofdamages and measure the “D” betweendamages. Start with the worst damage.Record these values for each damagedelement on DA 2404 and compare them withthe allowable damage limits given inthis section. Select the set ofallowable damage limits which are nextlarger than the measured damage, deter-mine the corresponding condition.Consider whether damage could result inflight failure of other elements.Attempt to visualize what effect largedefections of damaged member will haveon adjacent structure.

c. Decide on whether repair can bedeferred or whether damage should befixed and what the condition of deferredor repaired damage would be.

4-16


Figure 4-8. OH-58 Helicopter

4-17

PROFILEBL - BUTT LINE

FS - FUSELAGE STATION

WL - WATERLINE

BS - BOOM STATION (UNDERLINED)

CENTER TAILROTOR BEARING HANGER.● TANGENCY POINT.

CONTOURS IN BOOM STATIONS ARECIRCLES. RADIUS AT 31.87 IS 7.3555"RADIUS AT 182.405 IS 3.286". TAPER'OF BOOM IS 0.02703" PER INCH. BOOMSTATION IS 90° TO HORIZ C BOOM.

TM 55-1520-228-BD

4-18

AIRFRAME

Figure 4-9. Airframe Reference Lines


Figure 4-10. Cockpit

4-19


Figure 4-11. Fuselage Pylon Support Structure (Sheet 1 of 5)

4-20



4-21



4-22


FS130

FUSELAGE STA 130BULKHEAD

FS117.71

WL 21.00


4-23



4-24


Figure 4-12. Upper and Lower Shell Structure

4-25


Figure 4-13. Aft Fuselage Structure

4-26


Figure 4-14. Tail Boom

4-27


Figure 4-15. Cowling and Firewalls

4-28


d. Determine the priority of thevarious required repairs based on repairtime, difficulty of repair, resourcesavailable, tactical situation, and needfor the aircraft, etc. The longestrepair time normally is given thehighest priority and is most critical.

4-13. ALLOWABLE DAMAGE LIMITS. Damagelimits are calculated on the basis ofthe OH-58 structural analysis and tendto be conservative. Assessors usingdamage limits to prepare damageassessments should consider them asguides and balance the damage limitsagainst the judgment resulting fromtheir own experience.

a. Damage limits are tabulated inTables 4-2 thru 4-7 for most primarystructure. If a damaged member is notcovered in this manual and the damageappears to exceed authorized limits,classify the member as unserviceable.

b. A component that shows signs ofsevere overstress such as twisting orbuckling or heat damage should betreated as failed.

c. A component should be repaired ifthe failed component can overstressother systems.

d. Evaluation of Damage to Caps,Longerons, and Stringers. Classifycaps,longerons, and stringers as failedif any of-the following conditionsexist:

(1) Damage exceeds limitstabulated in Tables 4-2 thru 4-7.

(2) There is damage in four ormore locations within a length of threefeet.

(3) Fasteners securing the com-ponent to other major components aresheared, pulled-through, or missing atone or more locations.

(4) Three or more fasteners nextto each other, which join a cap,longeron, and stringer to the web, aresheared, pulled-through or missing.

(5) Twenty percent or more of thecomponent to web fasteners are similarlydamaged.

(6) Angles and clips securing thecomponent to another structure areseverely damaged or failed.

e. Evaluation of Damage to MachinedFittings. Classify a fitting as failedif any of the following conditions exist:

(1) Damage to the fitting exceedsthe limits contained in Tables 4-2thru 4-7, or if damage is not tabulatedand exceeds 20 percent of the structuralsection in any one location.

(2) One or more fasteners con-necting the fitting to a structure or toan aircraft component are bent, sheared,stripped, or loose.

f. Evaluation of Splices, Straps,Doublers, and Gussets. Damage to asplice, strap, doubler, and gusset willbe evaluated as part of the elements towhich it attaches. Classify a splice,strap, doubler, or gusset as failed ifany of the following conditions exist:

(1) Damage exceeds the limits con-tained in Tables 4-2 thru 4-7, or ifdamage is not tabulated and exceeds 20percent of the structural section inany location.

(2) The part has significantdamage at the intersection of the twomembers it connects.

(3) Fasteners securing the part toa structural member(s) are sheared,pulled-through, or missing at two ormore adjoining locations.

(4) More than 20 percent of thetotal number of fasteners are similarlydamaged.

4-29


g. Evaluation of Damage to Skin andWeb Panels. Classify a skin or webpanel as failed if any of the followingconditions exist:

(1) Damage exceeds the limits con-tained in Tables 4-2 thru 4-7, or ifdamage is not tabulated and exceeds 25percent of the panel area.

(2) Damage to one panel is locatedwithin 3 inches of damage in an adjoin-ing panel.

(3) The panel is severely deformedor buckled.

(4) Damage to a panel exceeds thedamage limit. The damage extends acrossa stringer, frame, or former in an ad-joining panel. Classify that panel asfailed even if its damage is withinlimits.

(5) The panel is on the outside ofthe aircraft where the damage is exposedto aerodynamic forces that can producepeeling or tearing of the structure inflight.

(6) Fasteners securing the panelare sheared, pulled-through, or missingat three or more adjoining locations.

(7) Twenty percent or more of thetotal number of fasteners are similarlydamaged.

h. Evaluaton of Damage to Honeycomb-Sandwich Panels. Classify a honeycomb-sandwich structure as failed if any ofthe following conditions exist:

(1) Damage exceeds limitstabulated in Tables 4-2 thru 4-7.

(2) The panel is damaged to theextent that it cannot support the weightof personnel, cargo, or equipment forwhich it was designed.

(3) The panel is on the outside ofthe aircraft where it is exposed toaerodynamic forces, and the damage is

4-30

oriented so as to produce peeling ortearing of the structure in flight.

(4) The panel is secured by mecha-nical fasteners. Three or moreadjoining fasteners are sheared, pulled-through, or missing.


i. Evaluation of Damage to SheetMetal Ribs, Formers, Intercoastals, andChannels. Classify a rib, former,intercostal, or channel as failed ifany of the following conditions exist:

(1) Damage exceeds the limits con-tained in Tables 4-2 thru 4-7, or ifdamage is not tabulated and exceeds 25percent of the structural section.

(2) Fasteners securing the com-ponent are sheared, pulled-through, ormissing in three or more adjoining loca-tions.


j. Evaluation and Damage to Hatches,Doors, and Door Jambs. Classify adamaged hatch, door, or door jamb asfailed if any of the following con-ditions exist:

(1) Damage exceeds limitstabulated Tables 4-2 thru 4-7.

(2) Damage to the hatch, door, ordoor jamb prevents it from being securedadequately to the airframe.

(3) Hinges and latches are damagedand in danger of becoming unserviceablein flight.

(4) The hatch or door shows signsof severe overstress such as buckling ormisalignment.

Table 4-2. Dam

COMPONENT/ LOCATIONMEMBER FS WL BLConsole, 1.00- 20.00- 5.06R-Forward 32.75 44.50 3.06L

1.00- 20.00- 5.06R-32.75 44.50 3.06L32.75- 21.00- 5.06R-55.10 32.50 3.06L32.75- 23.39- 5.06R-44.00 32.50 3.06L32.75- 21.00- 5.06R-44.00 23.39 3.06L

Honeycomb 44.00- 21.00- 5.06R-Panel 57.10 32.50 3.06L

44.00- 21.00- 5.06R-57.10 32.50 3.06L

InstrumentPanel 21.25- 44.15- 5.02R-Shroud 37.57 51.95 3.02LFrontSeat 21.00-Support 57.11 30.41Pilot's &Copilot's 57.11- 19.45L-Seat 74.54 30.41 22.15RCenterBulkhead 30.29-Section 73.04 54.89CenterBulkhead 21.00- 10.65-Section 73.04 30.29 17.31L&RPilot’s &Copilot’s 73.04 30.29Collective 21.00-Jackshaft 73.04 30.29Pedestal 55.14- 20.00- 5.06R-Structure 73.04 30.17 3.06L

age Limits Forward Fuselage - Condition IDAMAGE LIMITS

ELEMENT CAP/FLANGE SKIN/WEBCD ' CL' N WL ' NOTES/CAUTIONS

Caps, Stiffeners, (D’=NxCL) (D'=NxWL)Doublers 1.05 2.10 10

N

Skins/Webs 2.5 5Caps, Stiffeners,Doublers 0.15 0.30 10

Skins/Webs 2.5 5No Damage

Skin Allowed

Honeycomb Panel 7.50 5

Panel Edges 0.20 0.40 10

Brace 1.25 2.50 10

Honeycomb No DamageBulkhead Allowed


Web 10.0 5 Behind Pilots

Vertical Sum of DamageStiffeners 2.0 4.0 - on All ElementsAft AttachmentAngle No Damage PermittedSupport BracketChannel 0.70 1.50 10

Webs 0.75 5

TM 55-1520-228-BD

AIRFRAME

4-31

T M

55 -1

520-228 -B

DTable 4-2. Damage Limits Forwar d Fuselage — C ondition I (Cont)

DAMAGE LIMITSLOCATION

CAP / FLANGE SKIN / WEBCOMPONENT /MEMBER

FS WL BLELEMENT

CD’ CL’ N WL’ N

NOTES /CAUTIONS

(D’=N x CL) (D’=N x WL)Pedestal Structure 55.14-73.04

20.00-30.17

5.06R-3.06L

Caps/Stiffeners

0.65 1.30 10Lower Shell 36.00-

73.0420.00-25.25


36.00-73.04 20.00

Inserts for Cyclic &Pedal Controls No Damage Within 3” Radius of Insert

73.00 20.0012.16&14.58L&R

Forward LandingGear Attachments One Damaged Insert Permitted

Center Post 73.00-87.85

20.00-72.00

3.00L-3.00R

Caps 0.25 0.50 10

73.00-87.85

27.48-72.00

3.00L-3.00R

Side Webs andDoublers 2.25 5

74.52-81.30

54.50-72.00

3.00L-3.00R

Web, Front 0 —

80.00-87.85

62.00-72.00

3.00L-3.00R

Splices 0 - -

73.00-87.85

20.00-72.00

3.00L-3.00R

Stiffeners 0.50 1.00 10

Passenger Seat 96.44-114.76

29.92-31.42

24.14L-24.14R

Honeycomb SeatPanel 4.25 5

No Damage Within3” of Gun Mounts(If used)

96.44-114.76

24.70-29.92

23.08L&R Honeycomb SidePanels 1.5 5

96.4420.00-29.92

23.08L-23.08R

Honeycomb FrontPanel 4.0 5

96.44-114.76

20.00-29.92

23.08L-23.08R

Angles, Side, FrontTop, Bottom 0.25 0.50 10

Gun Mounts103.76 30.25

0.00&23.00L

Fittings andFasteners No Damage Permitted (If Used)

Depression StopAttachment 104.55 30.25 5.85L

Honeycomb Panel No Damage Permitted Within 3” Radiusof Attachments

4-32

AIR

FR

AM

E

TM

55-1520-22 8-B

D

Table 4-2. Damage Limits Forwar d Fuselage — C ondition I (Cont)



FS WL BL

ELEMENT


NOTES /CAUTIONS

(D’=N x CL) (D’=N x WL)Passenger SeatBack Bulkhead

114.79-122.20

31.42-72.00

Flanges, Angles,Caps, Splices, Clips

No Damage Permitted

117.90-122.20

48.25-72.00

Web 1.10 5

115.10-117.70

35.39-49.98

17.80L17.80R

Honeycomb DoorAssembly 3.00 5

114.76-117.70

31.42-49.98

Honeycomb PanelAssembly

1.501.50

55

Bulkhead FS130,Upper 130

51.72-72.00

Inboard, OutboardFrame Caps 0.30 0.60 10

13051.72-72.00

Frame Webs 2.40 5

13051.72-72.00

Clips, Splices,Supports, Flanges 0.30 0.60 10

Bulkhead FS130,Lower 130

29.70-51.52


13020.00-29.70


Aft CabinEnclosure

120.00-130.00

50.04-69.00 20.55L&R

Inner Skin andDoublers 3.70 5

117.71-130.00

50.04-67.20 25.25L

Outer Skin 6.00 5

117.71-130.00

50.04-67.20 25.25R

Outer Skin and DoorPanel 6.00 5

117.71-130.00

50.00-72.00

25.25L&R

IntercoastalsBetween Inner &Outer Skin

1.50 5

117.71-130.00

50.04-72.00 25.25L&R

Angles, Supports,Flanges, Stiffeners 0.50 1.00 10

4-33

AIR

FR

AM

E

T M

55 -1

520-228 -B

DTable 4-2. Damage Limits Forwar d Fuselage — C ondition I (Cont)



FS WL BLELEMENT


NOTES /CAUTIONS

(D’=N x CL) (D’=N x WL)Aft CabinEnclosure

120.00-130.00 63.71 20.00L

Gun Mount Channel

1.00 2.00 10Pylon Support 98.80 73.93 7.52L&R Forward Support No Damage Allowed

123.62 71.92 6.25L&R Aft Support No Damage Allowed

Cabin Roof Beam 80.46-130.00

67.92-71.96 3.00L&R

Beam, Left and Right No Damage Allowed

101.67&123.62

67.92-71.96

0 Bulkheads BetweenBeams No Damage Allowed

120.9067.92-71.96

3.00L-3.00R

Bulkhead Skin andDoubler 2.00 5

80.46-130.00 67.92

3.00L-3.00R

Bottom Skin andAccess Cover 0.75 5

Lower Cabin Shell 73.18-113.00

20.00-25.25

18.40L&R-Outboard

Radius and Edge ofHoneycomb Panel 1.00 5

73.18-113.00

20.00

18.40L-18.40R

Honeycomb Panel6.30 5

No DamageWithin 3” Radiusof Inserts

113.00-130.00

20.00-54.65


No DamageWithin 3” Radiusof Inserts

96.44 20.00 Splice 0.75 1.50 10

36.00-130.00

20.00-54.65

Frames, Angles,Stiffeners 0.50 1.00 10

Upper Cabin RoofShell

54.48-82.86

Top Skin 3.00 5

82.86-125.00

Honeycomb Panels 3.00 5

120.40-130.00

14.12L&R-Outboard

Honeycomb Panels 2.50 5

125.00-130.00

14.12L-14.12R

Titanium Panel 2.50 5

4-34

AIR

FR

AM

E

TM

55-1520-22 8-B

D

Table 4-2. Damage Limits Forwar d Fuselage — C ondition I (Cont)



FS WL BL

ELEMENT


NOTES /CAUTIONS

(D’=N x CL) (D’=N x WL)Upper Cabin RoofShell

54.48-130.00

Flanges, Formers,Stiffeners, Supports

0.60 1.20 10

Landing Gear 73.00&130.00

18.30&20.75

13.30L&R&

10.25L&R

Support FittingFlanges Damage Allowed on One Flange

130.00 20.75 10.25L&R Cross Tube Aft Strap 0.31 0.62 -

73.00 18.30 13.30L&R Cross Tube ForwardStrap 0.10 0.20 -

73.00&130.00

18.30&20.75

13.30L&R&

10.25L&R

Back-Up SupportsNo Damage Allowed

73.00&130.00

18.30&20.75

13.30L&R&

10.25L&R

AttachmentFasteners and Inserts

Damage Allowed OnOne Fastener & Insert

Per Fitting

Jacking &Tiedown Fittings

Fitting Damage Limited ByJacking Tiedown

Requirements

Anti-TorqueSupport 35.66 21.00

5.04L-3.04R

Fitting No Damage Allowed

CollectiveJackshaft BearingSupport 73.12 28.62 1.50L

FittingNo Damage Allowed

Anti-TorqueSupport Fitting 78.95 23.83 3.06L


4-35

AIR

FR

AM

E

T M

55 -1

520-228 -B

DTable 4-3 . Dam age Limits Aft Fuselage — Condition I



FS WL BLELEMENT


NOTES /CAUTIONS

(D’=N x CL) (D’=N x WL)Upper Longeron 130.00-205.00

72.00-72.93

14.12-4.72L&R

Channel

No Damage Allowed

130.00&167.00

Splice No Damage Allowed

205.00 Tail Boom Attach Fittings No Damage AllowedCenter Longeron 130.00-

206.3551.67-61.76

25.5-2.79L&R

Angle and Channel No Damage Allowed

130.00 51.67 Splice No Damage Allowed

206.35 61.76 Tail Boom Attach Fittings No Damage AllowedLower Longeron 130.00-

192.8429.40-44.50

22.50-1.10L&R

Angle No Damage Allowed


Aft Fuselage 130.00-206.35

Lower LongeronUpward


130.00-206.35

Lower Longeronto UpperLongeron

Skin3.0 5

130.00-206.35


Doublers 3.0 5

130.00-206.35


Clips Same Limits As Attaching Structure

Tail Boom Access Door 192.84-205.76

73.34-61.76

Skin 8.0 5

Deck 179.92-205.76 72.00

8.33L-8.33R

skin 3.0 5

Oil Cooler 167.00-179.92

72.00

10.18L-10.18R

Honeycomb SupportPanel 2.0 5

No DamageWithin 3” ofInserts

171.50 72.00 0 Pan & Drain No Damage Allowed

4-36

AIR

FR

AM

E

TM

55-1520-22 8-B

D

Table 4-3 . Dam age Limits Aft Fuselage — Condition I (Cont)



FS WL BL

ELEMENT


NOTES /CAUTIONS

(D’=N x CL) (D’=N x WL)Anti-Torque Support 179.92-181.62

58.27-73.37

0.88R

Support and Fittings

No Damage Allowed

Engine Pan 130.00-167.00 71.74

14.12L-14.12R

Horizontal Stiffeners 1.00 2.00 10

130.00-167.00 71.74

14.12L-14.12R

Web & Drain No Damage Allowed

130.00-167.00 71.74

14.12L-14.12R

Spot Weld Damage 1/3 of Welds May Be Damaged

130.00-167.00 71.74

14.12L-14.12R

Doublers, SplicesVertical Stiffeners 0.75 1.50 10

Canted Web 130.00-192.84

51.67-59.98

25.00L&R-7.00L&R


130.00-192.84

51.67-59.98

15.00L&R-7.00L&R

Web 4.75 5

Shear Web 192.84-206.35 60.00

7.00L&R-4.00L&R


192.84-206.35 60.00

7.00L&R-4.00L&R

Webs 3.00 5

ElectricalCompartment Floor

130.00-167.00

29.47-34.46

Inserts Damage Allowed to One Insertin Each Group of Four

130.00-167.00

29.47-34.46

Honeycomb10.00 5

No Damage Within2” of EffectiveInserts

Bulkheads 142, 154, 167,179, 192

Frame Section 0.75 1.50 10

142, 154, 167,179, 192

Stiffeners, ClipsDoublers 0.50 1.00 10

142, 154, 167,179, 192

Splices No Damage Allowed4-37

AIR

FR

AM

E

T M

55 -1

520-228 -B

DTable 4-3 . Dam age Limits Aft Fuselage — Condition I (Cont)



FS WL BLELEMENT


NOTES /CAUTIONS

(D’=N x CL) (D’=N x WL)Bulkhead

205.74

Frame Section

0.40 0.80 10

205.74 Angles, Clips 0.50 1.00 10

Engine MountSupport 130.00 8.465L&R

Back-Up Structure No Damage Allowed

130.00 3.50L&R Fitting No Damage Allowed

142.33 72.00 12.96L&R Fitting No Damage Allowed

4-38

TM

55-1520-228-BD

Table 4-4. Damage Limits Tail Boom and Landing Gear — Condition I



BS WL BL

ELEMENT


NOTES /CAUTIONS

(D’=N x CL) (D’=N x WL)Tail Boom 31.94-42.59

Intercoastals

No Damage Allowed

31.92 Attachment Fittings No Damage AllowedAt any

Circumference31.87-164.10

Skin

3.0 5

No DamageAllowed BS164.10-182.40

31.87, 42.59,79.82, 98.29,116.84, 150.22

BulkheadsNo Damage Allowed

174.10-182.40

Bulkheads 0.85 1.70 10

174.10-182.40

Fin Supports 0.17 0.34 10

174.10-182.40

Gearbox Mounting Plate No Damage Allowed

AIR

FR

AM

E

T M

55 -1

520-228 -B

DTable 4-4. Damage Limits Forward Fuselage — Condition I



FS WL BL

ELEMENT


NOTES /CAUTIONS


Bell Crank Support

No Damage Allowed

31.87-182.40

Driveshaft Support &Hangers No Damage Allowed

Stabilizer 84.57 Spar0.70 1.40 10

Fin Honeycomb Panels 2.0 5

4 -3

9

TM

55-1520-228-BD

Table 4-5. Damage Limits Forward Fus elage — Condition II



FS WL BL

ELEMENT


NOTES /CAUTIONS

(D’=N x CL) (D’=N x WL)Fin Fin to AntennaAttaching Flanges

1.20 2.40 10

Fin to Boom Inserts No Damage Within 3” of Inserts

Tail Skid Tube FittingNo Damage Restrictions

Landing Gear Skid Tube 2.00 5

Fwd and Aft CrossTubes No Damage Allowed

Forward Console 1.00-32.75

20.00-44.50

5.06R-3.06L

Caps, Stiffeners,Doublers 1.10 2.20 5

1.00-32.75

20.00-44.50

5.06R-3.06L

Skins/Webs 4.50 5

32.75-55.10

21.00-32.50

5.06R-3.06L

Caps, Stiffeners,Doublers 0.65 1.30 5

32.75-44.00

23.39-32.50

5.06R-3.06L

Skins/Webs 4.50 5

32.75-44.00

21.00-23.39

5.06R-3.06L

Skin 1.00 5

HoneycombPanel

44.00-57.10

21.00-32.50

5.06R-3.06L


AIR

FR

AM

E

T M

55 -1

520-228 -B

DTable 4-5. Damage Limits Forward Fuse lage — Condition II (Cont)



FS WL BL

ELEMENT


NOTES /CAUTIONS

(D’=N x CL) (D’=N x WL)HoneycombPanel

44.00-57.10

21.00-32.50

5.06R-3.06L

Panel Edges

0.35 0.70 5

Instrument PanelShroud

21.25-37.56

44.15-51.95

5.02R-3.02L

Brace

1.50 3.00 5

Front SeatSupport

57.11

21.00-30.41

HoneycombBulkhead 1.05 5

Does Not IncludeManufacturer’sHoles

Pilot’s & Copilot’sSeat

57.11-74.54 30.41

19.45L-22.15R


Center BulkheadSection 73.04

30.29-54.89

Web 12.00 5

73.0421.00-30.29

10.64-17.31L&R

Vertical Stiffeners 2.20 4.40 -

Pilot’s & Copilot’sSeat 73.04 30.29

Aft Attachment Angle 0.70 1.40 5

CollectiveJackshaft 73.04

21.00-30.29

Support BracketChannel 1.00 2.00 5

PedestalStructure

55.14-73.04

20.00-30.17

5.06R-3.06L

Webs 1.10 5

55.14-73.04

20.00-30.17

5.06R-3.06L

Caps/Stiffeners 0.85 1.70 5

Lower Shell 36.00-73.00

20.00-25.25


36.00-73.00 20.00

Inserts for cyclic andPedal Controls

No Damage in One Set of Controls Within3” Radius of Inserts

73.00 20.00

12.16 &14.58L&R

Forward LandingGear Attachments Two Diagonal Inserts May Be Damage

Center Post 73.00-85.85

20.00-72.00

3.00L-3.00R

Caps 0.75 1.50 5

4-40

AIR

FR

AM

E

TM

55-1520-22 8-B

D

Table 4-5. Damage Limits Forward Fuse lage — Condition II (Cont )



FS WL BL

ELEMENT


NOTES /CAUTIONS

(D’=N x CL) (D’=N x WL)Center Post 73.00-87.85

24.48-72.00

3.00L3.00R

Side Webs andDoublers

4.50 5

74.52-81.30

54.50-72.00

3.00L3.00R

Front Web 2.50 5

80.00-87.85

62.00-72.00

3.00L-3.00R

Splices 0.75 1.50 5

73.00-87.85

20.00-72.00

3.00L-3.00R


Passenger Seat 96.44-114.57

29.92-31.42

24.14L-24.14R

Honeycomb SeatPanel 10.00 5

No DamageWithin 3” of GunMount (If Used)

96.44-114.76

24.70-29.92

23.08L&R Honeycomb SidePanels 2.00 5

96.44 20.00-29.92

23.08L-23.08R

Honeycomb FrontPanel 4.5 5

96.44-114.76

20.00-29.92

23.08L-23.08R

Angles, Side, Front,Top, bottom 0.60 1.20 5

Gun Mounts 103.76 30.25 0.00 &23.00L

Fittings andFasteners No Damage Permitted (If Used)

Depression StopAttachment

104.55 30.25 5.85L Honeycomb Panel No Damage Permitted Within 1-1/2”Radius of Attachments

Passenger SeatBack Bulkhead

114.79-122.20

31.42-72.00

Flanges, Angles,Caps, Splices, Clips 0.50 1.00 5

117.90-122.20

48.25-72.00

Web 1.40 5

115.10-117.70

35.39-49.98

17.80L-17.80R

Honeycomb DoorAssembly 6.00 5

114.76-117.70

31.42-49.98

Honeycomb PanelAssembly 2.00 54-41

AIR

FR

AM

E

T M

55 -1

520-228 -B

DTable 4-5. Damage Limits Forward Fuse lage — Condition II (Cont)



FS WL BL

ELEMENT


NOTES /CAUTIONS

(D’=N x CL) (D’=N x WL)Bulkhead FS130,Upper

130

51.72-72.00

Inboard, OutboardFrames, Webs

0.60 1.20 5

13051.72-72.00

Frame, Webs 3.00 5

13051.72-72.00

Clips, SplicesSupports, Flanges 0.60 1.20 5

Bulkhead, FS130,Lower 130

29.70-51.52


13020.00-29.70


Aft CabinEnclosure

120.00-130.00

50.04-69.00 20.55L&R

Inner Skin andDoublers 5.30 5

117.71-130.00

50.04-67.20 25.25L

Outer Skin 7.50 5

117.71-130.00

50.04-67.20 25.25R

Outer Skin and DoorPanel 7.50 5

117.71-130.00

50.0072.00

25.25L&R

IntercoastalsBetween Inner &Outer Skin

2.00 5

117.71-130.00

50.04-72.00 25.25L&R

Angles, Support,Flanges, Stiffeners 0.70 1.40 5

Aft CabinEnclosure

120.00-130.00

63.7120.00L

Gun Mount Channel 1.50 3.00 5

Pylon Support 98.80 73.93 7.52L&R Forward Support No Damage Allowed

123.62 71.92 6.25L&R Aft Support No Damage Allowed

Cabin Roof Beam 80.46-130.00

67.92-71.96 3.00L&R

Beam, Left and Right No Damage Allowed

101.67&123.62

67.92-71.96

0 Bulkheads BetweenBeams No Damage Allowed

4-42

AIR

FR

AM

E

TM

55-1520-22 8-B

D

Table 4-5. Damage Limits Forward Fuse lage — Condition II (Cont)



FS WL BL

ELEMENT


NOTES / CAUTIONS

(D’=N x CL) (D’=N x WL)Cabin Roof Beam

120.90

67.92-71.96

3.00L-3.00R

Bulkhead Skin andDoublers

2.75 5

80.46-130.00 67.92

3.00L-3.00R

Bottom Skin and AccessCover

1.00 5

Lower Cabin Shell 73.18-113.00

20.00-25.25

18.40L&R-Outboard

Radius and Edge ofHoneycomb Panel

1.50 5

73.18-113.00 20.00

18.40L18.40R


No Damage Within 3”Radius of Inserts

113.00-130.00

20.00-54.65


No Damage Within 3”Radius of Inserts

96.44 20.00 Splice 1.50 3.00 5

36.00-130.00

20.00-54.65

Frames, Angles Stiffeners0.75 1.50 5

Upper Cabin RoofShell

54.48-82.86

Top Skin4.50 5

82.86-125.00

Honeycomb Panels4.50 5

120.40-130.00

14.12L&R-Outboard

Honeycomb Panels3.00 5

125.00-130.00

14.12L-14.12R

Titanium Panel3.00 5

54.48-130.00

Flanges, Formers,Stiffeners, Supports

0.75 1.50 5

Landing Gear 73.00&130.00

18.30&20.75

13.30L&R &10.25L&R

Support Fitting FlangesDamage Allowed on Two Diagonal Tabs

130.00 20.75 10.25L&R Cross Tube Aft Strap 0.63 1.26 5

73.00 18.30 13.30L&R Cross Tube Forward Strap 0.35 0.70 5

73.00&130.00

18.30&20.75

13.30L&R &10.25L&R

Back-Up SupportNo Damage Allowed

4-43

AIR

FR

AM

E

TM

55-1520-22 8-B

D

Table 4-5. Damage Limits Forward Fuse lage — Condition II (Cont)



FS WL BL

ELEMENT


NOTES /CAUTIONS

(D’=N x CL) (D’=N x WL)Landing Gear 73.00&130.00

18.30&20.75

13.30L&R&

10.25L&R

Attachment Fastenersand Inserts

Damage Allowed on One Fastener andInsert Per Fitting

Jacking & TiedownFittings

Fitting Damage Limited By Jacking and TiedownRequirements

Anti-TorqueSupport 35.66 21.00

5.04L-3.04R


CollectiveJackshaft BearingSupport 73.12 28.62 1.50L

FittingNo Damage Allowed

Anti-TorqueSupport Fittings 78.95 23.83

3.06L Fitting No Damage Allowed

4 -44

Table 4-6. Damage Limits Aft Fuse lage — Condition II



FS WL BL

ELEMENT


NOTES /CAUTIONS

(D’=N x CL) (D’=N x WL)Upper Longeron 130.00-205.00

72.00-72.93

14.12-4.72L&R

Channel

1.50 3.00 5

130.00&167.00

Splice No Damage Allowed

205.00Tail Boom AttachFittings No Damage Allowed

Center Longeron 130.00-206.35

51.67-61.76

25.50-2.79L&R

Angle and Channel 0.90 1.80 5

130.00 51.67 Splices No Damage Allowed

206.3561.76 Tail Boom Attach

Fittings No Damage Allowed

Lower Longeron 130.00-192.84

29.40-44.50

22.50-1.10L&R

Angle 0.85 1.70 5


AIR

FR

AM

E

TM

55-1520-22 8-B

D

Table 4-6. Damage Limits Aft Fuse lage — Condition II (Cont)



FS WL BL

ELEMENT


NOTES /CAUTIONS

(D’=N x CL) (D’=N x WL)Aft Fuselage 130.00-206.25

LongeronUpward

Stiffeners0.75 1.50 5

130.00-206.25

LowerLongeronto UpperLongeron

Skin

3.75 5

130.00-206.35

LowerLongeronUpward

Doublers3.75 5

130.00-206.35

LowerLongeronUpward

ClipsSame Limits as Attaching Structure

Tail Boom Access 192.84-205.76

73.34-61.76

Skin 11.0 5

Deck 179.92-205.76 72.00

8.33L-8.33R

Skin 3.75 5

Oil Cooler 167.00-179.92 72.00

10.18L-10.18R

Honeycomb SupportPanel 3.00 5 No Damage Within

2” of Inserts171.50 72.00 0 Pan & Drain No Damage Allowed

Anti-Torque Support 179.92-181.62

58.27-73.37

0.88R Support & Fittings No Damage Allowed

Engine Pan 130.00-167.00 71.74

14.12L14.12R

Horizontal Stiffeners 1.20 2.40 5

130.00-167.00 71.74

14.12L14.12R

Web & Drain No Damage Allowed

130.00-167.00 71.74

14.12L-14.12R

Spot Weld Damage 1/2 of Welds May Be Damaged

130.00-167.00 71.74

14.12L-14.12R

Doublers, SplicesVertical Stiffener 0.85 1.70 5

Canted Web 130.00-192.84

51.67-59.98

25.00-7.00L&R


130.00-192.84

51.67-59.98

25.00-7.00L&R

Web 5.40 54-45

AIR

FR

AM

E

T M

55 -1

520-228 -B

DTable 4-6. Damage Limits Aft Fuse lage — Condition II (Cont)



FS WL BLELEMENT


NOTES /CAUTIONS

(D’=N x CL) (D’=N x WL)Shear Web 192.84-206.35

60.00

7.00-4.00L&R

Stiffeners

0.40 0.80 5

192.84-206.35

60.00 7.00-4.00L&R

Webs 3.60 5

ElectricalCompartmentFloor

130.00-167.00

29.47-34.46

Inserts Damage Limited to Two Inserts to EachGroup of Four

130.00-167.00

29.47-34.46

Honeycomb 15.0 5 No DamageWithin 2” of

Effective InsertsBulkheads 142, 154

167, 179192

Frame Section1.10 2.20 5

142, 154167, 179192

Stiffeners, Clips,Doublers 0.70 1.40 5

142, 154167, 179192

SplicesNo Damage Allowed

Bulkhead 205.74 Frame Section 1.50 3.00 5

205.74 Angles, Clips 0.70 1.40 5

Engine MountSupport 130.00

8.465L&R Back-Up Structure No Damage Allowed

130.00 3.50L&R Fitting No Damage Allowed

142.33 72.00 12.96L&R Fitting No Damage Allowed

4-46

AIR

FR

AM

E

TM

55-1520-22 8-B

D

Table 4-7. Damage Limits Tail Boom and Landing Gear — Condition II



FS WL BL

ELEMENT


NOTES /CAUTIONS


IntercoastalsNo Damage Allowed

31.92 Attachment Fittings No Damage AllowedAt Any Circumference31.87-

164.10Skin

6.00 5No DamageAllowedBS164.10-182.40

31.87,42.59,79.82,98.29,116.84,150.22

Bulkheads

1.00 2.0 0 5

174.10-182.40

Bulkheads 1.05 2.10 5

174.10-182.40

Fin Supports 0.50 1.00 5

174.10-182.40

Gearbox MountingPlate No Damage Allowed

174.10-182.40

Bell Crank Support No Damage Allowed

31.87-182.40

Driveshaft Supportand Hangers No Damage Allowed

Stabilizer 84.57 Spar 1.50 3.00 5

Fin Honeycomb Panels 4.50 5

Fin to AntennaAttaching Flanges 2.60 5.20 5

Fin to Boom No Damage Within 3” of InsertsTail Skid Tube Fitting No Damage Restrictions

Landing Gear Skid Tube 3.50 5

Fwd & Aft CrossTubes 1.50 54-47

AIR

FR

AM

E


(5) There are large holes orcracks in an area of the door or hatchexposed to the windstream, and peelingor tearing of the material in flight isprobable.

(6) Fasteners holding major com-ponents of the hatch, door, or door jambtogether are sheared, pulled-through, ormissing at three or more adjoininglocations.


k. Evaluation of Damage to Fairingsand Cowlings. Classify a damagedfairing or cowling as failed if any ofthe following conditions exist:

(1) Damage to the fairing andcowling or its attaching structure pre-vents it from being adequately securedto the airframe.

(2) The fairing and cowling showssigns of severe overstress such ascrushing, buckling, or misalignment.

(3) Tracks, rollers, hinges, orlatches are damaged in danger ofbecoming unserviceable in flight.

(4) Fasteners securing the fairingand cowling are sheared, stripped,pulled-through, or missing at three ormore adjoining locations.


(6) There are large cracks orholes in an area of the fairing andcowling exposed to the windstream, andpeeling or tearing of the material inflight is probable.

(1) The firewall shows sign ofsevere overstress such as buckling andmisalignment.

(2) Fasteners securing the fire-wall to the upper deck structure aresheared, stripped, pulled-through, ormissing at three or more adjoining loca-tions.


(4) Damage to the supporting frame-work causes the firewalls to be looseand subject to collapsing in flight.

(5) There are large holes orcracks in the firewall that would pre-vent the firewall from containing afire.

m. Assessing the Effect of StructuralDamage on Other Aircraft Systems.

(1) The assessment standards pro-vided basically concern the air-worthiness and flight capability of theOH-58 airframe. However, every memberof the airframe has a structural and/orfunctional purpose. Even those memberswhich are unessential to airworthinessmay have an important function relatedto the integrity and performance ofother aircraft systems and components.Some of these effects have been con-sidered and are reflected in theassessment standards.

(2) The assessor is responsiblefor working with other specialists todetermine if damage to airframestructures will overstress, damage, ordegrade the performance of other systemcomponents. All of the system hardwarenear the damage should be evaluated forthese possible effects. Among the typesof conditions to consider are as follows:

1. Evaluation of Damage to Firewalls.Classify a damaged firewall as failed ifany of the following conditions exist:

4-48

(a) Structural movement whichmight change the location or alignmentof a component. Controls and drive-shafts will be particularly critical.

(b) Structural damage whichcould affect the security of wirebundles and fluid lines, causing them tovibrate, chafe, and fatigue duringflight.

(c) Damaged structure whichmight interfere with the free travel ormovement of a system component duringoperation.

(3) If the assessor determinesthat structural damage will or mightcreate any of the above conditions,


classify the structure as failed even ifthe physical damage is within allowablelimits.

4-14. BDAR REPAIR PROCEDURE INDEX.

PARA.

Skin/Stiffener Damage. . . . . 4-16Cap, Skin, Web, Doubler

Damage. . . . . . . . . . . 4-17Cap or Longeron Damage . . . . 4-18Frame, Bulkhead, Skin and

Stringer Damage. . . . . . . 4-19Honeycomb Core Floor or

Panel Damage . . . . . . . . 4-20Windshield/Window Damage . . . 4-21Tail Boom Skin Damage . . . . 4-22

Section II. EXPEDIENT STRUCTURAL REPAIRS

4-15. GENERAL.

a. Many of these expedient repairswill restore the airframe to condition1. Inspection for damage growth willgenerally be required after everyflight, and damage should be repairedas soon as practical by standard main-tenance procedures.

b. Multiple Damage. Special atten-tion should be given to structural com-ponents which have sustained damage inmultiple locations. It is essentialthat damage to an individual structuralitem not be considered by itself. Suit-able repair will often depend on thecondition of the adjacent structure. Insome cases, undamaged adjacent structuremay satisfactorily take the load of thedamaged item. Since time is an over-riding consideration on the battlefield,BDAR airframe repairs are usually per-formed on the outside of the aircraft tosave the time required to gain access tothe interior. If, however, access to theinterior damaged structure is alreadyavailable, inside BDAR repairs may bemade.

c. Fasteners. BDAR can be carriedout using any form of fastening device,which is available at the time (e.g.,nuts, bolts, rivets, etc.), as long asstrength requirements are met. Useaccepted practices regarding fasteneredge distance and spacing. The faste-ners used in a single repair should beof the same type.

d. Metal Selection. All repairpatches should be manufactured frommaterial of the same or similar specifi-cation as the damaged area but at leastone gauge or 10 percent thicker. Whenrequired repair materials are una-vailable, substitutions can often bemade to produce a desired strength.Table 4-8 cross lists various types ofmetal and instructions on how to substi-tute one type of metal for another.Alternate repair materials can beobtained from scrapped aircraft. It isalso permissible to fabricate fromthinner gauge material and use multiplethickness.

4-49

4-50

Table 4-8. Metal Substitution Chart TM 55-1520-228-BDAIRFRAME


NOTE

Steel and aluminum are incom-patible materials and normallyrequire special precautions.However, for BDAR, this is anacceptable usage.

Refinements to patch repairs,such as countersunk fasteners,chamfered edges, anti-corrosivetreatment, and radius cornersof the patches are unnecessary.

e. External patch repairs generallywill meet strength criteria for effec-tive BDAR. Sometimes these repairs musttake into consideration the clearance ofmoving parts (e.g., control surfaces,doors, etc). In low stress areas,patches may only be necessary to provideaerodynamic shape to prevent ram aireffect or to keep water out. Damage inthese areas can be covered with thingauge metal or Army green tape. In someareas, negligible damage can be ignored.Use environmental protection for exter-nal repairs if possible. Where anaccess hole is large or can be madelarger for internal repair, an internalor external repair may be used.External repairs should be alignedwithin 15° either side of the directionof air flow.

f. General Repair Requirements.Restore structural continuity byrestoring original structure or bybridging the damage. Original strengthshould be restored if possible. Weightand appearance are unimportant in battledamage repair. Structural stiffnessshould be sufficient to assure loads areproperly distributed and to avoidserious vibrations. Use shims to avoidjoggles. Avoid hand formed and fittedparts. Where a stringer/stiffener islight (1-1/2 X 1-1/2 X 0.060 inches orless) and the stringers on either sideof the damage or fracture are sound,apply a skin patch 2 gauges thicker overthe damaged area.

g. Special Repair Techniques. Onemethod to create a complex curve in anormally straight angle or T - Profilemember is to place appropriate cuts andstop drill holes to allow bends, asgiven in Figure 4-16. This field expe-dient procedure will allow former repairfrom stray stock.

4-16. SKIN-STIFFENER DAMAGE.

GENERAL INFORMATION: These repairs areapplicable to any skin-stiffener/stringer structure such as the fuselage,fairings, and many secondary structuresother than sandwich construction.

OPTION 1: Patch Plate and SubstituteStiffener/Stringer.

LIMITATIONS: None - Condition 1. Inspectafter every flight for damage growth.

PERSONNEL/TIME REQUIRED: 2 Soldiers 2 Hours

MATERIALS/TOOLS REQUIRED: Substitute Stiffener or StringerSection

Skin Patch Cherry Rivets (item 37, Appx C)

PROCEDURAL STEPS:

1. Remove sections of the aircraft skinand stiffener/stringer containing thedamage. Smooth and round the cutout.Cleanup ends of the stiffener/stringer.Stop drill any remaining cracks, Figure4-17.

2. Cut and fit a skin patch one gaugethicker allowing overlap for at leasttwo rows of rivets, Figure 4-18.

4-51

..


Figure 4-16. Typical Former Repair (Sheet 1 of 2)

4-52


Figure 4-16. Typical Former Repair (Sheet 2 of 2)

4-53


Figure 4-17. Cutout in Damaged Skin

3. Cut a piece of substitute stringeror stiffener to extend a minimum of sixfasteners beyond the damage on each end.Use an angle, channel, or z-angle extru-sion, if available, with a cross sectionand strength equal to or larger than theexisting stiffener/stringer. Sometimesa single substitute stringer or stif-fener can be extended to provide supportfor several damages. This is betterthan individual repairs, as it willstiffen the airframe.

4. Remove rivets in the existingstiffener/stringer and back drill rivetholes in the substitute stiffener/stringer to match existing holes.Attempt to interpitch new fastenerswithin the existing rivet patternif the area is inaccessible forback-drilling.

5. Rivet the substitute stiffener/stringer in place, Figure 4-18, usingthe same size or larger rivets as thoseremoved.

NOTE

Stiffener can be placed on out-side; however, this configurationis nonpreferred.

7. Record BDAR action taken. Whenmission is complete, as soon aspractical, repair the equipment/systemusing standard maintenance procedures.

OPTION 2: Tape Repair.

LIMITATIONS: Repair may only beused on secondary structuremoisture out. No damage tostiffener/stringer allowed.

PERSONNEL/TIME REQUIRED: 1 Soldier 30 Minutes

MATERIALS/TOOLS REQUIRED: Army Green Tape (item 50,

or Aluminum Tape

to keep

AppX C)

6. Rivet patch plate over hole usingsame size as existing rivets.

4-54


Figure 4-18. Patch Plate

PROCEDURAL STEPS:

1. Smooth off ragged edges ondamaged skin.

2. Tape over hole. Use severallayers as necessary, and overlaponto skin well beyond damaged area.


4-17. CAP, SKIN, WEB, DOUBLERDAMAGE.

GENERAL INFORMATION: Much of thefuselage construction is relativelylight built-up structure. Smalldamage will likely exceed theallowable limits and will requirerepair. A patch plate can often beused to repair the damage.

LIMITATIONS: None - Condition 1.Inspect after every flight fordamage growth.


MATERIALS/TOOLS REQUIRED: Patch Plate Cherry Rivets (item 38, Appx C)

PROCEDURAL STEPS:

1. Remove sections of the aircraftcontaining the damage. Smooth andround the cutouts. Stop-drill anyremaining cracks, Figure 4-19.

2. Cut and fit a patch plate onegauge thicker and of the same materialas the damaged structure. The platethickness should be based on the thick-est part of the damaged area. The patchplate should be large enough to allowinstallation of the required fastenerson all sides. Cut and fit shims to fillgaps.

4-55


Figure 4-19. Typical Patch Plate Repair

4-56


3. Install a minimum of six rivets ineach row on each damaged end of majorstructure such as caps, extrusions, etc.Remove existing rivets and back drillholes in the patch plate if the area isaccessible. If back drilling is notpractical, it may be possible tointerpitch new rivets between existingrivets. Use same size rivets oroversize rivets if necessary.

4. Install two rows of rivets aroundpatch plate in webs and skins usingsame size as adjacent rivets in websand skin.


4-18. CAP OR LONGERON DAMAGE.

GENERAL INFORMATION: Nondeferrable capor longeron damage may be substantial,combined with skin damage. It willgenerally be necessary to repair the capor longeron first and then the skin. Itmay not be necessary to repair the skinfor structural reasons, but generallyskin repair is recommended to make awatertight repair.

LIMITATIONS: None - Condition 1. Inspectafter every flight for damage growth.


MATERIALS/TOOLS REQUIRED: Longeron or Cap - Sections used inoutside repairs should be angular orchannel shaped. The strength of thenew cap or longeron should be at leastthat of the damaged cap or longeron.Refer to Table 4-8 for substitutematerials to use on repair if alongeron or cap section is notavailable.

Skin Patch Blind Rivets (item 41, Appx C)

PROCEDURAL STEPS:

1. Remove sections of the aircraft skincontaining the damage. Do not cut capor longeron, but cut off ragged ends,Figure 4-20.

2. Make a patch plate. Plate should beas strong or stronger than originalskin. Overlap the hole for at least 2rows of rivets.

3. Cut a piece of substitute cap orlongeron to extend at least six faste-ners on all rows fore and aft of damagedsection. Sometimes a single substitutecap or longeron can be extended to pro-vide support for several damages. Thisis better than individual repairs, as itwill stiffen the airframe.

4. In the areas where the substitutecap or longeron will overlap on thedamaged cap or longeron sections, remove rivets which attach the damaged cap orlongeron to skin. Back drill rivetholes on the substitute cap or longeronto match existing holes on the damagecap or longeron.

5. Rivet the substitute cap or longeronin place using the same size or largerrivets as those removed in step 4.

6. Rivet patch plate over hole usingblind rivets. Use same size rivets asexisting rivets.

NOTE

Stiffener can be placed on out-side; however, this configurationis nonpreferred.


4-57


Figure 4-20. Expedient Cap/Longeron Repair

4-58


4-19. FRAME, BULKHEAD, SKIN, ANDSTRINGER DAMAGE.

GENERAL INFORMATION: A damaged flangeon a bulkhead or frame could be repaired fromthe outside in the same way as is a cap orlongeron. However, it is not desirable to have asection on the outside of the aircraft sticking outnormal to the airstream. Frame flanges aretherefore repaired by applying a strap over thedamage. If the damage to a highly loadedbulkhead is severe, then treat it like a cap and letthe section stick out in the airstream.

OPTION 1: Patch Plate Repair for SmallDamage.

LIMITATIONS: None – Condition 1.Inspect after every flight.


MATERIALS/TOOLS REQUIRED:Repair StrapCherry Rivets (item 41, Appx C)Tape or Skin Patch

PROCEDURAL STEPS:

1. Stop drill all cracks, Figure 4-21.

2. Cover the damage with tape. Be sure tocover the ends of all cracks.

3. Fabricate a repair strap using thick sheetmetal. The sheet metal should be 2 X thicknessof the original flange material, skin, and stringer.The strap should be wide enough to coverdamaged area and to allow at least two rows ofrivets on the skin, and a minimum of six rivets inthe undamage portion of damaged stringers. Thestrap should be long enough to overlap bothends of the damaged bulkhead or frame flangeby six rivets on each end. In the areas where

the repair strap will overlap on the damagedbulkhead flange and stringer, remove rivets andback drill if the area is accessible. If back drillingis not feasible, interpitch new rivets betweenexisting rivets.

4. Rivet the repair strap to the bulkhead orframe flange and stringer using the same size orlarger rivets. Rivet the strap to the skin using tworows of rivets around the perimeter using thesame size rivets as in adjacent skin-flangestructure.

5. Record BDAR action taken. When mission iscomplete, as soon as practical, repair theequipment/system using standard maintenanceprocedures.

OPTION 2: Combination Repair for MajorFrame or Bulkhead Damage.

LIMITATIONS: None — Condition 1.Inspect after every flight.


MATERIALS/TOOLS REQUIRED: Filler Patch Repair Doubler Skin Patch Cherry Rivets (item 41, Appx C)

PROCEDURAL STEPS:

1. Remove sections of the skin and frame orbulkhead containing the damage. Smooth andround the cutouts, Figure 4-22.

2. Cut and fit repair doubler for frame orbulkhead. Cut skin patch allowing overlap for atleast two rows of rivets. Repair patch anddoubler should be the same material and onegauge thicker than original material.

4-59


Figure 4-21. Repair of Damaged Bulkhead Flange

4-60


Figure 4-22. Typical Combination Repair (Sheet 1 of 2)

4-61


Figure 4-22. Typical Combination Repair (Sheet 2 of 2)

4-62


3. Remove existing rivets where therepair parts will overlap existingrivets if the area is accessible forback-drilling holes. If not, installrivets between existing rivets if spacepermits.

4. Rivet the repair parts in placeusing original diameter rivets or largerif necessary.


4-20. HONEYCOMB CORE FLOOR OR PANELDAMAGE.

GENERAL INFORMATION:

a. Part of the bottom shell, topdeck, shelves, interior panels, and thefin panels are honeycomb core struc-tures.

b. Various repair options are givenfor a range of damage size.

OPTION 1: Small Damage to One Skin andCore or Both Skins and Core - Less Than2 Inches Maximum Diameter.

LIMITATIONS: Procedure is designed onlyto keep moisture out. No additionalstrength has been added.

PERSONNEL/TIME REQUIRED:. 1 Soldier. 15 Minutes

MATERIALS/TOOLS REQUIRED:. Army Green Tape (item 47, Appx C)

or Aluminized Tape

PROCEDURAL STEPS:

1. Remove ragged edges, Figure 4-23.

2. Apply tape over repair to keep outmoisture.


OPTION 2: 2 to 8 Inch Damage, One Skinand Core.

LIMITATIONS: None.

PERSONNEL/TIME REQUIRED:. 1 Soldier● 90 Minutes

MATERIALS/TOOLS REQUIRED:● Metal Set or Equivalent Filler

Compound (item 2, Appx C)● Patch Plate● Cherry Rivets (item 38, Appx C). Solvent Cleaner; Naptha (item 5,

Appx C) or Equivalent

PROCEDURAL STEPS:

1. Remove damaged skin and core, Figure4-24. Clean surface 6 inches aroundholes with cleaner. The maximum damagedarea that may be cut out is 8 inches.

2. Make a patch plate as shown in Figure4-25. Make plate 2 inches larger thancutout. Lay out and drill rivet pattern.

3. Completely fill void with metal setfill compound. Add slight excess toallow for shrinkage.

4. Apply metal set to area between thepatch plate and panel. Assemble topanel with 1/8 blind rivets.


OPTION 3: Damage to Both Skins andCore, 2-8 Inch, Only One Side of Panelis Accessible.

LIMITATIONS: None.

4-63


2“ MAX

Figure 4-23. Damaged Honeycomb Core Panel,Small Damage to One Skin and Core

Figure 4-24. Damaged Honeycomb Core Panel,2-8 Inch Damage - One Skin and Core

MAKE PATCH FROM 2024-T3OR 7075-T6 ALCLAD ALUMINUM

1/8” CHERRY RIVET2 DIA EDGE DISTANCE4 DIA RIVET SPACINGTHRU ONE SKIN ONLY

PATCHREPAIR PATCHAND FASTENERSAND SEALANT

FILLER COMPOUND

Figure 4-25. Repaired Honeycomb Core Panel,2-8 Inch Damage - One Skin and Core

4-64


PERSONNEL/TIME REQUIRED:● 1 Soldier. 2 Hours

MATERIALS/TOOLS REQUIRED:. Drill with No. 30 Bit● Router● Metal Set (item 2, Appx C) or

Equivalent Filler Compound● 2 Patch Plates. Cherry Rivets (item 38, Appx C)● Rivet Gun● Solvent (item 47, Appx C)

PROCEDURAL STEPS:

1. Remove damaged skin and core using arouter to route all damage on outer andinner skins. Enlarge the hole on theouter skin and honeycomb so that a 1Inch rim surface of the inner skin isexposed, as shown in Figure 4-26.

2. Make two patch plates. One patchplate is for inner skin; the other forthe outer skin, Figure 4-27.

3. Apply sealant to exposed surface ofinner skin. Assemble patch plate to theinner skin with cherry rivets.

4. Completely fill void with metal setfill compound. Add slight excess toallow for shrinkage.

5. Let harden. Sand smooth. Applysealant to the area between the outerpatch and skin. Assemble patch to outerskin with 1/8 cherry rivets.


OPTION 4: Damage Over 8 Inches to BothSkins and Core.

LIMITATIONS: None.

PERSONNEL/TIME REQUIRED:● 1 Soldier● 2 Hours

MATERIALS/TOOLS REQUIRED:. 2 Patch Plates● Cherry Rivets

PROCEDURAL STEPS:

1. Remove damaged skin and core, Figure4-28. Clean top and bottom skins 6inches around holes with cleaner. Themaximum damaged area that may be cut outis 12 inches.

2. Make two patch plates, 0.04 inch orthicker, as shown in Figure 4-28. (Ifdamage is in an area where installing aninterior patch is not possible or wheresharp edges from rivets on an interiorpatch might cause damage, a singleexterior patch plate, 0.05 inch thick,may be used.) Make plates 2 incheslarger than the cutout. Lay out anddrill a rivet pattern, two rows, asshown.

3. Assemble with 2 rows of cherry rivets.


OPTION 5: Secondary Structure Repair.

LIMITATIONS: This option is recommendedfor secondary structural areas, whichhave a honeycomb core between the walls,where repair is required for aerodynamicreasons or to keep water out of aircraft.

PERSONNEL/TIME REQUIRED:● 1 Soldier

. 1 Hour

MATERIAL/TOOLS REQUIRED:● Patch Plate, 0.020 Inch (Minimum)

Aluminum or Steel● Cherry Rivets (item 38, Appx C)● Sealant (item 5, Appx C). Rivet Gun● Solvent (item 7, Appx C). Drill and Bit

4-65


Figure 4-26. Damage Repair, Accessible One Side Only

Figure 4-27. Patch Plates, One Side Accessible Repair

4-66


Figure 4-28.Damage Over

Repair of Honeycomb Core Panel,8 Inches - Both Skins and Core

4-67


PROCEDURAL STEPS:

1. Remove protruding sections ofdamaged skins and core. Clean area withsolvent.

2. Cut patch plate to fit over hole,allowing 1 inch overlap on all sides.

3. Lay out and drill rivet pattern onoverlapping area.

4. Apply sealant to underside of patchplate on overlapping area.

5. Assemble patch plate to panel withrivets.


4-21. WINDOW SHIELD/WINDOW DAMAGE.

GENERAL INFORMATION: In general,repairs to transparencies are at bestmake-shift and usually result in seriousimpairment of clear vision charac-teristics. Damaged sections should bereplaced as soon as possible.

LIMITATIONS: Restricted vision.Inspect after every flight for damagegrowth.

PERSONNEL/TIME REQUIRED:● 1 Soldier● 1 Hour

MATERIALS/TOOLS REQUIRED:. Safety Wire (item 25, Appx C)● Sealant (item 4, Appx C). Tape (item 50, Appx C)

PROCEDURAL STEPS:

1. Stop drill a hole at the end of eachcrack, Figure 4-29. If tolerable, cutout a hole to include the ends of allcracks. This will restrict visionfurther. Smooth ragged edges.

2. Drill small holes 1/2 to 3/4 inchspacing, 3/8 inch edge distance alongboth sides of any crack and along thesides of the hole.

3. Lace safety-wire with needle nosepliers through holes and across cracksand over hole, forming a web with 1/2 to3/4 inch spacing between wires. Pullwires tight.

4. Brush epoxy sealant over safety wireand crack to make a water tight seal.

NOTE

Holes too large to be closed withsafety-wire and epoxy may be sealedtemporarily with Army green tape.


4-22. TAIL BOOM SKIN DAMAGE.

GENERAL INFORMATION: The tail boom is abasic monocoque structure with no longi-tudinal skin stiffeners or longerons.The tail boom is unserviceable if damageis extensive enough to cause misalign-ment. Damage which does not exceed 10percent of tail boom circumference inheight and 30 percent of tail boom cir-cumference in length may be repaired bypatching. (Circumference to measuredat aft end of damage.) A maximum of TWOdamaged areas per stress section of thetail boom is permitted. Example, a linedrawn around the circumference of thetail boom must not touch more than TWOdamaged areas. Damaged areas must be aminimum of 8 inches apart. Total damageto tail boom is not to exceed 5 percentof the tail boom area (approx. 160square inches).

4-68


Figure 4-29. Fracture Lacing With Safety Wire

4-69


LIMITATIONS: None - Condition 1.Inspect after every flight fordamage growth.

PERSONNEL/TIME REQUIRED:● 1 Soldier. 2 Hours

MATERIALS/TOOLS REQUIRED:● Skin Patch● Cherry Rivets (item 37, Appx C)● EA93NA Adhesive (item 6, Appx C)

PROCEDURAL STEPS:

1. Remove sections of the tail boomskin containing the damage. Stopdrill remaining cracks. Clean updamaged skin using a minimum 0.125inch radius.

2. Prepare a patch of 2024-T3 aluminum0.050 thick and shape to contour of tailboom. The patch must extend a minimum of3 inches forward and aft, and 1 inch aboveand below the damaged area, Figure 4-30.

3. Sand surfaces lightly to remove allsurface finish. Clean areas with cleaner.Bond patch to surface with EA934NAadhesive.

4. Install a minimum of three rows ofrivets running circumferentially on eachend and a minimum of one row of rivetstop and bottom running longitudinally inthe patch. Rivet size to be the same asskin lap joints, Figure 4-30.


Figure 4-30. Tail Boom Skin Damage

4-70

TM 55-1520-228-BD

CHAPTER 5

ALIGHTING GEAR





5-1. SCOPE. This chapter containsinformation for deferring repair andexpedient field fixes of battle damagedalighting gear assembly. The repairs orfield fixes can only be applied to theskid tubes.

5-2. DESCRIPTION. The alighting gearassembly, Figure 5-1, consists of twotubes (1) and two arched crosstubes (2)and (3) fastened together with skidsaddles (4), and attaching hardware.The assembly is attached to the lowerstructure with support assemblies(5 and 6) at four points.

Replaceable steel skid shoes (7) areattached to the bottom of the skidtubes to prevent damage from contactwith the ground.


5-4. REPAIR PROCEDURE INDEX.

PARA.

Hard Landings, Sudden Stops . 5-6Skid Damage . . . . . . . . . 5-7

Section II. SKID TUBE

5-5 ● GENERAL INFORMATION.

a. In battle conditions, part of theskid tube may sustain various amounts ofdamage which may be deferred.

NOTE

The conditions in this paragraphapply only to damage to the skidtube (1, Figure 5-l).

b. Deferrable skid tube damage:

(1) Damage to Sections A and E,Figure 5-2, may include up to completerupture.

(2) Damage to the junction of thecrosstubes and skid tube, Sections B andD, Figure 5-2, may include up to one-half of the cross section of the skidtube as long as alighting gear is nottoo badly deformed.

(3) Damage to Section C, Figure5-2, may be deferred unless skid tube isso deformed that alighting gear is notfunctional.

5-6. HARD LANDINGS, SUDDEN STOPS.

GENERAL INFORMATION.

a. Any hard landings which per-manently deform the crosstubes, so thatthe spread of the skid tubes is inexcess of 74 inches, may cause damage tothe structure, transmission, or rotor.

b. Binding or unusual noises in thetransmission may require replacement ofrotor and the transmission. This is notBDAR.

NOTE

Aircraft grounded until assessedflight worthy.

5-1

TM 55-1520-228-BDALIGHTING GEAR

Figure 5-1. Landing Gear and Support Installation

Figure 5-2. Skid Tube Damage Zones

5-2


Table 5-1. Assessment Procedure Logic

5-3


c. Visually inspect structures sup-porting alighting gear attachment pointsand transmission attachment points forany signs of structural distress such asbuckling, cracks, rupture, deformation,popped rivets, or elongated rivet holes.If no such damage is found, replacementof alighting gear may be deferred if itis still functional, and aircraft may bereleased for fully mission capableflight. Watch for any unusual vibra-tions in flight. Inspect after everyflight until alighting gear can bereplaced.

d. If alighting gear supportingstructure is damaged but still func-tional and the transmission supportingstructure shows no damage, release forflight. Watch for any unusual vibra-tions in flight. Inspect after everyflight until structure and alightinggear can be replaced.

e. If alighting gear or its sup-porting structure is not functional orthe transmission or its supportingstructure show any sign of damage,aircraft will be grounded until problemis corrected. This will most likely gobeyond scope of BDAR.

Section III. SKID DAMAGE

5-7. SKID DAMAGE.

GENERAL INFORMATION: Landing skids maybe damaged by wear or enemy fire. Iftime is available, repair can be per-formed to prevent further damage tolanding skids.

LIMITATIONS: Use care in landing.PERSONNEL/TIME REQUIRED:● 2 Soldiers. 2 Hours

MATERIALS/TOOLS REQUIRED:. 0.032 In. Sheet Metal. Blind Fasteners (item 36, Appx C)● Drill Bit and Motor

PROCEDURAL STEPS:

1. Form plate to fit snug around skid.Drill oversize holes along each edge tomatch attachment holes in skid tube.

Plate should extend one foot on eachside of damaged area. Locate center ofplate at center of skid tube, Figure5-3. If there are no impediments, thenew plate may be installed over the oldshoes; otherwise remove shoes. Installplate using 1/4 inch cherry rivets orsteel clamps, Figure 5-4. Clamps may befabricated if not available, Figure 5-5.

NOTE

The aft end of the skid tube isbent up, and a steel plate cannotbe formed to follow this contour.Do not extend steel plate beyondstart of curvature.


5-4


Figure 5-3. Skid Repair

Figure 5-4. Clamp Repair

5-5


Figure 5-5. Fabricated Clamp

5-6

TM 55-1520-228-BD

CHAPTER 6

POWER PLANT




Section I.

6-1. DESCRIPTION, POWER PLANT. Thepower plant consists of a T63-A-700 onthe OH-58A and a T63-A-720 on the OH-58Cmounted between FS120.O and FS206.0,Figure 6-1. Engine connections areprovided for fuel, oil, electrical,instrument, and engine control systems.Major sections of the engine are theair-inlet, compressor, combuster, tur-bine, and power and accessory gearbox.All BDAR repairs discussed in thischapter are applicable to both enginemodels.

6-2. ASSESSMENT PROCEDURES. Combatdamage to the engine usually requiresengine replacement. The logic diagram,

6-4. GENERAL.expedient fixes

INTRODUCTION

Table 6-1, refers to BDAR repair proce-dures which have been developed.


PARA.

Air Bleed Valve Inoperative 6-5Double-Check Valve

Inoperative . . . . . . . . 6-6Oil Tank Punctured. . . . . . 6-7Oil Lines (Rigid) Type

Repair. . . . . . . . . . . 9-7Fuel, Oil, Pneumatic

Line Repair . . .

Section II. COMPONENT EXPEDIENT FIXES

This section has variouswhich can restore the

helicopter’s mobility in the event ofengine failure. Engine malfunctionscan be detected from the followingobservations:

a. Abnormal oil pressure, temperaturereadings, or warning lights.

b. Abnormal noises or high frequencyvibrations.

c. Sudden loss of power.

6-5. AIR BLEED VALVE

GENERAL INFORMATION:

. . . . . 9-8

INOPERATIVE.

During enginestart-up (or part-speed operation), thecompressor is susceptible to surge dueto high pressure build-up in the rearstages. An air bleed valve is employedto discharge the high-pressure air inorder to alleviate the stall condition.The bleed valve is initially in the openposition and senses pressures betweenthe fifth stage and the scroll. Oncethe stall region is overcome (usuallybetween 65 percent to 75 percent N1) andscroll pressure is reached, the valve isclosed. Should the valve not closecorrectly, excess air will be dumped atthe compressor and the required burnerpressure will not be obtained resultingin engine abort.

6-1

TM 55-1520-228-BDPOWER PLANT

Figure 6-1. T63 Series Engine

6-2

POWER PLANT

Table 6-1. Engine BDAR Assessment Logic

6-3


LIMITATIONS: Revised engine startprocedure.

Blocking of the air bleed valvewill render the engine highlysusceptible to surge which couldresult in catastrophic damageto the engine.

PERSONNEL/TIME REQUIRED: 1 Soldier. 30 Minutes

MATERIALS/TOOLS REQUIRED: Sheet Metal, 2 X 3 In.,

Thickness 0.032 Sheet Metal Snips

PROCEDURAL STEPS:

Manufacture a blocking plate, Figure6-2.

2. Loosen three bolts which securebleed valve to compressor manifold.

3. Slide blocking plate between bleedvalve and mounting flange.

4. Retighten three bolts which securebleed valve to compressor manifold.

Blocking of air bleed valve couldresult in catastrophic damage tothe engine. The following revi-sions must be incorporated.

5. Complete normal engine start proce-dure except for the following:

NOTE

a. When increasing fuel to theengine, grasp the throttle firmly withboth hands and accelerate engine slowly.

b. Monitor TOT and N1 gauges forpossible stall readings.

NOTE

Stall usually occurs between 65percent and 75 percent N1.

c. If stall is present, TOT will riserapidly and N1 RPMs will fluctuatebetween 65 percent and 75 percent.

If gauges indicate a stall is pre-sent, do not overreact. A quickshutdown of engine will decrease N1RPMs reducing pressure at the inletcausing the fire to come forwardthrough the engine.

d. If gauges indicate stall, hold thethrottle firmly. If N1 does not pickupRPM, slowly decrease throttle fuel demand.

If stall condition is overcome,engine must now be run in fullpower operation.

6. If engine start is achieved, N1 mustbe maintained above 80 percent. Reduc-tion to part-speed operation could in-troduce possible stall implicationsresulting in engine flameout withoutauto-relight capability.


Bring engine up to 60 percent N1and hold for a minimum of two min-utes. A gradual acceleration isrequired to avoid a stall condition.

6-4

1.


Figure 6-2. Blocking Plate Installation

6-6. DOUBLE-CHECK VALVE INOPERATIVE.

GENERAL INFORMATION: The double-checkvalve, along with both accumulators, issituated in-line between the power tur-bine governor and the fuel control, andacts as a dampener for surge control.This system feeds into the fuel controlto insure a steady stream of secondaryfuel should the compressor flow becomeinconsistent. It also decelerates aquick reaction from pilot input. Withthese factors in mind, the pilot must bemade aware that if any component of thesystem is removed or bypassed, any inputwill result in erratic engine response.At all times, the integrity of all fuelcontrol lines must be maintained. Nolines may be deleted or plugged.

NOTE

Should any of the three componentssustain damage or otherwise berendered inoperable, the remainingfunctional items should be recon-nected. In emergency situations,when time is of the essence, thecomplete system may be bypassed(option 2). This option resultsin the most unstable condition forthe pilot and is therefore leastdesirable.

OPTION 1: Remove Defective Component.

LIMITATIONS: Erratic engine response.


6-5


MATERIALS/TOOLS REQUIRED:. Flex Line Tubing (ID 0.25 in.,

Length 12 in. min). No. 4 Fittings

PROCEDURAL STEPS:

1. All connections and fittingsthroughout the system incorporate thesame thread pattern and therefore avariety of configurations may beachieved. Should the system be inoper-able, remove only the defective compo-nent(s) and reconstruct the system.Refer to Figure 6-3 to determinepossible alternatives.

2. Reuse existing o-rings whenpossible. If o-rings are severelydamaged, scavenge off removed component.

CAUTION

All fuel control lines must bemaintained. No lines may bedeleted or plugged.

3. Insure the lines between the fuelcontrol and the governor are intact andnot leaking.

4. If any leakage is incurred due tothe above procedure and cannot becorrected or if time constraints takeprecedent, the system may be bypassed asa last resort, refer to option 2.


MATERIALS/TOOLS REQUIRED:. Flex Line Tubing (ID 0.25 in.,

Length 12 in. rein). No. 4 Fittings

1. Refer to Figure 6-3(b) to establishbypass configuration.

2. Disconnect clamp from flexible hoseand extend flexible hose to rigid hose.

3. Use fitting from either hose andconnect the two hoses.

4. Insure both o-rings are reusable andno leakage exists. If either o-ring isdamaged, scavenge from bypassed compo-nents.

6-7. OIL TANK PUNCTURED.

GENERAL INFORMATION: The engine willseize in a matter of minutes if runwithout oil. This procedure lists sixmethods to fix a leaking oil tank,depending on the size of the leak andthe materials available. If fuel cellrepair kit is available, utilize itscontents.

LIMITATIONS: None.

NOTEOPTION 2: Bypass Entire System.

LIMITATIONS: Erratic flight control.

NOTE

The pilot must be made aware thatany fuel demand he places on theengine will be reacted upon imme-diately leading to quick engineresponse and erratic flightcontrol.

Some repairs may come loose dueto heat and vibration.

OPTION 1: Wood Plug (for Smooth RoundHoles).


MATERIALS/TOOLS REQUIRED:. Plug, Wooden. Hose or Tubing

6-6


Figure 6-3. Double-Check Valve System, Possible Alternatives

6-7


PROCEDURAL STEPS:

1. Obtain a small piece of hose ortubing and insert the piece into thehole on the oil tank, Figure 6-4.

2. Insert a tapered wooden plug insidethe hose or tubing (wooden plug shouldbeif

3.

4.

checked periodically and retightenednecessary).

Replenish oil supply.

Record BDAR action taken. Whenmission is complete, as soon aspractical, repair the equipment/systemusing standard maintenance procedures.

Figure 6-4. Wood Plug

OPTION 2: Duct Tape (for thin cracks).


MATERIALS/TOOLS REQUIRED:. Tape, Fiberglass or Duct

(item 51, Appx C). Solvent, Naptha (item 7, Appx C)

or Equivalent

PROCEDURAL STEPS:

1. Clean area around crack with solventto remove the oil.

2. Seal crack with tape.

3. Replenish oil supply.


OPTION 3: Sealant (for small holes)

PERSONNEL/TIME REQUIRED:. 1 Soldier. 1 Hour

MATERIALS/TOOLS REQUIRED:. Solvent, Naptha (item 7, Appx C)

or Equivalent. Sealant, Silicon (item 4, Appx C)

or Equivalent. Wood Plug

PROCEDURAL STEPS:

1. Clean area around hole with solventto remove all traces of oil so sealantwill stick.

2. Fill hole and surrounding area withsealant.

3. If hole is large enough, use woodplug as a filler while filling hole withsealant, Figure 6-5.

4. After sealant has dried, replenishoil supply.


6-8


4. Replenish oil supply.

5. Record BDAR action taken. Whenmission is complete, as soon aspractical, repair the equipment/system

Figure 6-5. Sealant for Small Holes

OPTION 4: Screw, Washer, and Gasket(for small holes)


MATERIALS/TOOLS REQUIRED:. Screw, Sheet Metal. Gasket Material (item 20, Appx C). Washer

PROCEDURAL STEPS:

1. Cut a piece of gasket material thatwill overlap the hole by about 1 inchfrom the center of the hole.

2. Pierce a small hole in the center ofthe gasket material.

3. Using the sheet metal screw andwasher, screw the gasket materialthrough the pierced hole and through thesmall hole on the oil tank onto the oiltank wall to stop the leak, Figure 6-6.

using standard maintenance procedures

Figure 6-6. Repair Using Screw,Washer and Gasket

OPTION 5: Hose Assembly, Sealant, Nutand Bolt.

PERSONNEL/TIME REQUIRED:. 1 Soldier. 2 Hours

MATERIALS/TOOLS REQUIRED:. Nut, Bolt, and Washer. Sealant, Silicon (item 4, Appx C)

or Equivalent. Hose or Tubing. Solvent, Naptha (item 7, Appx C)

or Equivalent

PROCEDURAL STEPS:

1. Clean area around hole with solventto remove all traces of oil so sealantwill stick.

6 - 9


2. Use a piece of hose/tubing about thesame diameter of the hole. Assemblebolt, hose/tubing, washer, and nut,Figure 6-7. Apply sealant to alledges. Start nut on bolt and tubinguntil assembly is snug.

3. File edge of hole until round andsmooth. Push hose assembly about half-way through hole. Tighten-nut on boltexpand hose to seal hole. If necessary,remove oil tank plate to allow a wrenchor pliers inside of oil tank to holdnut while turning bolt.

4. If oil tank plate was removed,reinstall.



Figure 6-7. Hose Assembly, Sealant, Nut, and Bolt

6-10


OPTION 6: Sheet Metal with Sealantand/or Blind Rivets (for large holes).

PERSONNEL/TIME REQUIRED:. 2 Soldiers. 3 Hours

MATERIALS/TOOLS REQUIRED:. Sheet Metal. Sealant, Silicon (item 4, Appx C)

or Equivalent. Blind Rivets or Sheet Metal Screws

(item 39, Appx C). Solvent, Naptha (item 7, Appx C)

or Equivalent. Gasket Material (item 20, Appx C)

PROCEDURAL STEPS:

2. If sealant is to be used, clean areaaround hole with solvent so sealant willstick.

3. Put sealant or gasket material overhole. Put sheet metal plate over holeand secure with sheet metal screws orblind rivets.



1. Cut a piece of sheet metal that willoverlap the hole by 1-1/2 inches at allpoints, Figure 6-8.

6-11


I

Figure 6-8. Sheet Metal Plate with Sealant and/or Cherry Rivets

6-12

TM 55-1520-228-BD

CHAPTER 7

ROTORS




Section 1. INTRODUCTION

7-1. SCOPE. This chapter contains the 7-3. ASSESSMENT PROCEDURES. Refer tofault assessment and expedient repair Table 7-1.procedures available to find and fixbattlefield damage to the main and tail 7-4. REPAIR PROCEDURE INDEX.rotor blades.

PARA.7-2. GENERAL. The system consisting oftwo blade assemblies, each with two Rotor Blade, Hole 1 Inchblades, a central hub, and a control Diameter or Less. . . . . . 7-6mechanism. The main rotor is driven by Main Rotor Blade, Hole 1 to 4the mast which is connected to the Inches Diameter Maximum . . 7-7transmission and provides for fore, aft,lateral, and vertical flight modes. Thetail rotor is driven by the tail rotorgearbox and provides for directionalcontrol. See Figures 7-1 and 7-2 forsystem configuration. Assessment proce-dures are found in Table 7-1.

Section II. REPAIRS

7-5. GENERAL. The rotor system doesnot lend itself well to limited repairs.In most instances, the only repairoptions for a faulty component will beto replace or repair by normal proce-dures. Those limited repairs whichhave been developed are listed in thissection.

7-6. ROTOR BLADE, HOLE 1 INCHDIAMETER OR LESS.

GENERAL INFORMATION: A small holepassing through the honeycomb core area,Figure 7-3, on either a main or tailrotor blade can be repaired with duct

LIMITATIONS: Adjustment of bladebalance may be required after repair.Inspection of repaired area after eachflight would be required.

PERSONNEL/TIME REQUIRED:. 2 Soldiers. 15 Minutes

MATERIALS/TOOLS REQUIRED:. Army Green 3 Inch Tape or Aluminized

Tape (item 50, Appx C). Cleaning Solvent (item 7, Appx C)

PROCEDURAL STEPS:

tape. Removal of blade is not necessary. 1. Position blades for access todamaged area. Support blades to preventmovement and droop.

7-1

TM 55-1520-228-BDROTORS

1. Pitch Link 10. Blade Latch2. Lever 11. Blade Assy3. Idler Link 12. Retaining Bolt4. Swashplate Assy 13. Grip5. Link 14. Mast Nut6. Collective Lever 15. Hub Assy (Oil Lubricated shown)7. Inner Ring 16. Pitch Horn8. Outer Ring 17. Mast9. Collar

7-2

Figure 7-1. Main Rotor System

1. Hub2. Pitch Horn3. Blade4. Tail Rotor Gearbox


Figure 7-2. Tail Rotor System

7-3


Table 7-1. Assessment Procedures

7-4


Figure 7-3. Rotor Blades, Damage Sensitive Areas

7-5


2. Smooth damage; remove all roughedges.

3. Clean area around damage andcompletely around blade where tape isto be applied.

4. Cover hole with a chordwise layerof tape, top and bottom of blade.Extend ends of tape 2 inches beyondarea of damage, Figure 7-4.

5. Wrap a second layer of tape chord-wise over the first layer and aroundthe entire blade. Overlap ends by 3inches with outside edge of top towardtrailing edge.

6. Wrap exact number of tape wraps onopposite sispan locati

7. Recordmission ispractical,using stand

de at approximately sameon.

BDAR action taken. Whencomplete, as soon asrepair the equipment/systemard maintenance procedures.

7-7. MAIN ROTOR BLADE, HOLE 1 T0 4INCHES DIAMETER MAXIMUM.

GENERAL INFORMATION: A medium sizehole in the honeycomb core area, Figure7-3, of a main rotor blade can be tem-porarily repaired by fashioning a patchusing aluminum foil as a pluggingmaterial. Removal of blade is notnecessary. This repair is limited tocertain areas of the blade as shown inFigure 7-5.

LIMITATIONS: Adjustment of bladebalance may be required after repair.Inspection of repaired area after eachflight would be required.

PERSONNEL/TIME REQUIRED:. 2 Soldiers. 1 Hour

MATERIALS/TOOLS REQUIRED:. Army Green Tape, Maximum Width

Available; 3 Inches Minimum orAluminized Tape (item 50, Appx C)

. Fiberglass or Aluminum Wafers

. Aluminum Foil or Other FillerMaterial (item 18, Appx C)

. Adhesive Package

PROCEDURAL STEPS:

1. Position blades for access to damagearea. Support blades to prevent movementand droop.

2. Smooth damage; remove all rough edges.

3. Clean area around damage and com-pletely around blade where tape is tobe applied.

4. Make a plug of crushed aluminum foilor other filler material shaped to fitin the hole. Do not make the plug toodense; voids should be about 1/4 inch.Apply spots of adhesive to the aluminumsheet before crushing so plug will havesome strength. Apply adhesive sparselyto the finished plug in the area whereit will come in contact with the bladesandwich material.

5. Insert plug in hole. Hole shouldbe well packed,

6. Cut out a fiberglass or aluminumwafer so it just fits over the holewithout overlapping the external bladeskin. Apply adhesive to the bottom ofthe wafer where it comes in contact withthe aluminum plug, and close the hole.

7. Cover hole with Army green tape.Tape should extend 2 inches beyond edgeof the hole, Figure 7-4.

7-6

TM 55-1520-228-BD

ROTORS

Figure 7-4.Rotor Blade Repair, Application of Tape

7-7


8. Wrap a layer of tape around the 10. Record BDAR action taken. Whenentire blade and over the repaired area. mission is complete, as soon as

practical, repair the equipment/system9. Wrap exact number of tape wraps on using standard maintenance procedures.opposite side at approximately same spanlocation.

Figure 7-5. Repair Areas - Main Rotor Blades

7-8

TM 55-1520-228-BD

CHAPTER 8

DRIVE TRAIN SYSTEM




Section I.

8-1. GENERAL. The drive train is asystem of shafts and gearboxes throughwhich the engine drives the main rotor,tail rotor, and such accessories asrotor tachometer generator and hydraulicpump. (See Figure 8-1 for drive trainsystem configuration.)

8-2. DRIVE TRAIN DAMAGE. The drivetrain system does not lend itself wellto limited repairs. In most instances,the only repair options for a faultycomponent will be to replace or repairby normal procedures. Those limitedrepairs which have been developed arelisted in this section.

INTRODUCTION


8-4. REPAIR PROCEDURES INDEX.

PARA .

Drive Train Damage. . . . . . 8-2Drive Train Component Damage. 8-5Transmission Oil Cooling Air

Duct Repair . . . . . . . . 8-6Oil Pressure Transmitter Leak 8-7Low Pressure Sensing Switch . 8-8Oil Hoses and Lines, Leaks

or Restrictions . . . . . . 8-9Transmission Bullet Damage. . 8-10Tail Rotor Gearbox Bullet

Damage. . . . . . . . . . . 8-11

Section 11. REPAIR

8-5. SENSITIVITY OF DRIVE TRAIN SYSTEMTO BATTLEFIELD DAMAGE. The drive trainsystem includes a number of componentswhich, if damaged or deformed (bent) inany way or fail internally, will renderthe system inoperable or severelydegrade flight characteristics orsafety. The system is particularly sen-sitive to any damage which adverselyaffects any of the following:

a. Internal operation of transmission,freewheeling assembly, or tail rotorgearbox.

b. Operation of the transmission oilsystem.

c. Straightness, original shape, orintegrity of either the mast, drive-shafts, or output shaft at tail rotorgearbox.

8-6. AIR DUCT HOSE DAMAGE.

GENERAL INFORMATION: Holes, tears, ordistortions in air duct hose (16, Figure8-2) can result in less than therequired amount of cooling air reachingthe oil cooler (2, Figure 8-2). Thiscondition may cause the transmission oilsystem to operate at above normal tem-perature. Several repairs can beapplied depending on accessibility andthe nature and extent of damageincurred. Various repairs are shown atFigure 8-3.

8-1

2.3.4.5.

6.

8.9.

Mast 10. Disc AssyTransmission Assy 11. Bearing Hangar and SupportMain Driveshaft BracketFreewheeling Assy 12. Hangar (Blower Assy)Forward Short Tail Rotor 13. Oil Cooler

Driveshaft 14. Coupling (Main Driveshaft)Oil Cooling Blower and 15. Splined Adapter

Shaft Assy 16. Oil Filter AssyAft Short Tail Rotor Driveshaft 17. Tail Rotor DriveshaftLong Tail Rotor Driveshaft SegmentTail Rotor Gearbox Assy

SEE DETAIL A

(PRIOR TO COMPLIANCE WITH MWO 55-1520-228-50-25!

TM 55-1520-228-BD DRIVE TRAIN SYSTEM

8-2

Figure 8-1. Drive Train System (Sheet 1 of 4)

1.

7.

TM 55-1520-228-BD DRIVE TRAIN SYSTEM

8-3


TM 55-1520-228-BD

DRIVE TRAIN

SYSTEM

Figure 8-1.Drive Train System (Sheet 3 of 4)

8-4

TM 55-1520-228-BDDRIVE TRAIN SYSTEM


8-5


Table 8-1. Drive Train System BDAR Assessment Procedures

8-6


LIMITATIONS: None.


MATERIALS/TOOLS REQUIRED:. Pliers. Duct Tape (item 51, Appx C). Wire Cutters. Thin Pliable Material

PROCEDURAL STEPS: (Refer to Figure 8-3,Repairs A, B, C, D.)

1. Hole or tear in fabric. Wrapseveral turns around duct to cover holeor tear. Tape should extend beyonddamaged area 1 to 2 inches in eachdirection. Refer to repair A.

2. Distorted duct.

a. Using pliers and wire cutters,reshape or cut away the portion of ductwhich would create an air flow restric-tion or which is badly distorted. Note:If wire frame work below fabric is cutthrough, refer to step 3, severed duct.

b. If repair area is not at a bendportion of duct routing, a repair can beapplied as shown at either repair B orC. If repair area is located at a bendportion of duct routing, a repair can beapplied as shown at repair B.

c. Tape should extend beyond damagedarea 1 to 2 inches in either direction.

3. Severed duct.

a. Using pliers and wire cutters,reshape or cut away any portion of ductwhich would create an air flow restric-tion or which is badly distorted.

b. If area to be repaired is not in abend portion of duct routing, a repaircan be applied as shown at either repairB, C, or D. If area to be repaired isin a bend portion of duct routing, arepair can be applied as shown at eitherrepair B or D.

c. Tape should extend beyond damagedarea 1 to 2 inches in either direction.


8-7. OIL PRESSURE TRANSMITTERLEAK.

CAUTION

If 8-7 and 8-8 repairs areaccomplished, there will be noOil Pressure Monitoring System.

GENERAL INFORMATION: If oil is beinglost due to damage at oil pressuretransmitter (7, Figure 8-2), thetransmitter can be removed and replacedwith a threaded plug provided XMSN OILPRESS warning light is operable and con-sidered reliable.

LIMITATIONS: Early warning of high oilpressure conditions would be eliminatedsince the transmission oil gauge wouldbe rendered inoperable. XSMN OIL PRESSwarning light would give early warningbut for low pressure conditions only.


MATERIALS/TOOLS REQUIRED:. Pliers. Open End Wrench. Tie Wraps. Plug, MS24391D4L (same as 7, Figure

8-2 )

PROCEDURAL STEPS: (Refer to Figure 6-2.)

1. Cut lock wire at transmitter (7).

2. Remove electrical connector fromtransmitter (7).

3. Remove transmitter (7) and packing.Retain packing.

8-7


1.2.3.4.5.6.7.

8 .

Filler Cap 9. Oil FilterOil Cooler 10. Oil Filter Head AssyTransfer Tube 11. Filter Bypass ValveNozzle (Jet) 12. Oil Temperature SwitchPressure Regulating Valve 13. Oil PumpHoses and Lines 14. Chip DetectorOil Pressure Transmitter 15. Chip DetectorP l u g 16. Air Duct HosesLow Pressure Sensing Switch

Figure 8-2. External Components - Transmission Oil System

8-8


Figure 8-3. Flex Duct Repair (Sheet 1 of 2)

8-9


Figure 8-3. Flex Duct Repair (Sheet 2 of 2)

8-10

4. Install plug and packing wheretransmitter (7) was previouslyinstalled.

5. Secure loose electrical connectorand cable with tie wraps.

6. Check for leaks.


8-8. LOW PRESSURE SENSING SWITCHLEAK.

GENERAL INFORMATION: If oil is beinglost due to damage at low pressuresensing switch (8, Figure 8-2), theswitch can be removed and replaced witha threaded plug, provided thetransmission oil pressure gauge isoperable and reliable.

LIMITATIONS: XMSN OIL PRESS warninglight would be inoperable. Only thetransmission oil pressure gauge wouldmonitor transmission oil pressure.


MATERIALS/TOOLS REQUIRED:. Pliers. Tie Wraps. Open End Wrench. Plug, MS 24391D4L (same as 7, Figure

8-2 )


4. Install plug and packing whereswitch (8) was previously installed.

5. Secure loose electrical connectorand cable with tie wraps.

6. Check for leaks.


8-9. OIL HOSES AND LINES, LEAK ORRESTRICTION (CRIMP).

GENERAL INFORMATION: Damaged oil hosesand lines (6, Figure 8-2) of thetransmission oil system may be repairedby manufacturing a new hose or line orby installing a replacement section forthe damaged section. Similar repairsare outlined at Chapter 9, Section II,and may be utilized for the transmissionoil system.

8-10. TRANSMISSION-BULLET DAMAGE.

GENERAL INFORMATION: If the trans-mission is hit by a bullet which exitson the opposite side, the transmissiondoes not bind and there is no oil loss,repair may be deferred. Aircraft isfully flight capable. Other repairs thatmay be utilized for the transmission canbe found in Chapter 6, Section II.

LIMITATIONS: Small oil loss can betolerated. Inspect after every flight.

PERSONNEL/TIME REQUIRED:PROCEDURAL STEPS: (Refer to Figure 8-2.) . 1 Soldier

. 15 Minutes1. Cut lock wire.

MATERIALS/TOOLS REQUIRED:2. Remove electrical connector from . Solvent, Cleaner (item 7, Appx C)switch (8). . Tape, Army Green (item 50, Appx C)

or Equivalent3. Remove switch (8) and packing. . PlugRetain packing. . Safety Wire (item 26, Appx C)

8-11


PROCEDURAL STEPS:

1. Clean damaged area with solvent.

2. Close bullet hole with a plug andhold in place with tape.

3. Secure plug in place with safetywire.

NOTE

Because transmission is pressur-ized, try to center safety wireover plug.

4. Fill transmission with oil.

5. Inspect after every flight.


8-11. TAIL ROTOR GEARBOX, BULLET DAMAGE.

GENERAL INFORMATION: If a bullet strikesthe gearbox and exits and the gears donot jam, bind, or lose lubricant, repairmay be deferred.

LIMITATIONS: Small oil loss can betolerated. If aircraft is run for anextended period of time with little orno oil, gearbox will jam.


MATERIALS/TOOLS REQUIRED:. Solvent, Cleaner (item 7, Appx C). Rubber Sheet. Tape, Army Green (item 50, Appx C)

or Equivalent. Sealant (item 4, Appx C)

PROCEDURAL STEPS:

1. Clean damaged area with solvent ifavailable. Place a rubber sheet 1/2inch to 3/4 inch larger than hole undergreen tape. Alternatively, if rubbersheet not available, place sealant undertape.

2. Close bullet hole with green Armytape.

3. Inspect after every flight.


8-12

TM 55-1520-228-BD

CHAPTER 9

HYDRAULIC




Section I.

9-1. SCOPE. The OH-58 hydraulic systemoperates at pressures of 575 to 625 psi.This pressure is produced by thehydraulic pump (9, Figure 9-1). Thehydraulic fluid is routed to the flightcontrol servo actuators by means of flexhoses, tubes, mechanical valves, and anelectrically controlled solenoid.

9-2. GENERAL. This chapter containsfield fixes applicable only to the hosesand tubing which the hydraulic systemutilizes. Refer to Figure 9-2 forsystem fluid distribution.

9-3. ASSESSMENT PROCEDURES. NOassessment procedures are needed tolocate leaks and ruptured hoses and

Section II.

9-5. GENERAL.

a. Replacement lines may be manufac-tured in the field if materials andtools are available.

NOTE

Never discard MS fittings, theyare reusable. The MS21922sleeve is not reusable.

b. Replacement lines and hoses neednot be routed along the path of theoriginal installation. They may berouted along any convenient path as longas they do not interfere with personnelor with operating equipment. Long linesand hoses should be clamped to hard sup-ports at convenient intervals notexceeding 24 inches.

INTRODUCTION

lines. The location of a leak can onlybe determined by visual examination.Refer to Table 9-1 for assessment logicof the hydraulic system.


PARA.

Lines and Hose Replacement . .. 9-5 Tube Cutting . . . . . . . . . 9-6Aluminum Tubing Damage . . . . 9-7Hydraulic Hose Damage. . . . . 9-8O-Ring, Packing, and GasketApplication.. . . . . . . . 9-10

Hydraulic Fluid Substitutions. 9-11

LINES AND HOSES

c. It is considered quicker to make areplacement hose, using the old fittingif serviceable, than to repair a damagedhose. Flexible hose of braided stain-less steel with rubber center is used.There are two types of fittings used.One fitting is a socket and nippleassembly, Figure 9-3. The other typeis a nipple, o-ring, sleeve and socket,Figure 9-4.

9-6. TUBE CUTTING. When cuttingtubing, it is of utmost importance toproduce a squared end free of burrs.Tubing may be cut with a tube cutter ora hacksaw. The tube cutter is adaptablefor use with any metal tubing such assteel, titanium, or aluminum alloy.Place tubing in the cutting tool withthe cutting wheel at the point wherethe cut is to be made, Figure 9-5.

9-1

TM 55-1520-228-BDHYDRAULIC

1. Quick Disconnect (Pressure)2. Quick Disconnect (Return)3. Filter (Return)4. Filter (Pressure)5. Vent Line6. Reservoir7. Tachometer Generator8. Check Valve9. Hydraulic Pump

10. Case Drain Hose11. Solenoid Valve12. Hose (Return)13. Hose (Return)

14.15.16.17.18.19.20.21.22.23.24.25.

Hose (Pressure)Hose (PressureHose (Pressure)Hose (Return]pressure SwitchRelief ValveTo Servo Actuator (Collective)To Servo Actuator (Cycilc)Solenoid Valve Tee FittingHose Filter (Return)Hose Filter (Pressure)Hose, Pump inlet

Figure 9-1. Hydraulic System

9-2

1. Reservoir2. Baffle

8.9.

3. Scupper Drain 10.4. Quick Disconnects 11.5. Pump 12.6. Check Valve 13.7. Filter

Filter Bypass ValveRelief ValveSolenoid ValvePressure SwitchServo Actuator, CyclicServo Actuator,Collective

TM 55-1520-228-BD HYDRAULIC

Figure 9-2. Hydraulic System Schematic 9-3


Table 9-1. Assessment Logic

Figure 9-3. Two-Part Fitting

9-4


Figure 9-4. Four-Part Fitting

Figure 9-5. Using Tube Cutter

9 -5


Ratchet the cutter around the tubingapplying a light pressure to the cuttingwheel by intermittently twisting thesetscrew. Too much pressure on thecutting wheel could deform the tubing orcause excessive burring. After cuttingthe tubing, carefully remove any burrsfrom inside and outside of the tube. Ifa tube cutter is not available or iftubing of hard material is to be cut,use a fine toothed hacksaw, preferablyone having 32 teeth per inch. Aftersawing, file the end of the tube squareand smooth and remove all burrs. Besure all filings and cuttings areremoved from the tubing. Inspect thetubing end to verify its roundness, itsbeing cut square, and that it is cleanand free from marks and scratches.Figure 9-6 illustrates properly burredtubing.

NOTE

After tubing has been cut, allefforts should be made to flushany residue from the tube end.Flush with any available fluidor if end connections are inacces-sible, momentary activation ofthe system will suffice.

9-7. ALUMINUM TUBING DAMAGE.

GENERAL INFORMATION: Aluminum tubing issubject to damage by projectiles andfragments. Replacement with originalreplacement parts is desirable, but notessential. In BDAR, tubing and hose, ANand MS fittings, and other similar com-ponents can be substituted one for theother. Available time, tools, skills,and materials will determine whichrepair option to use. Whenever an alu-minum line has complex bends, replace-ment of the damaged section withhose, option 3, is probably thequickest fix.

OPTION 1: In Line Repair.

LIMITATIONS: None.

PERSONNEL/TIME REQUIRED:● 1 Soldier● 30 Minutes

MATERIALS/TOOLS REQUIRED:● 2 MS Unions● Splice Tube● Tubing Cutter● Knife or File● 4 MS Fittings

PROCEDURAL STEPS:

1. Cut and remove damaged section oftubing, Figure 9-7. Tube ends must besquare.

2. Clean ends of undamaged tubing withknife or file.

3. Measure the distance between the twoundamaged ends and prepare a tube splicereplacement section of this size. Cleanends of splice section as done in step 2.

4. Install an MS fitting on each endof the splice tube, Figure 9-8.

5. Insert the splice tube and tightenall fittings, Figure 9-9.


9-6


SECTION A-A

Figure 9-6. Properly Burred Tubing

Figure 9-7. Damaged Tube Section

9-7


Figure 9-8. Splice Repair Assembly

Figure 9-9. Repair Fitting and Tube Installation

9-8


OPTION 2: Substitute with High PressureHose (damage to section of tubing withbends).


MATERIALS/TOOLS REQUIRED: Hydraulic Hose Assembly Complete

with End Fittings 2 MS Unions 2 MS Fittings Tube Cutter Knife or File

PROCEDURAL STEPS:

1. Cut and remove damaged section oftubing, Figure 9-10. Tube ends must besquare.

2. Clean ends of undamaged tubing withknife or file.

3. Install MS fittings as shown inFigure 9-8.

4. Connect MS unions to both MSfittings and complete the repair byconnecting a hydraulic hose assemblyfrom one union to the other, Figure9-11. If the damaged length oftubing is long and more than onehose assembly is required, hoseassemblies may be spliced togetherwith unions. No harm will be doneif the replacement hose is too long.

5. Clamp at convenient intervals (notexceeding 2 feet) to rigid supports tosecure the line.

9-8. HYDRAULIC HOSE DAMAGE.

GENERAL INFORMATION: The hydraulichoses on the OH-58 are braided wirecovered rubber hose. Repair of damageor wear to the wire braids is deferrablefor one more flight, provided the rubberinner hose is not leaking underpressure. Inspect after every flight.If the inner rubber hose is leaking anda replacement assembly is not available,manufacture a new hose assembly. If anelbow fitting is not available, make anew hose with a large gentle loop so thehose will not kink. MS detachable fit-tings from a damaged hose may be reusedin the manufacture of a new assembly aslong as the threads and the seat are notdamaged. Swaged fittings cannot bereused.

OPTION 1: Install New Hose Assembly-BDARKit.

LIMITATIONS: None.


MATERIALS/TOOLS REQUIRED: Hydrualic Hose Assembly

PROCEDURAL STEPS:

1. Remove damaged hose assembly.

2. Install new hose assembly (BDAR kit).It may be necessary to splice two ormore hose assemblies together using MSunions to replace the damaged hoseassembly. No harm will be done if thereplacement hose is too long.


9-9


Figure 9-10. Damaged Tube Section-Complex Bends

Figure 9-11. Splice Adapter Assembly Installation

9-10


OPTION 2: Replace Hose Section with MSFittings (no BDAR hose assembliesavailable). For Teflon and rubber hose.

LIMITATIONS: None.


MATERIALS/TOOLS REQUIRED: Replacement Section of Hose or Tube

(if needed) Masking Tape (item 52, Appx C) Fine Toothed Hacksaw MS Fittings (socket, sleeve, and

female fitting, 4 ea.) MS Union (2 ea.)

PROCEDURAL STEPS:

1. Cut out damaged hose section. Wrapmasking tape (or other available tape)around hose over the areas where cutsare to be made to contain the braidedwires from unraveling. Mark on tapewhere the cuts are to be made. Hold ina vice and cut with a fine-toothedhacksaw. Take care to make square cut.Do not remove tape.

NOTE

If the damage is small, thelength of a single union may besufficient to provide a repair.However, if the damage is longer,a replacement section will berequired.

2. Obtain the proper sized MS fittingand unions.

3. Slip the MS socket over one of theundamaged ends of the hose, Figure 9-12.Use care not to unravel the wire braids.


4. Insert the MS sleeve between thewire braid cover and the inner rubberhose. Force onto hose until the edge ofthe sleeve is even with the end of therubber hose.

5. Reem inside end of Teflon hose witha square tool or a wooden plug so thatedge is smooth and flared to facilitateinsertion of the nipple of the MS femalefitting.

6. Slide the MS socket over end of hoseas far as it will go and hold in vise.Insert nipple of MS female fitting intorubber inner tube, Figure 9-13. Forceall the way until threads in socket andfemale fitting together and tightenuntil the gap between the edge of thesocket and the base of the femalefitting is approximately 0-1/32 inch forrubber and 0.025 to 0.045 inch forTeflon.

7. Prepare the other damaged end of thehose in the same manner.

8. If no replacement section isnecessary, connect the MS fittings onthe undamaged ends with an MS union,Figure 9-14.

9. If a replacement section is needed,obtain replacement section and cut todesired length. Refer to step 1 forprocedure for cutting hose. No harmwill be done if replacement section istoo long. Attach MS fittings to bothsides of the replacement section.

10. Place replacement section betweenthe undamaged ends and connect the MSfittings on the undamaged ends to thefittings on the replacement sectionusing MS unions.


9-11

TM 55-1520-228-BD

Figure 9-12. Installation of Socket and Sleeve

Figure 9-13. Assembly of MS Fitting

9-12


Figure 9-14. Union Connection

Section III. SEALS, PACKINGS, AND GASKETS

9-9. O-RING, PACKING, AND GASKETAPPLICATIONS.

a. O-rings are used in static anddynamic applications.

(1) In static applications, the o-ring serves as a gasket when it iscompressed within a recess. Leakage isnot normally acceptable.

(2) In dynamic applications, thesealing action is dependent primarily onthe resilience of the o-rings. Whenmoving parts are involved, minor seepagemay be normal and acceptable. A moistsurface found on moving parts of ahydraulic unit (piston shaft) is anindication that the seal is being pro-perly lubricated.

(3) Seal replacement is requiredwhen:

(a) The amount of fluid beinglost will cause system failure.

(b) The leak creates a hazard.

(c) The leak will not permitthe system to function safely for onemore flight.

NOTE

Packings and gaskets are identi-fied by part number on packages.Do not remove from package untilready for use.

9-13


b. Selection of Proper Packing orGasket. Selection of proper packing orgasket for a particular application isof the utmost importance. The exactsize, shape, and material compositionmust be properly determined in order forvarious systems to function correctly.Packings, gaskets, or seals like fit-tings are made to an AN, MS, or NASstandard. While gaskets may look alikein general construction features and maybe of the same size, they are notnecessarily interchangeable (Table 9-2).

c. The dimensional relationshipbetween AN6227, AN6230, and MS28775series o-ring packings and gaskets inthe various sizes are as follows:

AN6227-B1 through B7 are equivalentto MS28775-006 through -012.

AN6227-B8 through B14 are equivalentto MS28775-11O through -116.

AN6227-B15 through B27 are equivalentto MS28775-21O through -222.



AN6227B88 is equivalent to MS28775-425


9-10. HYDRAULIC FLUID SUBSTITUTIONS.

a. If the original specified fluid islost and standard replacement is notavailable, a substitute fluid must beused. Check Appendix D for a compatiblefluid. If a compatible fluid is notavailable, any available nonflammablelubricant can be used in a BDAR actionas a last resort.

CAUTION

O-rings, wipers, gaskets, or otherplastic or rubber parts of the hy-draulic system may swell or shrink,and for that reason continued oper-ability of the system cannot beguaranteed. Following such a sub-stitution, instructions for bringingthe system back to normal shouldinclude checking all moving partsof the hydraulic system and allhydraulic activated devices forproper operation and leaks. Wherefeasible, plastic and rubber partsshould be inspected for swelling,deformation, and other damage.

b. Record BDAR action taken. Whenmission is complete, as soon aspractical, repair the equipment/systemusing standard maintenance procedures.

9-14

●

●

●

●

●

●

●

Table 9-2. Seals Reference and Temperature Guides ChartMILITARY PARKER BASE TEMP GUIDE DURO-

SERIES COMPOUND POLYMER CONT SERV METER SERVICEAir Force and Navyhydraulic fluid

AN6227B MIL-P-5516 NITRILE MIL-H-5606, AN67230B Class B PS-01-30-5 (BUNA N) -65°F to +180°F 70 ! MIL-H-83282

NITRILEMS28775 MIL-P-25732 N304-7 (BUNA N) -65°F to +250°F 70MS29512 Air Force & NavyMS29513 NITRILE aircraft fuel2-, 3- MIL-P-5315 N602-7 (BUNA N) -65°F to +180°F 60 JP-4, JP-5

SyntheticMS29561 MIL-R-7362 NITRILE lubricantsNAS617 Comp.A, Type 1 47-071 (BUNA N) -65°F to +250°F 70 MIL-L-7808AN6290 Hydrualic oil,MS28778 NITRILE MIL-H-56062-, 3- MIL-P-551O N507-9 (BUNA N) -65°F to +180°F 90 MIL-H-83282NAS1593 MIL-R-25897 Fluoro-1 High temperature,NAS1595 CL 1 77-545 Elastomer -20°F to +400°F 70 fluid resistant.NAS1594 MIL-R-25897 Fluoro-1 High temperature,NAS1596 CL 2 V-377-9 Elastomer -20°F to +400°F 90 fluid resistant.

DESIGNATION PARKERSERIES ASTMID735-58T COMPOUND

2-, 3- SC720BCE1 E3 F2 C147-7

2-, 3- SC712BE1 E3 F2 C526-7

2-, 3- R81O B F2 F515-8

BASEPOLYMER

NEOPRENE

NEOPRENE

ETHYLENEPROPYLENE

TEMP GUIDE DURO- SERVICE ANDCONT SERV METER SPECIFICATIONS

Freon 12, weather& salt water

-65°F to +300°F 70 resistant. AMS3209General purposeindustrial

-65°F to +300°F 70 Neoprene. AMS3209Skydrol, Cellulube,& other phosphateesters, steam,water, air, dilute

-65°F to +300°F 80 acids & alkalis.

SPECIFICATION

9-15


Table 9-2. Seals Reference and Temperature Guides Chart (Cont)DESIGNATION PARKER BASE TEMP GUIDE DURO- SERVICE AND

SERIES ASTMID735-58T COMPOUND POLYMER CONT SERV METER SPECIFICATIONSMineral oil & hy-draulic fluid, water,

SB620 B E1 NITRILE steam, coolants,2-, 3- E3 F1 N525-6 (BUNA N) -40°F to +250°F 60 pneumatic service.

Petroleum baseMS9021 fuel & low tempera-MS9020 NITRILE ture resistance.2-, 3- SB712BE1 F2 N506-7 (BUNA N) -65°F to +225°F 65 AMS7271

Commercial gasoline,mineral oils &

NITRILE hydraulic fluids,2-, 3- SB715BE1 E3 F2 N103-7 (BUNA N) -65°F to +225°F 70 pneumatic service.

Mineral oil &hydraulic fluids,alkalies, gasolines,

NITRILE diesel oils,2-, 3- SB715BE1 E3 F1 N109-7 (BUNA N) -30°F to +250°F 70 pneumatics.AN1239XX Petroleum baseAN1240XX NITRILE fuel resistant.2-, 3- SB715B E1 E3 F2 N179-7 (BUNA N) -40°F to +250°F 70 AMS7270AN1238XX Petroleum baseAN1239XX NITRILE lubricating oil2-, 3- SB720B E1 F2 N180-7 (BUNA N) -20°F to +250°F 70 resistant. AMS7274

Listed by UnderwriterLaboratories for

NITRILE fuels, oils, and2-, 3- SB715E1 E3 F1 N214-7 (BUNA N) -40°F to +250°F 70 gasolines.

Mineral oils &hydraulic fluids,gasolines, pneu-

NITRILE matics, SAE 120R2-, 3- SB715BE1 E3 F1 N219-7 (BUNA N) -40°F to +250°F 70 Class 1, UL Listed.

TM 55-1520-228-BDHYDRAULIC9-16

Table 9-2. Seals Reference and Temperature Guides Chart (Cont)DESIGNATION PARKER BASE TEMP GUIDE DURO- SERVICE AND

SERIES ASTMID735-58T COMPOUND POLYMER CONT SERV METER SPECIFICATIONSWater service. Lowswell, extremely

SB71O B E1 NITRILE stable. Oil2-, 3- E3 F1 N398-7 (BUNA N) -40°F to +250°F 70 resistance.

For rotary seals.NITRILE Do not use with

2-, 3- SB820B E1 E3 F1 N256-8 (BUNA N) -20°F to +225°F 80 stainless steel.Mineral oils &

NITRILE hydraulic fluids,2-, 3- SB815BE1 E3 F1 N532-8 (BUNA N) -20°F to +250°F 80 gasoline, pneumatics.

Mineral oil &hy fluids, pneu-

NITRILE matics. High extru-2-, 3- SB915B E1 E3 N183-9 (BUNA N) -30°F to +250°F 90 sion resistance.

Mineral oil &NITRILE hydraulic fluids

2-, 3- SB915B E1 E3 N552-9 (BUNA N) -30°F to +250°F 90 pneumatics.Air & gases.

TA-605B E1 Static seal2-, 3- E3 F2 S418-6 SILICONE -80°F to +450°F 60 only. AMS3303

Air & gases.TA705B E1 Static seal

2-, 3- E3 LF2 S417-7 SILICONE -80°F to +450°F 70 only.Air & gases.

MS9068 TA-705BE1 Static seal2-, 3- E3 F2 S604-7 SILICONE -80°F to +450°F 70 only. AMS3304

High temperatureoils, aromatic

Fluoro-1 solvents, chemical2-, 3- None 77-545 Elastomer -20°F to +400°F 70 service. AMS7278

High temperatureoils, aromatic

Fluoro-1 solvents, chemical2-, 3- None V377-9 Elastomer -20°F to +400°F 90 service. AMS7278

TM 55-1520-228-BDHYDRUALIC9-17/(9-18 Blank)

TM 55-1520-228-BD

CHAPTER 10

INSTRUMENTS




There are no BDAR repairs offered for the instrument systems.

10-1/(10-2 Blank)

TM 55-1520-228-BD

CHAPTER 11

ELECTRICAL AND AVIONICS SYSTEM




Section 1.

11-1. SCOPE. This chapter providesmethods for assessing battle damage,deferring damage repair, and repairingelectrical and avionics systems.Extensive repairs to complicated com-ponents or line replaceable units (LRUs)are not expected to be made in thefield. Therefore, more emphasis isplaced on common repairs to intercon-necting cables and simple electrical andavionic components.

11-2. ASSESSMENT PROCEDURES.(See Table 11-1 for assessment logic.)

a. Wire Identification. The mostdifficult and time consuming part ofelectrical and avionics battle damageassessment is wire identification.Added and repaired wiring should beidentified to aid in troubleshooting.If time permits, tape or sleeving ateach end of added wiring of a materialsuitable for the ambient temperaturerange may be used. Typical wire andcircuit identification schemes are shownin Figure 11-1 and Table 11-2.Appendix F lists and depicts the majorcomponents, cable routes, and wiringterminations for the more complexavionics systems.

b. Circuit Function. The unitnumber and circuit designation letter

INTRODUCTION

It is used to distinguish between wiresin the same circuit. The wire segmentletter is used to distinguish betweenconductor segments (a wire segment be-tween two terminals or connections). Thewire size number is used to identify thegage of the wire or cable. The ground,phase, or thermocouple letter(s) areused as suffixes to the wire identifi-cation code to further identify certainwires. Ground wires are identified withan N suffix. Phase letters A, B, or Care added to identify the phase of wiresthat are in the three-phase wiring ofalternating current (AC) systems. Forthermocouple wire, the following suffixesare added to the identification code:AL (Alumel), CR (Chromel), FE (Iron),CN (Constantan), and CU (Copper).

c. Deferral. Repair of systems andsubsystems, which have adequate redun-dancy or are not critical to missionaccomplishment, may be deferred if safety of flight is not significantly degraded.Requirements must be examined to deter-mine if relaxed criteria for repair andaircraft performance can be accepted.The commander may defer combat main-tenance and battle damage repair, evenif doing so places operational limita-tions on the aircraft.

identify the type of circuits. The wirenumber consists of one or more digits.

11-1

TM 55-1520-228-BDELECTRICAL AND AVIONICS SYSTEM

Table 11-1. Electrical and Avionics Assessment Logic

Figure 11-1. Circuit Identification

11-2


Table 11-2. Function and Designation LettersCIRCUIT CIRCUITDESIGNATION DESIGNATIONLETTER CIRCUITS LETTER CIRCUITS

A ARMAMENT:Bomb suspension & releaseGunsChemicalRocketSightTurretWarningExternal pylons & storesJettison fuel tanksMine dispenser

B PHOTOGRAPHIC:Gun cameraMapping cameraReconnaissance cameraCamera intervalometerCamera doorsCamera heatersWarning

C CONTROL SURFACE:Horizontal stabilizerWarning

D INSTRUMENT (other than flightor engine instruments):AmmeterAir pressureFree air temperatureHydraulic pressureHorizontal position stabilizerVoltmeterClockWarning

E ENGINE INSTRUMENT:Tailpipe temperatureFuel flowFuel quantityFuel capacityOil temperatureOil pressureManifold pressureFuel pressureEngine oil quantityTachometerWarning

F FLIGHT INSTRUMENT:Bank and turnRate of climbDirectional gyroAir positionGround positionCompass (including flux gateand other stabilizedcompasses)

Gyro horizonAttitude gyroDriftmeterAltimeterAirspeedAccelerometerPitot-static tube meterWarning

H HEATING, VENTILATING, ANDDE-ICING:

Anti-icing (general)Battery heaterCabin heaterCigarette lighterDe-icing (general)Windshield defrosterWindshield defoggerWindshield de-icerHeater blanketOil immersion heaterRefrigerationVentilationWarning

I In order to avoid confusion withthe numeral one, the letter "I"shall not be used for circuit orcable identification.

J IGNITION:BoosterVibratorDistributorElectronicWarning

11-3


Table 11-2. Function and Designation Letters (Cont)CIRCUIT CIRCUITDESIGNATION DESIGNATION

CIRCUITS LETTER CIRCUITS

K ENGINE CONTROL:Blower ratioStarterWarning

L LIGHTING:ApproachFlasher-coderCockpitDriftCabinFormationCargoInteriorInstrumentSection (fuselage)LandingExteriorRunning, position, navigationPassingSearchTaxiWarning

M MISCELLANEOUS ELECTRIC:Windshield sprayWindshield wiperHoistEnclosure operationPositioner; seat, pedalSpecial test equipment

N UNASSIGNED

O In order to avoid confusionwith the numeral zero, theletter "O" shall not be usedfor circuit or cable identi-fication.

P DC POWER

Q FUEL AND OIL:Fuel valvesFuel booster-pump motorMoisture controlOil dilutionEngine primerFuel-transfer-pump motorand control

Fuel-loading-pump motor0il transfer-pump motorand controlOil booster pumpOil scavenge pumpThrottle controlFuel-pump motorOil diverterOil valvesWarning

R RADIO (Navigation andcommunication):

RA-Instrument landingRC-CommandRD-Radio direction findingRF-VHF liaisonRH-HomingRL-LiaisonRM-Marker beaconRN-NavigationRP-Special systemsRS-SHF commandRT-Radio teletypeRU-UHF commandRV-VHF commandRX-RecorderRZ-Interphone, headphone

11-4

LETTER


Table 11-2. Function and Designation Letters (Cont)CIRCUIT CIRCUITDESIGNATION DESIGNATIONLETTER CIRCUITS LETTER CIRCUITS

S RADAR:SA-AltimeterSF-InterceptSG-GunlayingSM-MappingSN-NavigationSQ-BombingSR-RecorderSS-SearchSV-Special systemsSW-WarningSX-Recognition (IFF)

T SPECIAL ELECTRONIC:TA-AdapterTB-Radar controlTC-Radio controlTD-Airborne announcingTE-Electronic countermeasureTF-Repeat backTG-GM homingTH-InfraredTK-TelemeteringTL-Attitude indicatorTM-Chaff dispenserTN-NavigationTP-Beacon (crash and locator)TQ-Transmitters and receiversTR-ReceiversTT-TransmittersTU-ReconnaissanceTW-Weather devicesTZ-Bombing devices

U MISCELLANEOUS ELECTRONIC:Electronic wiring for which no"R", "S", or "T" designation hasbeen assigned by the procuringactivity shall have the circuitfunction letter "U" assigned.Examples of wiring for whichthe circuit function letter "U"will be assigned are common leadsto electronic equipments andsystems interconnection wiringsuch as antenna or power circuitscommon to more than one equipmentor system.

V DC POWER and DC control cablesfor AC systems shall be identi-fied by the circuit functionletter "V."

W WARNING AND EMERGENCYEnclosure release and

locksFire extinguishersFlare releaseFire detectorIntercrew buzzer or light

X AC POWER:Wiring in the AC power systemshall be identified by thecircuit function letter "X."

Y ARMAMENT SPECIAL SYSTEMS:Y*A-Air to airY*B-Air to surfaceY*C-MultimodeY*M-Missile-guidanceY*T-Turret* Armament special

system number

Z UNASSIGNED

11-5



PARA.

Splicing Unshielded Wires. . . 11-5Wire Repair Segments,

RG-124/U, RG-142 B/U,RG-302/U, and RG-303/U . . . 11-16

Section II. ELECTRICAL

11-4. GENERAL. The objective ofelectrical and avionics system battledamage repair is to restore damagedcircuits which are mission essential.It is also used to make nonessentialcircuits safe. The repair procedures inthis section are designated to quicklyreturn an aircraft to a flyable con-dition.

a. Electrical and Avionics Repairs.Electrical and avionics equipmentreceiving significant battle damage willusually not be repairable. The equip-ment may require replacement to meetmission requirements. When replacementfor nonessential system units are notavailable, the technician should, whenpossible, make the necessary repairs oradjustments on the unit for one morecombat sortie. Avionics wiring, coaxialcables, and general aircraft wiring canbe repaired using a variety of proce-dures and materials. Most of thesetechniques are considered standard for

PARA.

Coax Splice for RG-9 B/U,RG-214/U, RG-225/U, andRG-393/U . . . . . . . . . . 11-17

Coax Splice for RG-58 C/U,RG-233/U, RG-59 B/U, andRG-71 B/U . . . . . . . ..11-18

Component Bridging . . . . . . 11-19Connector Repair . . . . . . . 11-20Circuit Protection Device

Repair. . . . . . . . . . . 11-21Bus Bars . . . . . . . . . . . 11-22Battery Repair BB-476/A. . . . 11-23Damaged or Defective Power

Relays. . . . . . . . . . . 11-24Substitute Emergency Antenna,

Field Expedient. . . . . . . 11-25Typical Avionics Configuration 11-26BDAR Kits . . . . . . . . . . .11-27

AND AVIONICS WIRING DAMAGE

temporary repairs. Appendix F lists anddepicts the major components, cableroutes, and wiring terminations for themore complex avionics systems.

b. Isolation of NonessentialSystems. To isolate damaged non-essential system wiring use crimp-onend caps, tape, or other insulatingmethod. Secure wires to structure.

c. BDAR Electrical Wiring SystemRepair Definitions and Capabilities.The BDAR wiring repair set providesfor two types of aircraft electricalwiring repairs classified as"PERMANENT," or "TEMPORARY."

(1) A permanent repair returns theelectrical wiring system to full capabi-lity as manufactured with no degrada-tion of any system operating charac-teristics. No periodic inspection orreplacement is required with a permanentrepair.

11-6

Unshielded Wires . . . . . . 11-6Damaged Wire Insulation . . . . 11-7Shielded Cable Repair . . . . . 11-8Shielded Cable Repair Segments 11-9Shield Terminators . . . . . . 11-10Terminators for Nickle-PlatedShields ( includingvermillion). . . . . . . . . 11-11

Terminal Boards. . . . . . . . 11-12Terminal Lugs. . . . . . . . . 11-13Wire Bundle Tie Wraps. . . . . 11-14Coax Splice for RG-136/U

and RG-179 B/U . . . . . . . 11-15Coax Splice for RG-180 B/U,

TM 55-1520-228-BD

(2) A temporary repair returns theelectrical wiring system to a reducedlevel of capacity with a possible slightreduction of system operational capabi-lity. Temporary repairs must bereinspected at 100 flight hours. Atthis time, a permanent repair will beperformed or an extension of use for thetemporary repair will be granted.

NOTE

Temporary repairs establishedin the TM will only be appliedin time of war. The commanderor his designated representa-tives may authorize deviationsnecessary to accomplish wartimerequirements.

d. Repair Techniques.

(1) In battle, situations mayarise that will require the assessor andrepair personnel to develop innovativerepair techniques. This section des-cribes and illustrates some repair capa-bilities to broken and/or damaged wires,shielded or coaxial cables, electricalconnectors, and associated electricalcomponents in the combat environment.

(2) Prior to performing any of thelisted repairs, the repair technicianmust be knowledgeable in the applicationof the basic repair procedures and pro-ficient in the use of wiring repairtools and materials.

11-5. SPLICING UNSHIELDED WIRES.

GENERAL INFORMATION: This procedureprovides for repairing damagedunshielded wires.

WARNING

Do not be misled by the term "lowvoltage." Potentials as low as50 volts may cause death underadverse conditions.


CAUTION

Make sure aircraft power is off.Disconnect battery beforetouching any wires.

OPTION 1: Crimp Splicing.

LIMITATIONS: Only to be used for wiresizes 12-26. Where no more than onesplice is made per 10 feet of wire, itis a permanent repair.


MATERIALS/TOOLS REQUIRED:Appropriate Size Splice (item 10,

Appx B)Appropriate Size Sealing Sleeve

(item 10, Appx B)Crimping Tool (item 10, Appx B)Strippers (item 10, Appx B)Heat Gun (item 10, Appx B)Reflector (item 10, Appx B)

PROCEDURAL STEPS:

1. Strip wires, refer to Table 11-3.

WIRESIZE

20-2616-1812-1420-2616-1812-14

Table 11-3. Unshielded Crimp

STRIPPINGLENGTH ,INCHES

.25-.30

.30-.35

.30-.35

.25-.30

.30-.35

.30-.35

>125>125>125<105<105<105

2. Slide sealing sleeve onto one of thewires, Figure 11-2. On wire rated at 125°C or above, insert one prepared wireinto small end of sealing sleeve andpush crimp barrel out.

3. Crimp wires with crimp tool.

11-7

Splice ApplicationT E M P .RATINGDEG. C


Figure 11-2. Crimp Splice

11-8


4. Shrink sealing sleeve over crimpwith heat gun. Use reflector, tem-perature set at 900°F.


OPTION 2: Terminal Lug Splicing.

LIMITATIONS: Only to be used on wiresizes AWG No. 10 and smaller. This is atemporary repair.

PERSONNEL/TIME REQUIRED: 1 Soldier

15 Minues Per Splice

MATERIALS/TOOLS REQUIRED: Terminal Lug Barrel Insulating Sleeve and Tie Wraps or

Heat-Shrinkable Insulation Crimp Tool

PROCEDURAL STEPS:

1. Select a terminal with a barrellarge enough to accommodate both wires.

2. Cut off terminal lug tongue.

3. Prepare wire ends.

4. Slip an insulating sleeve 1 inchlonger than terminal lug barrel over theend of one of the wires, and insert wireend into the barrel as shown in Figure11-3.

5. Crimp barrel in center.

6. Slide insulating sleeve over theterminal lug barrel splice, and securein place by using tie wraps or heatingif heat-shrink sleeve is used.


OPTION 3: Split Bolt Splice Connectors.

LIMITATIONS: Only to be used on wiresizes AWG No. 4 through No. 10. Inspectafter every flight.


10 Minutes

MATERIALS/TOOLS REQUIRED: Strippers or Knife (item 10, Appx B) Heat–Shrinkable Tubing

(item 10, Appx B) Split Bolt Splice Connector

(item 10, Appx B) Heat–Shrinkable Tape (item 10, Appx B) Reflector (item 3, Appx B)

PROCEDURAL STEPS:

1. Slide a 3 inch length of largediameter, heat-shrinkable tubing overone of the wires to be spliced.

2. Strip wires and insert into the con-nector from opposite sides.

NOTE

Conductors may be folded back oneor more times to fill the connec-tor opening and provide firmclamping.

Strip wires 1/2 inch if foldingback is not required. Strip wires 1-1/4 inch if singlefolding back is required.

Strip wires 2-1/2 inch if doublefolding back is required.

3. Tighten nut securely.

4. Wrap the splice with heat-shrinkabletape. Cover all metal parts and overlaponto insulation.

5. Heat the end of the tape to softenthe adhesive layer and press it intoposition while warm. Use reflector(located in A5 of wiring kit), tem-perature set at 900°F.

11-9


Figure 11-3. Splicing with Terminal Lug Barrel

6. Heat the tape to shrink it onto thesplice and soften the adhesive layer.Use reflector (located in A29 of wiringkit), temperature set at 900°F.

7. Center the heat-shrinkable tubingover the splice.

8. Heat the tubing to shrink it ontothe splice. Use reflector (A29), tem-perature set at 900°F. Begin in themiddle and work toward the ends. Tubingmay not shrink completely onto the wireinsulation, this is normal.


OPTION 4: Twist Wire.

LIMITATIONS: This is a temporary typerepair.

PERSONNEL/TIME 1 Soldier

10 Minutes

MATERIALS/TOOLS REQUIRED: Tape, Electrical (item 46, Appx C) Strippers or Knife

PROCEDURAL STEPS:

1. Cut ties and work broken wire tothe outside of the bundle.

2. Pull sufficient slack from the wirerun toward the break so that there willbe no strain on the splice.

3. Wipe wire clean with a clean, dryrag or a rag dampened with 1-1-1 trich-loroethane, alcohol, or equivalent.

4. Trim broken ends of the wire.

5. Split all the wire ends.

6. Split the strands of wire apart andtwist the matching wires together asshown in Figure 11-4.

7. Cover each individual splice withelectrical tape. Insure no metal con-tact between adjacent splices.

11-10


Figure 11-4. Twist Wire Repair

8. Cover splice area with electricaltape.

9. If a section of wire needs to bereplaced, a double repair can be made,Figure 11-5.


OPTION 5: Casing Splice Method.

LIMITATIONS: This is an emergency typerepair for one time flight only.


10 Minutes

MATERIALS/TOOLS REQUIRED: Cylindrical metal casing such as ball

point pen refills, expendedcartridges, etc.

Insulation Sleeve or Tape(item 10, Appx B)

Crimp Tool (hammer, pliers, etc.) Wire (item 10, Appx B)

PROCEDURAL STEPS:

1. Fabricate splices approximately 1 to2 inches long from small metal casing.

NOTE

Ball point refills or expendedcartridge shell casings, when cutto length, make excellent spli-ces, Figure 11-6.

2. Strip 1/2 to 1 inch insulation fromboth ends of wire to be spliced.

3. Insert wires into casing splice andcrimp tightly with pliers or a hammer andsmall iron bar.

11-11


Figure 11-5. Replacement Section; Twist Wire Repair

Figure 11-6. Metal Casing Splice Repair

11-12


4. Insulate with tape or use plasticand string. Tie in place.


OPTION 6: Bolted Terminal Lug.

LIMITATIONS: This is a temporary typerepair.


10 Minutes

MATERIALS/TOOLS REQUIRED:Appropriate Size Terminal Lugs,

2 ea. (items 54, 55, 56,57, 58, Appx C)

Screw or BoltNutWasherLockwasherInsulating Sleeve orTape (item 52, Appx C)

PROCEDURAL STEPS:

1. Cut ties and work broken wire to theoutside of the bundle.


3. Wipe wire clean with a clean, dryrag or a rag dampened with 1-1-1 tri-chloroethane, alcohol, or equivalent.

4. Trim broken ends of wire, andinstall an insulating sleeve over oneend of the wire and slide back and outof the way for now.

5. Strip both wire ends and crimp aninsulated terminal lug of the propersize to each wire end.

6. Bolt terminal lugs together as shownin Figure 11-7.

7. Slide the insulating sleeve over thesplice so that the ends of the insu-lating sleeve extend at least 3/4 of aninch beyond the ends of each terminallug. Secure both ends of the insulationwith tie wraps or string ties as shownin Figure 11-7.

8. If a section of wire needs to bereplaced, a double repair can be made tobridge the ends of the original wireback together, Figure 11-8.


OPTION 7: Metal Clamp Method.

LIMITATIONS: This is an emergency typerepair.


10 Minutes

MATERIALS/TOOLS REQUIRED: Screw Clamp, Control Cable Clamp, or

Safety Wire (item 26, Appx C) Insulating Sleeve or Electrical

Tape (item 49, Appx C) Knife Cable Ties (item 10, Appx B)

PROCEDURAL STEPS:

1. Cut ties and work broken wire to theoutside of the bundle.


3. Wipe wire clean with a clean, dryrag or a rag dampened with 1-1-1 tri-chloroethane, alcohol, or equivalent.

4. Trim broken ends of wire.

5. Remove 2 inches of wire insulationfrom each end of the damaged wire.

11-13


Figure 11-7. Bolted Terminal Lug Repair of Large Wires

Figure 11-8. Replacement Section; Terminal Lug Repair

6. Ram or push the two wire ends together sothat the strands interlink.

7. Secure with screw clamp, control cable clamp,safety wire, or other suitable means, Figure 11-9.

8. Insulate with tape or insulation sleeve.

9. Record BDAR action taken. When mission iscomplete, as soon as practical, repair theequipment/system using standard maintenanceprocedures.

Figure 11-9. Ram Wire Repair Method

11-14


11-6. WIRE REPAIR SEGMENTS, UNSHIELDEDWIRES.

GENERAL INFORMATION. The BDAR electri-cal wiring kit has wire replacementsegments for replacement sections up to9 inches in length. The replacementsections are located in the wire repairkit. Refer to Table 11-4.

CAUTION

Make sure aircraft power is off.Disconnect battery beforetouching any wires.

LIMITATIONS: Dependent on splice methodused to connect replacement segment.


20 Minutes

MATERIALS/TOOLS REQUIRED: Replacement Segment (Refer to Table

Table 11-4) Splice (item 10, Appx B) Insulation Sleeve or Tape (item 49,

Appx C) Crimp Tool (item 10, Appx B)

11-7. DAMAGED WIRE INSULATION.

GENERAL INFORMATION: If the wire insu-lation is damaged but the wire itself isnot, repair of the insulation may beaccomplished by installing heat-shrink-able tape, a transparent sleeve offlexible tubing, and securing withnylon braid or some other means.

CAUTION

Make sure aircraft power is off.Disconnect battery beforetouching wires.

OPTION 1: Heat-Shrinkable Repair Tape.

LIMITATIONS: This is a temporaryrepair.


10 Minutes

MATERIALS/TOOLS REQUIRED: Heat-Shrinkable Tape (item 10, Appx B) Reflector (item 10, Appx B) Heat Gun/Heat Source (item 10, Appx B)

PROCEDURAL STEPS:PROCEDURAL STEPS:

1. Start wrapping tape at one end of1. Cut out damaged wire (up to 9inches in length).

2. Strip wires, refer to Table 11-4.

3. Splice replacement segment ontodamaged wire using one of the optionsin paragraph 11-9.


area to be covered.

2. Overlap each turn about one-third oftape width. Overlap of more than 50 per-cent or multiple wraps are not recom-mended. Excess thickness prevents heattransfer to the inner layer. Refer toFigure 11-10.

3. Apply heat to end of last lap tosoften the meltable adhesive, and pressit into position while warm. Usereflector (A5), temperature set at 900°F.

11-15


4. Heat the tape to shrink it and meltthe adhesive layer. Use reflector(A29), temperature set at 900°F.


Table 11-4. Wire Repair SegmentsI

Figure 11-10. Heat-Shrinkable Tape

OPTION 2: Insulation Sleeve.



10 Minutes

MATERIALS/TOOLS REQUIRED: Insulation Sleeving (item 10, Appx B) Knife String, Nylon Braid, or Tie-Wraps.

(item 10, Appx B)

PROCEDURAL STEPS:

1. Remove damaged insulation andexamine to insure center conductor isnot damaged.

2. Prepare a transparent sleeve offlexible tubing 1-1/2 times the outsidediameter of the wire and 2 inches longerthan the damaged portion of the insula-tion.

3. Split lengthwise and wrap 1-1/2times around the wire at the damagedsection.

4. Tie with string or other suitablematerial at each end and at 1 inchintervals over the entire length, Figure11-11.


Figure 11-11. Insulation Repairwith Sleeving

OPTION 3: Tape Insulation.


PERSONNEL/TIME REQUIRED: 1 Soldier 5 Minutes Per Wire

MATERIALS/TOOLS REQUIRED: Tape, Electrical (item 49, Appx C) Knife

11-16

PROCEDURAL STEPS:

1. Remove damaged insulation andexamine to insure center conductor isnot damaged.

2. Wrap tape over exposed center con-ductor of wire. Tape should extend 2inches over the wire insulation at eachend of the area to be covered.

3. Record BDAR action taken. Whenmission is completed or as soon asfeasible, repair using standard main-tenance procedures.

OPTION 4: Potting Compound Insulation.


PERSONNEL/TIME REQUIRED: 1 Soldier 1-3 Hours Per Wire (Depending on whichpotting compound is used.)

MATERIALS/TOOLS REQUIRED: Potting Compound Insulation (RTV-730,

MIL-S-8516, synthetic rubber, orequivalent)

Knife

PROCEDURAL STEPS:

1. Remove damaged insulation and exa-mine to insure center conductor is notdamaged.

2. Apply a thin coat of potting com-pound over the exposed center conductor.

3. Allow time to dry. If compoundcoating does not seem to be sufficient,apply additional layers as needed.



11-8. SHIELDED CABLE REPAIR.

GENERAL INFORMATION: The following pro-cedures may be used to repair severedshielded cables.

OPTION 1: Shielded Cable Splice.

LIMITATIONS: Repair is good for cablesrated at 125°C

PERSONNEL/TIME 1 Soldier 15 Minutes

or above.

REQUIRED:

MATERIALS/TOOLS REQUIRED: Appropriate Size Splice

(item 10, Appx B) Appropriate Size Sealing Sleeve

(item 10, Appx B) Crimping Tool (item 10, Appx B) Strippers (item 10, Appx B) Heat Gun (item 10, Appx B) Reflector (item 10, Appx B)

PROCEDURAL STEPS:

1. Prepare cable for splice. Refer toFigure 11-12 and Table 11-5.

NOTE

Refer to Table 11-5. for X, Y, and Z

Figure 11-12. Shielded CableRepair Preparation

11-17


Figure 11-13. Shielded Cable Splice Preparation

Table 11-5. Shielded Cable Repair

2. Slide the shield sleeve onto one ofthe cables.

3. Slide the inner sealing sleeve ontothe primary wires of one of the cables,then insert the other primary wire ontothe other end of the inner sealingsleeve and crimp with AD-1377 crimptool, located in electrical wiringkit. Refer to Figure 11-13.

4. Shrink the inner sleeve of thesplice with temperature set at 900°F.Keep hot air away from shield sleeve.

5. Center and shrink the shield overthe splice area so that the soldermelts and flows. Shield sleeve braidmust overlap cable braid at both ends.Refer to Figure 11-14.

OPTION 2: Sheath Connector andGrounding Sheath.

LIMITATIONS: This is a temporaryrepair until heat shrink is installed,then it is a permanent repair.

PERSONNEL/TIME REQUIRED: 1 Soldier 1/2 Hour Per Wire

MATERIALS/TOOLS REQUIRED: Insulating Sleeving, Heat Shrink, or

Tape (item 49, Appx C) Knife String, Nylon Braid, or Tie Wrap (to

be used if insulating sleeve is used) 2 Sheath Connectors (item 10, Appx B) Grounding Sheath (item 10, Appx B) Center Conductor Splice (item 10, Appx B)

11-18


Figure 11-14. Shielded Cable Spliced

PROCEDURAL STEPS:

1. Select a grounding sheath.

2. Prepare the severed ends of thecable for application of a groundingsheath connector, Figure 11-15, step a.

3. Position sheath connector andgrounding sheath as shown in Figure11-15, step b. (NOTE: Crimp sheath con-nector and grounding sheath only at oneside at this time.)

4. Slide insulating sleeve overuncrimped sheath connector as shown inFigure 11-15, step b. (NOTE: If insu-lating sleeve is not available, use heatshrink or alternate insulation such aselectrical tape.)

5. Splice center conductor using a per-manent splice or by using one of thesplicing procedures in paragraph 11-9.

6. Push the free end of the groundingwire into the uncrimped grounding sheathconnector. Crimp securely, Figure 11-15,

7. If an insulating sleeve is used,slide into place and tie both endsFigure 11-15, step d. If heat shrink isused, slide into place and shrink intoposition. If tape is used, use it tocover repair.


OPTION 3: Pigtailed Sheath Method.



MATERIALS/TOOLS REQUIRED: Knife Insulating Sleeving or Tape

(item 49, Appx C) String, Nylon Braid, or Tie Wrap (to

be used if insulating sleeve is used) Center Conductor Splice

step c. (item 10, Appx B)

11-19


Figure 11-15. Shielded Cable Repair

11-20

PROCEDURAL STEPS:

1. Prepare severed ends of cable forpigtail method of shield terminations,Figure 11-16, step a.

2. Splice center conductor, Figure11-16, step b, using a permanent spliceor by using one of the splicing proce-dures in paragraph 11-9.

3. Use two splice connectors to addshort length of insulated wire as exten-sion to complete shield connection,Figure 11-16, step b.

4. Insulate repair, Figure 11-16,step c.


OPTION 4: Substitute Shielded Braid.



MATERIALS/TOOLS REQUIRED: Substitute Shielded Braid

(item 10, Appx B) Knife Center Conductor Splice

(Item 10, Appx B) Metal Screw Clamp, Sheath Connector,

or Equivalent

PROCEDURAL STEPS:

1. Prepare severed ends of cable forapplication of repair splice andshielding, Figure 11-17, step a.

2. Select suitable shielding materialand slide over one end of severed cable.


Shielding must be long enough to overlapthe shielding on both sides of the cablebeing repaired after the center conduc-tor is repaired. Shielding material canbe obtained from another shield cable orground cable material.

NOTE

It is essential that the shielding,as well as the inner conductor, berepaired properly to prevent elec-tromagnetic interference (EMI)problems.

3. Splice center conductor using a per-manent splice or by using one of thesplicing procedures in paragraph 11-9,Figure 11-17, step b. Insure centerconductor is insulated from shield.

4. Slide shielding material overrepaired inner conductor and clamp atshielding overlap areas, Figure 11-17,step c.


11-9. SHIELDED CABLE REPAIR SEGMENTS.

GENERAL INFORMATION: The electricalwiring kit has wire replacement segmentsto replace segments up to 9 inches inlength.

CAUTION

Make sure aircraft power is off.Disconnect battery before touchingany wires.

LIMITATIONS: Dependent on splice methodused to connect replacement segment.

PERSONNEL/TIME REQUIRED: 1 Soldier 1 Hour

11-21


PIGTAILS

STEP A

STEP B

Figure 11-16. Pigtail Method Repair

11-22


Figure 11-17. Substitute Shielded Braid Repair

11-23


MATERIALS/TOOLS REQUIRED: Replacement Segment (item 10, Appx B) Stripper or Knife Splice (item 10, Appx B) Insulation Sleeve (item 10, Appx B) Crimp Tool

PROCEDURAL STEPS:

1. Cut out damaged cable (up to 9inches in length).

2. Prepare cable for splice. Refer toFigure 11-12 and Table 11-5.

3. Use one of the options of paragraph11-5 to splice the ends of the replace-ment segment onto the damaged cable.


11-10. SHIELD TERMINATORS.

GENERAL INFORMATION: The kit containsvarious types of shield terminators forshielded cable.



15 Minutes

MATERIALS/TOOLS REQUIRED: Shield Terminator (item 10, Appx B) Reflector Heat Gun/Heat Source Stripper or Knife Insulating Sleeve (item 10, Appx B)

PROCEDURAL STEPS:

1. Prepare cableFigure 11-18.

for repair. Refer to

Figure 11-18. Shield TerminatorRepair Preparation

2. Position shield terminator on cableas shown in Figure 11-19. (Select thesmallest terminator that slides easilyover the prepared cable.)

3. Heat shield terminator until soldermelts and flows into wire strands, redcolor disappears, and seals melt andflow at both ends. Use reflector withshield terminator of wire repair kitwith temperature set at 900°F.

4. Terminate the ground lead asdirected in aircraft wiring manual.


11-24


WINDOW STRIP

END STRIP

END STRIP BRAID FOLDED BACK

Figure 11-19. Shield Terminator Repair

11-11. TERMINATORS FOR NICKEL-PLATEDSHIELDS (INCLUDING VERMILLION).

GENERAL INFORMATION: The kit containsshield terminators for nickel-platedshields, including vermillion.

LIMITATIONS: This is a permanent repair.


15 Minutes

MATERIALS/TOOLS REQUIRED: Shield Terminator (item 10, Appx B) Reflector (A3) (item 10, Appx B) Heat Gun/Heat Source Stripper or Knife Insulating Sleeve (item 10, Appx B)

PROCEDURAL STEPS:

1. Prepare cableFigure 11-20.

for repair. Refer to

2. Position ground lead and shield ter-minator as shown in Figure 11-21.

3. Heat shield terminator until solderring melts; then, continue heating for anadditional 15 seconds or until sleevestarts to turn brown. Use reflectorwith temperature set at 900°F.

4. Terminate the ground lead asdirected in the aircraft wiring manual.


.25-.30" .25-.30"

WINDOW STRIP END STRIP

Figure 11-20. Nickel-Plated ShieldTerminator Preparation

Figure 11-21. Nickel-Plated ShieldTerminator Repair

11-25

TM 55-1520-228-BD ELECTRICAL AND AVIONICS SYSTEM

11-12. TERMINAL BOARDS.

GENERAL INFORMATION: The terminalboards provided are all 5 inches inlength. They are located in the wiringkit. They can be cut to shorterlengths using a hacksaw. The generalprocedure is as follows:

LIMITATIONS: Permanent repair.

PERSONNEL/TIME REQUIRED: 1 Soldier Time will depend on the

wires on the terminalquestion.

MATERIALS/TOOLS REQUIRED:

number ofboard in

Replacement Terminal Board(item 10, Appx B)

PROCEDURAL STEPS:

1. Tag and disconnect wires one at atime.

2. Remove terminal board.

3. Install replacement terminal board.

4. Connect wires to duplicate theoriginal installation.


11-13. TERMINAL LUGS.

GENERAL INFORMATION: Terminal lugs areprovided in the wiring kit, Table 11-6.The general procedure for installingterminal lugs is as follows:

LIMITATIONS: None


MATERIALS/TOOLS REQUIRED: Strippers or Knife Replacement Terminal Lug (Table

11-6) Crimp Tool (item 10, Appx B)

PROCEDURAL STEPS:

1. Select a terminal to fit both thewire and the terminal stud, Table 11-6.

2. Strip the wire to the lengthspecified in Table 11-6.

3. Open the dies of the crimp tool.Refer to Figure 11-22.

4. Place terminal in proper cavity ofcrimp tool dies (see Detail A of Figure11-22). Sizes are stamped below eachcavity on side of die.

Figure 11-22. Terminal Lug Repair

11-26

WIRESIZE

24

22

20

18

16

14

ITEM

B30

B31

B32

B33

B34

B35

4 M7928/1-7M7928/1-8M7928/1-9

8 M7928/1-1410 M7928/1-15

1/4 In. M7928/1-166 M7928/1-218 M7928/1-2310 M7928/1-24

810

1/4 In68

101/4 In.

810

1/4 In.

M7928/1-32M7928/1-33M7928/1-34M7928/1-39M7928/1-41M7928/1-42M7928/1-43M7928/1-48M7928/1-50M7928/1-51M7928/1-52

WIRESTRIPLENGTH(IN)

.15

.19

.25

5. Locate terminal with locator (detailB). Terminal should locate with flangeover the top of the locator.

6. Insert wire to proper depth.

7. Close handle of tool until dies areclosed and ratchet releases. The crimpis now complete (see detail C).


11-14. WIRE BUNDLE TIE WRAPS.

GENERAL INFORMATION: After wire damagerepairs are made, insure minimum essen-tial cable clamps, lugged bundle ties,and unlugged wire bundle ties arereplaced.


OPTION 1: Self-Clinching Cable Straps.

LIMITATIONS: These straps are not to beused under the following conditions:

In temperature environments whichexceed 85°C (185°F).

On coaxial cables or bundles con-taining coaxial cables which do not havehard dielectrics.

In areas where excess material fromstrap cuttings or failure of the mountedstrap would allow plastic to fall intomoving mechanical parts.

On the outside of cables or bundlesthat will be dragged through tight orunreachable spaces during final aircraftinstallation.

Where failure of the strap would per-mit movement of the wiring against partswhich could damage the insulation orallow wiring to foul mechanical linkages.

In high vibration areas.

In areas of severe wind or moistureproblems.

When use of these straps is preventedby these restrictions, use tie tapefor secondary ties between clamps.

PERSONNEL/TIME REQUIRED: 1 Soldier 1 Minute

MATERIALS/TOOLS REQUIRED: Self-Clinching Cable Strap

(item 10, Appx B) Cable Strap Tool (item 10, Appx B)

PROCEDURAL STEPS:

1. Position the strap around the bundlewith the flat side of the large endagainst the bundle.

11-27

68

10 M7928/1-10

1/4 In. M7928/1-256 M7928/1-30

6

P/NS T U DS I Z E


2. Thread tip through eye then handpull strap tight against the bundle.Refer to Figure 11-23.

3. Adjust the tool tension setting to 7.

4. Pass the free end of the cable tiethrough the slot in the end of the toolthen push tool snugly against the strap,Figure 11-24.

5. While holding strap firmly againstside of tool and tool faces squarelyagainst large end of strap, pump handleseveral times without fully activatingthe tool's cutting knife. Once thestrap has been stretched to its maximum,squeeze handle slowly and firmly untilstrap is cut.

The strap must be cut flush withthe surface in order to eliminatepainful cuts and scratches fromprotruding strap ends.

6. If strap end is not cut flush,remove the strap and install a new strapin its place.

7. Pick up for appropriate disposal allbroken straps and strap ends that werecut off.

Figure 11-24. Self-Clinching CableStrap and Tool

OPTION 2: Tie Tape.

LIMITATIONS:

1. Do not use ties on that part of awire group or bundle located inside aconduit.

2. When tying wire bundles behind con-nectors, start ties far enough back fromthe connector to avoid splaying of con-tacts.

PERSONNEL/TIME REQUIRED: 1 Soldier 1 Minute Per Tie

MATERIALS/TOOLS REQUIRED: Tie Tape (item 10, Appx B)

8. Record BDAR action taken. When PROCEDURAL STEPS:mission is complete, as soon aspractical, repair the equipment/system 1. Tie bundles tightly enough to pre-using standard maintenance procedures. vent slipping, but not so tightly that

the tape cuts into or deforms the insu-lation. Be especially careful whentying coaxial cable which has a softdielectric insulation between the innerand outer conductors.

2. Use knot shown in Figure 11-25.

3. Tie all wire groups of bundles wheresupports are more than 12 inches apart.Space ties 12 inches or less.

Figure 11-23. Self-Clinching Cable Strap

11-28

WARNING


Figure 11-25. Tie Tape Repair Procedure


NOTE

Harness branches can be securedby tying.

OPTION 3: String or Wire Repair.


PERSONNEL/TIME REQUIRED: 1 Soldier 1 Minute

MATERIALS/TOOLS REQUIRED: Wire or String

PROCEDURAL STEPS:

1. Tie wires or groups using type knotshown in Figure 11-25.

CAUTION

Do not tighten wire or string toomuch, as wire or string can cutinto or deform insulation.

2. Space ties at 12 inches or less.


11-15. COAX SPLICE FOR RG-136/U ANDRG-179B/U.

GENERAL INFORMATION: There are variouscoax splices in the wiring repair kitthat may be used for the different typesand sizes of coax cable.



MATERIALS/TOOLS REQUIRED: Coax Splice (item 10, Appx B) Stripper or Knife Crimp Tool, AD-1377 (item 10, Appx B) Reflector (item 10, Appx B) Heat Gun/Heat Source (item 10, Appx B)

PROCEDURAL STEPS:

1. Prepare coax cable, Figure 11-26.Refer to Table 11-5.

Figure 11-26. Coax Splice Preparation

11-29


2. Slide the shield sleeve and innersleeve onto one of the coaxial cablesin the order given.

3. Splice the center conductor. Usethe red cavity of the crimp tool.

4. Shrink the inner sleeve over thesplice, Figure 11-27. Use reflector,temperature set at 900°F. Keep the hotair away from shield sleeve.

5. Center and shrink the shield sleeveover the splice area so that the soldermelts and flows, Figure 11-28. Shieldsleeve braid must overlap coax braid atboth ends. Use reflector, temperatureset at 900°F.


11-16. COAX SPLICE FOR RG-180B/U,RG-124/U, RG-142B/U, RG-302/U, RG-303/U.

GENERAL INFORMATION: There are variouscoax splices in the wiring repair kitthat may be used for the differenttypes and sizes of coaxial cable.


MATERIALS/TOOLS REQUIRED: Crimp Tool, AD-1377 (item 10, Appx B) Coax Splice (item 10, Appx B) Stripper or Knife Reflector (item 10, Appx B) Heat Gun/Heat Source (item 10, Appx B)

PROCEDURAL STEPS:


2. Slide shield sleeve, inner sleeve,and filler sleeve onto one of thecoaxial cables in the given order.


4. Shrink the filler sleeve over thesplice. Use reflector, temperature setat 900°F. Keep hot air away from innerand shield sleeves.

5. Shrink the inner sleeve over thesplice, Figure 11-27. Use samereflector and temperature. Keep hotair away from shield sleeve.

6. Center and shrink the shield sleeveover the splice area so that the soldermelts and flows, Figure 11-28. Shieldsleeve braid must overlap coax braid atboth ends. Use same reflector and tem-perature.


11-17. COAX SPLICE FOR RG-9B/U,RG-214/U, RG-225/U, RG-393/U.

GENERAL INFORMATION: There are variouscoax splices in the wiring repair kitthat may be used for the differenttypes and sizes of coax cable.



MATERIALS/TOOLS REQUIRED: Crimp Tool (item 10, Appx B) Coax Splice (item 10, Appx B) Stripper or Knife Reflector (item 10, Appx B) Heat Gun/Heat Source (item 10, Appx B)

11-30



Figure 11-27. Coax Splice Inner Sleeve

Figure 11-28. Coax Splice Shield Sleeve

PROCEDURAL STEPS:


2. Slide the tubing, inner sleeve, andfiller sleeve onto one of the coaxcables in the order given.


4. Shrink the filler sleeve over thesplice. Use reflector, temperature setat 900°F. Keep hot air away from shieldsleeve and tubing.

5. Center and shrink the shield sleeveover the splice area so that the soldermelts and flows, Figure 11-29. Shieldsleeve must overlap coax braid at bothends. Use same reflector and tem-perature. Keep hot air away fromtubing.

6. Center and shrink the tubing overthe splice area. Use reflector withtemperature set at 900°F.


Figure 11-29. Coax Splice withTubing Sleeve

11-18. COAX SPLICE FOR RG-58C/U,RG-233/U, RG-59B/U, AND RG-71B/U.

GENERAL INFORMATION: There are variouscoax splices in the wiring repair kitthat may be used for the differenttypes and sizes of coax cable.

LIMITATIONS: This is a temporary repair.


11-31


MATERIALS/TOOLS REQUIRED: Coax Splice (item 10, Appx B) Stripper or Knife Reflector (item 10, Appx B) Heat Gun (item 10, Appx B)

PROCEDURAL STEPS:

1. Prepare coax cable, Figure 11-26. Figure 11-31. Coax Repair with CableRefer to Table 11-5. Braid over Barrier Sleeve

2. Slide the shield sleeve and fillersleeve onto one of the coax cables inthe order given.

3. Insert center conductors to overlapin center conductor splice. Barriersleeves of center conductor splice fitunder cable braids, Figure 11-30. Heatusing reflector, temperature set at900°F.

4. Shrink the filler sleeve over thesplice. Use same reflector and tem-perature. Keep hot air away fromshield sleeve.

5. Center and shrink the shield sleeveover the splice area so that the soldermelts and flows. Shield sleeve braidmust overlap coax braid at both ends.Refer to Figure 11-31. Use samereflector and temperature.


11-19. COMPONENT BRIDGING.

GENERAL INFORMATION: In most cases, itwill be quicker not to replace bulkheadconnectors, junction boxes, or terminalstrips. These circuits can be repairedby "bridging" the damaged area withjumper wires spliced in to eliminate thedamaged area or component, Figure 11-32.

LIMITATIONS: Will be dependent on thetype of splice used. Typically, tem-porary repair.

PERSONNEL/TIME REQUIRED: Will be dependent on the type of

splice used. Typically 1 soldier,15-30 minutes per splice.

MATERIALS/TOOLS REQUIRED: Will be dependent on the type of

splice used.

1. Identify wires to be bridgedtogether.

2. Splice wires and jumper wirestogether using one of the splicingtechniques of this chapter.

3. Secure jumper wires after repairis made.

4. Record BDAR action taken. Whenmission is complete, as soon aspractical, repair the equipment/system

Figure 11-30. Coax Splice with Cable using standard maintenance procedures.Braid over Barrier Sleeves

11-32

PROCEDURAL STEPS:

Figure 11-32.

11-20. CONNECTOR

Component Bypass

REPAIR.

GENERAL INFORMATION: Deformed, crushed,missing, or otherwise damaged connectorscan be replaced or repaired. If areplacement connector is not availableto replace a crushed connector, clean upfragments of the connector and usejumper wires to bridge wire endstogether. If only part of the connectorhas been damaged and there are unusedpins/sockets on the connector which areundamaged, wires on both sides of theconnectors can be moved to the unusedgood pins/sockets. Also, any availableundamaged pigtails on the connector maybe used.

OPTION 1: Damaged Pins or Sockets; NoDamage to Connector.

LIMITATIONS: None.


MATERIALS/TOOLS REQUIRED: Replacement Pins/Sockets

(item 2, Appx B) Insertion/Extraction Tool

(item 2, Appx B) Knife

PROCEDURAL STEPS:

1. Solder or crimp wires topin/sockets, Figure 11-33.

2. Insert the pins/sockets into theconnector.



Figure 11-33. Connector Pin and Socket

NOTE

Superglue or epoxy may be used tosecure the original or replace-ment pin back into place. Avoidgetting glue or epoxy on contactsurface of pin.

OPTION 2: Bridge Across Partially orFully Damaged Connector.

LIMITATIONS: Temporary repair.


MATERIALS/TOOLS REQUIRED: Wire Splice (item 10, Appx B) Wire (items 61, 62, Appx C)

PROCEDURAL STEPS:

1. Locate the damaged wire ends that gointo connector.

2. Splice the appropriate wirestogether. The splice will bypass theconnector.

11-33



OPTION 3: Cannibalizing Connector fromOther Aircraft.

LIMITATIONS: None.


MATERIALS/TOOLS REQUIRED: Replacement Connector with Pigtail Splices or Tape (item 10, Appx B) Knife

PROCEDURAL STEPS:

1. Obtain a replacement connector witha pigtail. (Replacement may be obtainedfrom a crash damaged aircraft.) Cutpigtail so that splices can be staggered,Figure 11-34.

2. Remove damaged connector; staggerthe wires being cut to remove thedamaged connector. The staggered wiresshould match the staggered pigtail ofthe replacement connector of step 1,Figure 11-34.

3. Splice the appropriate wirestogether. Insulate properly.


Figure 11-34. Damaged Connector and Pigtail

11-34


11-21. CIRCUIT PROTECTION DEVICE REPAIR.

GENERAL INFORMATION: Attempt to main-tain a fused system at all times.Circuits with damage circuit breakerscan be repaired by:

a. Circuit breakers of the samerating salvaged from other non-flyableaircraft, or removed from other non-essential circuits in the aircraft.

b. Replacing circuit breakers with aspecified number of individual strandsof No. 38 AWG wire from No. 26 AWG wire.

OPTION 1: Salvaged Circuit BreakerReplacement.

6. Connect back of circuit breaker toline and bus bar by reinstalling the twophillips screws.

7. Place inside star washer and nut onfront of circuit breaker and tightenwith pliers.

8. Replace plastic face plate on frontof circuit breaker panel with screwspreviously removed.

9. Clean and remove any debris frominside circuit breaker panel and closepanel. Secure by turning duze fastenersclockwise.

OPTION 2: Individual Strands of No. 38AWG as Circuit Breaker BDAR Repair.

LIMITATIONS: None.LIMITATIONS: Emergency repair.


MATERIALS/TOOLS REQUIRED:. Salvaged Circuit Breaker. Electrical Tape (item 49, Appx C)

PROCEDURAL STEPS:

1. Gain access to area behind circuitbreaker panel, Figure 11-35, by turningduze fasteners counterclockwise.

2. Remove screws holding plastic faceplate on circuit breaker panel.

3. Use pliers to remove nut and insidestar lock washer from damaged circuitbreaker.

4. Use phillips screw driver to removethe two screws from the back of thecircuit breaker.

5. Replace bad circuit breaker with thesalvaged circuit breaker.


MATERIALS/TOOLS REQUIRED:. 1 Foot of No. 38 AWG Wire

PROCEDURAL STEPS:

1. Perform steps 1 thru 4 of option 1.

2. Identify the wires hooked to eachcircuit breaker. Typical circuitbreaker is shown in Figure 11-36.

3. Determine amperage of damagedcircuit breaker(s) to be replaced.(Amperage is printed on the end of resetbutton.)

4. Use Table 11-7 to determine numberof strands of No. 38 AWG wire needed toreplace damaged circuit breaker.

5. Select strands of No. 38 AWG wire tobe used. Strands should be 6 to 8inches long.

11-35


Figure 11-35. Circuit Breakers

11-36


No. 38 AWG strands of wire. Insertthe other end of No. 38 AWG strands ofwire into the other terminal lug (supply

Figure 11-36. Typical CircuitBreaker Connection

CIRCUITBREAKERAMPERAGE

1/2A

2A3A4A5A10A15A20A

AWGSIZEWIRE

N0. 38N0. 38N0. 38N0. 38N0. 38N0. 38N0. 38N0. 38N0. 38

NO. OFSTRANDS

111

2257

10

NOTE

Try to use inner strands of wirethat are not cut or nicked byknife used to remove insulation.

6. Remove line side, Figure 11-37, byunscrewing 8-32 screw. Repeat forsupply side.

7. Twist the No. 38 AWG strands ofwire from step 5 together and insertthe end of line side of terminal lug;wrap and twist as shown in Figure 11-37.Slip 1 inch piece of insulation over

side). Pull tight against the piece ofinsulation and twist tight. Insulatebare end of terminal lugs on both sidesof 1 inch piece of insulation with tape.Use 8-32 screw to connect other terminallug to bus side of bus bar.

8. Use this procedure to replacedamaged circuit breaker.

9. Secure fuse link to other wiringwith tape to avoid pinching wire whencircuit breaker panel is closed.

10. Clean up damaged area behindcircuit breaker panel to remove debris,and use tape to insulate any damagedparts that might cause electricalshorts.

11. Carefully close circuit breakerpanel and secure by turning duzefasteners clockwise.


Figure 11-37. Construction of Fuse Link

11-37

Table 11-7. Fuse Link Strands

1A


11-22. BUS BARS.

GENERAL INFORMATION: Rigid bus bars areused in the power distribution circuitsof the aircraft. Replace damaged busbars with copper or brass strips of wireof the same or higher cross-sectionalarea. Use aluminum only when replacingaluminum bus bars since it makesunrealizable contact with other metals.

LIMITATIONS: Repaired bus bars willhave a somewhat higher resistance thanthe original circuit and a higher thannormal voltage drop may occur.Temporary repair.

PERSONNEL/TIME REQUIRED:. 2 Soldiers. 2 Hours

MATERIALS/TOOLS REQUIRED:. Drill and Bit. Nuts, Bolts, Flat Washers, Lock

Washers. Tape (item 49, Appx C). Brush, Wire. File. Hacksaw

PROCEDURAL STEPS:

1. Cut a section of another bus bar touse for splice.

2. Drill matching holes in bus barsections and splice, Figure 11-38.

3. Remove insulation from bus bar onlywhere needed. Insure contact surfacesof cracked bus bar and splice are smooth,and clean to reduce resistance. Ifnecessary, use tile and wire brush todress and prepare contact surfaces.

4. Install bolts and washers andtighten. Insure no contact of boltswith aircraft structure.

5. Insulate repair with tape or slita piece of insulating tubing, and wraparound the repair and tie with string.

6. Samelengthen

repair procedurebus bars, Figure

can be used to11-39.


11-23. BATTERY REPAIR, BB-476/A.

GENERAL INFORMATION: Nickel-Cadmium(Ni-Cad) batteries consist of a numberof cells connected in series. Damage toa cell which does not result in shortcircuiting and destroying the battery.The following procedure gives instruc-tions for locating and removing badNi-Cad battery cells and creating ajumper around the bad cell.

WARNING

. Ni-Cad batteries use potassiumhydroxide, a strong caustic alkali,as the electrolyte. Do not getthis electrolyte on your skin orin your eyes. Use rubber gloves,rubber apron, and protectivegoggles when handling the elec-trolyte. If accidental contactwith the electrolyte is made, useONLY clean water and immediately(seconds count) flush contami-nated areas. Continue flushingwith large quantities of cleanwater and get medical attentionas soon as possible.

. If steam or spewing electrolyteis observed or the battery is hotto the touch, DO NOT ATTEMPT TOremove from the aircraft imme-diately.

CAUTION

Penetration of battery case bysmall arms fire or shrapnel willcause thermal runaway. Thebattery cells will overheat andrupture, melt, or explode.Exercise extreme caution whenrepairing the battery.

11-38


Figure 11-39. Lengthening Bus Bars

11-39

Figure 11-38. Splicing Bus Bars


LIMITATIONS: Some loss of batteryvoltage (1.25 to 1.50 V dc per cellremoved) and amperage capacity.


MATERIALS/TOOLS REQUIRED:. 1 Multimeter with Leads

(item 9, Appx B). Rubber Gloves. Protective Goggles. Rubber Apron. Torque Wrench. One Foot No. 4 AWG Wire or

Equivalent

PROCEDURAL STEPS:

1. Disconnect battery and remove fromaircraft if necessary.

2. Release snap fasteners and removecover.

3. Use a multimeter to measure voltageacross each cell. Normal readingsshould be 1.25 to 1.5 V dc per cell.Remove cells that are dead. For enginecranking loads, cell voltages as low as0.6 V dc are acceptable. Also, removeany damaged, cracked, or extremely hotcells leaking or spewing electrolyte.

WARNING

Be extremely careful whenremoving or installing batterycells. Bodily injury and equip-ment damage may result if anymetal tools or parts accidentallycause a short circuit.

4. To remove bad cells, use a 3/8 inchsocket or equivalent to loosen andremove terminal screws. Remove washersand terminal links. To remove indivi-dual cells, screw terminal screws backinto each cell terminal, grasp thesescrews with pliers and lift the cellstraight up.

5. After removing bad cells, preparejumper from 1 foot of No. 4 AWG and twoterminal lugs. Remove 1/2 inch of insu-lation from one end of wire and crimpterminal lug on stripped end of wire.Measure and cut wire to needed length,strip 1/2 inch of insulation, and crimpterminal lug to other end of wire.

6. Install jumper across removed cellsin place of terminal links. Cells areconnected in series (positive tonegative), Figure 11-40.

7. Torque terminal screws to between 35and 50 inch-pounds. If torque wrench isnot available, tighten firmly withwrench or pliers.

8. Replace cover and install battery inaircraft.

Figure 11-40. Battery, StorageBB-476/A, Cell Layout

11-40

TM 55-1520-228-BD

11-24. DAMAGED OR DEFECTIVE POWER RELAYS.

GENERAL INFORMATION: A power relay isan electrically operated switch betweenthe main bus and other electrical com-ponents in the aircraft. The relays arenormally controlled by a switch in thecockpit. Damage incurred to powerrelays may be temporarily fixed by oneof two options.

a. First option: Replace with goodrelay salvaged from non-flyable aircraftor a nonessential circuit.

b. Second option: Jumper acrosspower terminal and bus bar terminalstuds located on relay case. To checkpower relay for malfunction, locate ter-minals X1 and X2 on the relay. With amultimeter set on the 0-50 V dc scale,check the voltage from terminals Xl andX2 to the aircraft fuselage (ground),Figure 11-41. One of the two terminalsshould have 24-28 V dc on it when thepower relay control circuit isenergized. No dc voltage indicates


damage to the control circuit wiring.Repair control circuit wiring. With24-28 V dc applied to terminals X1 orX2 of the power relay, check the voltagebetween terminals A1, A2, and theaircraft fuselage (ground), Figure11-41. The voltage on terminals A1 andA2 should be identical. If there is novoltage on either one of the two ter-minals A1 or A2 with the relayenergized, the relay should be considereddefective and replaced.

OPTION 1: Salvaged Power RelayReplacement.

NOTE

Identical part number (Figures11-42) denotes interchangeability.If damage is extensive, salvagedrelays may be difficult to attachto bulkheads.

Figure 11-41. Block Diagram Power Relay, Check and Test

11-41


LIMITATIONS: None.


MATERIALS/TOOLS REQUIRED:. Salvaged Power Relay

PROCEDURAL STEPS:

1. Obtain salvaged power relay.

LIMITATIONS: Emergency repair. Nocontrol over jumpered power relays,circuit cannot be turned on or off.


MATERIALS/TOOLS REQUIRED:. Appropriate Size Aircraft Type Wire. Appropriate Size Terminal Lugs

PROCEDURAL STEPS:2. Disconnect battery.

1. Disconnect battery.3. Remove damaged power relay asfollows:

NOTE

Note the position of wires/bus barand what terminals they are con-nected to.

a. Remove attaching hardware, wires,and bus bar.

b. Remove attachment bolt, and liftrelay free from compartment.

4. Position salvaged power relay, andinstall mounting hardware.

5. Install wires and bus bar on correctterminals, and secure with hardware.


OPTION 2: Creating a Jumper for DamagedPower Relays.

CAUTION

. Do not jumper battery relay onan aircraft.

. This procedure is to be usedonly for one time emergencyevacuation and recovery ofOH-58 A/C.

2. Figure 11-43, Type A and B, showstwo typical power relay configurationswith jumper. This may be used as an aidin performing steps 3 thru 7.

NOTE

Use wire with the same gage orlarger than the one being replaced.

3. Prepare a jumper wire, Figure 11-44.(A 1/2 to 1 foot length of appropriatesize aircraft wire with appropriate sizeterminal lugs crimped on each end.)

4. Locate terminals marked A1 and A2on power relay. Power relay terminalsshould be marked on case of relay. Ifmarkings are illegible, A1 and A2 ter-minals will be the ones with the largestdiameter terminal studs.

5. Remove hardware from terminals A1and A2.

6. Install jumper from terminal A1 toterminal A2. Reference Figure 11-45,Type A and B.

7. Install hardware on terminals A1 andA2. Tighten hardware to hold jumper inplace.

8. Remove jumper as soon as emergencyevacuation flight is completed.

11-42


DRAWING PARTDESIGNATION NUMBER FUNCTION

K6 MS24183D1 Relay, BATTERYK1 MS24183D1 Relay, External PwrK11 3S2791G200F-9 Relay, Gen FailK12 MS24183D1 Relay, Line ContK3 MS24183D1 Relay, Non-Ess BusBT1 BB-4761A Battery

Figure 11-42. Location of Power Relays

11-43


TYPE A TYPE B

Figure 11-43. Block Diagram, Typical Power Relays

Figure 11-44. Jumper Wire Fabrication


11-25. SUBSTITUTE EMERGENCY ANTENNA,FIELD EXPEDIENT. This section containsexpedient repair procedures to restoreradio communication needed to completethe mission.

GENERAL INFORMATION: These proceduresgive instructions for use of substituteand/or construction of replacement anten-nas that can be used to transmit andreceive radio messages.

WARNING

Do not touch bare wires on expe-dient antennas with the radiokeyed. You could get burnedand/or shocked.

OPTION 1: Use of Substitute Antennas.

LIMITATIONS: Some loss of antenna gainand radio transmitter power.


11-44

MATERIALS/TOOLS REQUIRED: None

PROCEDURAL STEPS:

1. Be sure that FM No. 1 (1 AN/ARC-114)circuit breaker and BAT switches on theoverhead console are off.

2. Remove vent screen from left side ofhorizontal console to obtain access toNo. 1 FM radio connectors.

CAUTION

Do not pull on cables when dis-connecting cable connectors.Be careful to avoid any unneces-sary strain on the cables.

NOTE

If No. 2 FM radio and secure-voice control indicator arenot installed, blank panelsmay be removed to obtainadditional access to con-nectors.

3. Disconnect cable connectors from J1,J2, J3, and J4.

4. With a screwdriver, turn the sixfasteners that secure the unit to themounting panel one-quarter turncounterclockwise.

5. Slide the No. 1 FM radio out of themounting panel.

6. Locate coax cable (2 ARC 114-101A)stored in console and use it to replacecoax cable (1 ARC 114-101A). Connect itto J2.

NOTE

Both left and right-hand homingantennas may also be used asemergency transmitting anten-nas by using either coax cable(1 ARC 114-102A) or (1 ARC 114-103A) connected to J2.


7. To replace No. 1 FM radio, be surethat FM 1 circuit breaker and BATswitches on the overhead console areoff.

8. Slide the No. 1 FM radio into themounting panel and turn the six faste-ners one-quarter turn clockwise tosecure the unit.

9. Connect the coax cables to the rearof the No. 1 FM radio.

10. Attach vent screen to left side ofhorizontal console.

NOTE

The above procedures apply to theNo. 1 FM radio and to the No. 2FM radio when it is installed,except that J3 and J4 are notused on the second radio.

OPTION 2: Construction of ReplacementAntenna.

LIMITATIONS: Some loss of antenna gainand radio transmitter power.

PERSONNEL/TIME REQUIRED:. 1 Soldier. 1 Hour

MATERIALS/TOOLS REQUIRED:. Cable, Coax RG-58U or Other Available

Coax. Tape, Electrical (item 46, Appx C)

or Equivalent. Resistor, Carbon, 1 Watt 52 ±5

percent.

PROCEDURAL STEPS:

1. Determine length of wire needed forthe rad11-45.

iating element by using FigureExample:

11-45


Frequency Wavelength

Figure 11-45. Frequency vs. Wave Length

TO CHANGE MULTIPLY BYCentimeters . . Inches. . . . . . 0.394Meters. . . . . Feet. . . . . . . 3.280

11-46

● FM radio with frequency range of 30 to69.95 MHZ.

● Center of frequency range is 50 MHZ.

● Using Figure 11-45, look under frequencycolumn for 50 MHZ on the wave lengthside of the Table, 6 M is shown.

● Use Figure 11-45 to convert meters tofeet. Six meters multiplied by 3.280= 19.68 feet for one wave length.

● Divide the one wave length by 8, for a1/8 wave length antenna, 19.68 = 2.46

feet. Multiply the 1/8 wave length bya .95 correction factor: 2.46 ft. X.95 = 2.34 feet. This is the lengthof the radiating element.

2. Cut the coax cable to the length ofthe required radiating element. Removethe outer insulation and shield from thepiece of coax cable and then strip a 1inch piece of insulation from each endexposing the center conductor, Figure11-46A.

3. Wrap and solder the 52 resistor toone end of the radiating element as perFigure 11-46B. This completes the fabri-cation of the radiating element of theantenna.

4. Next, remove the structural panel onthe right-hand side just forward of thetail boom, Figure 11-47, by removingtwenty-seven screws.

5. At the tail boom quick disconnect,locate coax cable marked 1 ARC 114-101Band disconnect it. Remove the coax con-nector and prepare a 4 inch pigtail ter-mination on the end of the coax cable asshown in Figure 11-46C.

6. Stick the radiating element of theantenna from step three with the resis-tor end down into the drain hole in thebottom of the tail boom where it joins thefuselage, Figure 11-47.


Figure 11-45. Preparation of Coax11-47


7. Twist the center conductor from theradiating element of the antenna to thecenter conductor of the coax. Make agood mechanical joint and insulate withtape.

8. Ground the pigtail from the coaxantenna by wrapping and twisting itaround the plug where the coax wasdisconnected.

9. Secure with tape to hold theantenna and coax in place inside the

tail boom. Replace the structural paneland secure with screws.

NOTE

Antenna must be at right angle(90°) to aircraft skin to radiateR.F. energy. Do not tape antennato skin of aircraft.

10. Using tape, tape a one to two ounceweight below the 52 resistor as shownin Figure 11-47.

11-48


Figure 11-47. Installation of Field Expedient Antenna

11-49/(11-50 Blank)

TM 55-1520-228-BD

CHAPTER 12

FUEL SYSTEM




Section I.

12-1. GENERAL.

a. The fuel supply system, Figure12-1, consists of a crashworthy bladdertype, self-sealing cell. The fuel cellis designed to fit under the passengerseat, in the floor cavity of the fuse-lage. The system’s fuel flow lines areself-sealing. The rigid lines are usedfor fuel flow or as vent lines. Thefuel boost pump is the cartridge typewhich can be replaced without defueling.

b. The fuel tank will self-seal whendamaged by small arms projectiles up to50 caliber. Damage to the tank and the

Section II.

12-4. GENERAL.

a. Replacement lines and hoses neednot be routed along the path of the ori-ginal installation. They may be routedalong any convenient path as long asthey do not interfere with personnel orwith operating equipment. Long linesand hoses should be clamped to hard sup-ports at convenient intervals notexceeding 24 inches.

b. Tubing in the OH-58 fuel system islimited to the fuel vent line. Whendamage occurs to any of the lines (tubesor hoses), they may be substituted witha flexible type hose from the kit.

c. If hose assemblies from the kitare not available, damage may be cut outand replaced with a small section (referto repair procedures), or a replacement

INTRODUCTION

fuel system must be evaluated very care-fully to determine damage which requiresimmediate repair and that which does notconstitute a flight hazard.



PARA.

Hose and Line Replacement. . . 9-7O-Ring Damage. . . . . . . . . 9-10Fuel Substitution. . . . . . . 12-6Fuel Cell Repair . . . . . . . 12-7

LINES AND HOSES

hose may be manufactured if a longenough hose section and MS fittings areavailable (refer to repair procedures).

d. Never discard MS fittings, theyare reusable. The MS21922 sleeve is notreusable.

12-5. O-RING DAMAGE. Refer to Chapter9, paragraph 9-10. The same criteriathat applies to hydraulic o-rings alsoapplies to o-rings in the fuel system.

12-6. FUEL SUBSTITUTIONS.

a. If the standard fuel is not avail-able, a substitute fuel must be used.Check Appendix D for a compatible fuel.

b. Record BDAR action taken. Whenmission is complete, as soon aspractical, repair the equipment/systemusing standard maintenance procedures.

12-1

TM 55-1520-228-BDFUEL SYSTEMS

RECEIVER

NOTE

RECEIVER REPLACES CAP AND ADAPTER ON HELICOPTERSEQUIPPED WITH CLOSED CIRCUIT REFUELING PROVISIONS.

1. Cover Assembly2. Low Level Switch3. Lower Transmitter4. Fuel Pump5. Fuel Shut-Off Valve6. Fuel Shut-Off Cable7. Fuel Shut-Off Lever8. Auxiliary Fuel

Cell Fitting

Figure 12-1. OH-58 Fuel System

12-2


Table 12-1. Fuel System Assessment Procedures

12-3


Section III. FUEL CELL DAMAGE

12-7. FUEL CELL DAMAGE.

GENERAL INFORMATION: The fuel cellsrestrict the catastrophic loss of fuelin survivable crashes. The repairs spe-cified in this section, however, willnot necessarily return the cells totheir original crash resistant level.Fuel cell damage can be categorized asfollows:

a. Nonrepairable:

(1) Damage to metal plate of fit-tings on tank which causes leakage.

(2) Damage to tank wall whichexceeds 3 inches.

(3) Damage within 2 inches ofmetal fitting.

b. One-Time or Emergency FlightCapability Repair:

Mechanical Clamp Repair (option 1).

c. 100 Flight Hour Capability Repair:

(1) Adhesive repair (option 2).

(2) Flat panel repair, one plane(option 3).

(3) Two plane repair (option 4).

(4) Three plane repair (option 5).

OPTION 1: Mechanical Clamp Repair.

LIMITATIONS: Emergency flight repair.

PERSONNEL/TIME REQUIRED:. 1 Soldier. 30 minutes

MATERIALS/TOOLS REQUIRED:. Mechanical Repair Sealing Clamp

(3 or 5 inch). Knife

PROCEDURAL STEPS:

1. Defuel the fuel cell by thefollowing procedure:

a. Remove the fuel drain cover panel.

b. Push or twist drain valve locatedunder aircraft where fuel pump is located.

c. Place a bucket or any type recep-tacle under the aircraft to catch thefuel.

2. Locate the damage (e.g., hole ortear) on the cell.

NOTE

For holes less than 2 inches across,use the 3 inch clamp. For holesgreater than 2 inches across butless than 3 inches across, usethe 5 inch clamp. Holes largerthan 3 inches are nonrepairable.

3. Use the knife to enlarge the hole to3/4 inch to 2 inches maximum for a 3inch clamp and 1 inch to 3 inch maximumfor the 5 inch clamp.

4. Insert the bottom plate of the clampthrough the hole and pull up using thecord. Position the plate so the hole isentirely within the gasket area. Slipthe top plate over the threaded stud andhand tighten the wing nut, Figure 12-2.

CAUTION

Excessive mechanical tighteningof the wing nut can result infailure of the clamp. The wingnut shall be finger tightened,and the maximum torque on thewing nut shall not exceed 10 to12 inch-pounds.

5. Tighten drain valve and installcover plate.

12-4


Figure 12-2. Emergency Mechanical Clamp Repair

12-5


6. Refuel the aircraft. CAUTION


OPTION 2: Adhesive Repair.

LIMITATIONS: Temporary repair, 100flight hour capability. Inspect afterevery flight.


MATERIALS/TOOLS REQUIRED:. Knife. Solvent, 1-1-1 Trichloroethane or

Equivalent (item 59, Appx C). Repair Fabric. Abrasive Cloth (item 1, Appx C). Adhesive (item 3, Appx C). Plastic Container/Cup. Wooden Tongue Depressor (item 60,

Appx C)

PROCEDURAL STEPS:

1. Defuel the aircraft. Refer tooption 1, step 1.

2. Once step 1 (above) has beencompleted, locate the damage. Trim onlythe outer exposed damage area to providea reasonably smooth exterior surface.DO NOT ENLARGE HOLE.

3. Abrade and solvent wash the areasurrounding the damage. Clean at least4 inches beyond the damage.

4. Cut a fabric patch to overlap thedamaged area by a minimum of 1 inch allthe way around. Soak the patch insolvent. (NOTE: No hole is required inthe center of the patch.)

5. Mix the adhesive as described belowin steps 5a thru 5h, refer to Figure12-3.

Wear goggles or other eye protec-tion during all operations.

a. Remove the tape band from Semkitcartridge and pull the mixing rodstraight up toward the top of thecartridge.

b. Squeeze cartridge slightly in areaof the removed tape band to deform foilbarrier.

c. To mix dry filler to base com-pound, push mixing rod to bottom ofcartridge and begin stroking in spiralclockwise motion from top to bottom ofcartridge, rotating mixing rod approxi-mately 90° with each stroke. Mix forthe total number of strokes indicated onthe instruction card accompanying eachSemkit (40 strokes). A stroke is onecomplete in and out cycle. On laststroke, mixing rod should be fullyextended.

d. Pull mixing rod out approximatelyone-third of way.

e. Insert ram rod into hole in top ofmixing rod and inject about one-third ofcuring agent into the cartridge.

CAUTION

Use firm but even pressure. Donot force, tap, or jolt ram rod.

f. Repeat steps a and b until all ofthe contents of the rod are emptied intothe cartridge.

g. Mix curing agent into cartridge byrepeating step c.

h. Grasp cartridge firmly at neck andunscrew mixing rod by turning counter-clockwise approximately three turns.Remove mixing rod and discard.

12-6


Figure 12-3. Mixing Instruction for Sealant Cartridges

6. Apply adhesive to the wound openingfor a least 1-1/2 inches around thedamaged area or enough to accept thepatch cut in step 4 (above).

7. Apply and smooth out in the appliedadhesive a solvent soaked fabric patch tothe damaged area. Apply adhesive ifrequired to seal the patch to the tank,and smooth out the surface.

CAUTION

The patch will tend to slip whenapplying additional adhesive andsmoothing. Be sure to recenterthe patch.

8. Maintain the patch position untilthe adhesive sufficiently sets (approx.30 min). (NOTE: Allow the adhesive tocure for two hours before refueling.)


10. Refuel the aircraft.

11. Record BDAR action taken. When .mission is complete, as soon aspractical, repair the equipment/systemusing standard maintenance procedures.

OPTION 3: Flat Panel Repair (One Plane).

LIMITATIONS: Inspect after every flight.


MATERIALS/TOOLS REQUIRED:. Knife or Scissors. Solvent, 1-1-1 Trichloroethane or

Equivalent (item 59, Appx C). Abrasive Cloth (item 1, Appx C). Repair Fabric. Adhesive (item 3. Appx C). Plastic Cup or Other Small Container. Rubber Plug Kit

PROCEDURAL STEPS:

1. Defuel the aircraft. Refer tooption 1, step 1.

12-7


2. Once step 1 of this section has beencompleted, locate the damage; enlarge thewound in the tank to no more than 3inches in diameter by using a knife orscissors. Remove all frayed fabric anddamaged inner lines.

3. Abrade the inner lines or innersurface at least 1/2 inch beyond theenlarged hole, preferably more if con-ditions permit. Abrade the outer sur-face to a minimum of 4 inches from theenlarged area. (NOTE: If the frayingfibers are too numerous, trim the fiberwith scissors.)

4. Clean the abraded areas using towelssoaked in solvent.

5. Cut a fabric patch 4 inches indiameter or large enough to extend atleast 1 inch beyond the damaged area andadd a 1/2 inch hole in the center. Soakthe patch in solvent.

6. Mix the adhesive per option 2instructions, step 5, and extrude into aplastic cup. (NOTE: Adhesive can beused between 20° through -120°, but mustbe warmed to room temperature prior tomixing and be mixed at room temperature.Pot life of adhesive is approximately 25minutes at 70°F.)

7. Apply adhesive to inner liner usingfinger to swab cement around the wound.Apply adhesive to concave surface of therubber plug (this is the surface thecord is attached to). Refer to Figure12-4 for rubber plug assembly.

NOTE

Use adhesive as required, retainsome for finishing the outside ofthe cell repair.

8. Fold the rubber plug and insert itthrough the hole in the cell. (NOTE: Retain cord to prevent loss of plug inthe cell.)

9. Pull the plug into position androtate it in position to smooth out theadhesive interface. Center the plug onthe wound.

10. Apply a layer of adhesive 4 inchesin diameter around the wound on the out-side and fill in the wound with adhe-sive. (NOTE: There must be a minimumof a 1/2 inch bond.)

11. Apply the solvent soaked fabricpatch to the outside surface by passingthe cord through the hole in the patchand position the patch over the wound.Smooth the patch into the adhesive.

12. Pull the cord and tape to thestructure keeping a slight tension.

13. Do not disturb the repair for aminimum of 30 minutes, and let cure twohours before refueling. Cut the stringand plug stem without disturbing therepair.


15. Refuel the aircraft.


OPTION 4. Two Plane Repair. Damage toa two plane area will be repaired in thesame manner described in option 3,except the hole should not be enlargedto more than 1/2 X 2-1/2 inches.

OPTION 5. Three Plane Repair. Damageto a three plane area will be repairedin the same manner as described inoption 3, except the hole should not beenlarged to more than 1/2 X 2-1/2 inchesand the rubber plug will be cut as shownin Figure 12-5. This will allow theplug to assume the contour of the tankwhen pulled into place.

12-8


Figure 12-4. Rubber Repair Plug Assembly

Figure 12-5. Plug Modification for Three Plane Repair

12-9/(12-10 Blank)

TM 55-1520-228-BD

CHAPTER 13

FLIGHT CONTROLS





13-1. GENERAL. and tail rotor controls to the aftflight control components. Refer to

a. The flight control system is made Figure 13-1 for a schematic of theup of the main rotor collective controls, system.cyclic controls, and the tail rotor con-trols. The tail rotor pedals are con- 13-2. ASSESSMENT PROCEDURES. Refer tonected to the tail rotor assembly. Table 13-1.

b. This chapter contains some BDAR 13-3. REPAIR PROCEDURE INDEX.procedures which may be used toaccomplish repairs to the flight controltubes. Flight control tubes connect thecopilot’s and pilot’s cyclic, collective, Tubes,

Section II. TUBES, FLIGHT

13-4. SUBSYSTEMS AND ASSEMBLIES. Thereare various subsystems and assemblieswithin the flight control system thatare vital for combat aircraft maneuvera-bility and control but are not neces-sarily essential for basic flight capa-bilities. Refer to Table 13-1 forassessment procedures.

a. Force Trim System. If the forcetrim system is malfunctioning, theaircraft is still fully mission capablewith no limitations presented.

b. Control Rods.

(1) Copilot to Pilot. If anycontrol rods, bell-cranks, or linkagesconnecting the copilot controls to thepilot controls break or otherwise becomeinoperable, the pilot may assume fullcontrol for the particular functionwhich has been damaged, provided thatthe damaged part does not become jammedin the surrounding aircraft structure.

Once the

PARA.

Flight Control. . . . 13-5

CONTROL

aircraft is on the ground, ifno replacement parts are available, thecontrol tube may be splice-repaired(refer to paragraph 13-4) or removed toavoid any possibility of the controltube getting jammed. If the tube isremoved, the pilot assumes full controlof the function that has been lost tothe copilot.

(2) If any flight control systems,including control rods, bell-cranks,linkages, hydraulic cylinders, etc.,which lie between the pilot and the mainrotor blade or tail rotor blade sustaindamage during flight, the aircraft willbe uncontrollable and forced to crashland.

13-5. TUBES, FLIGHT CONTROL.

GENERAL INFORMATION: The followingrepair procedures may be used toaccomplish repairs to flight controltubes. Flight control tubes connect the

13-1

Figure 13-1. OH-58 Flight Controls Schematic

13-2

TM 55-1520-228-BDFLIGHT CONTROLS SYSTEM


Table 13-1. Flight Control System Assessment Procedures

13-3


copilot’s and pilot’s cyclic, collec-tive, and tail rotor controls to the aftflight control components. See Figure13-1 for a schematic of the system, andrefer to Figures 13-2 thru 13-5 for acomplete detail on each individualsystem and Figure 13-6, Table 13-2, fordimensions of tubes. Make all necessaryrepairs on all flight control tubesusing one of the two options provided inthis section. Insure that splicerepairs, option 1, do not cause anyinterference at bulkhead lighting holesor adjacent components.

OPTION 1: Splicing, Tubes, FlightControl.

LIMITATIONS: Inspect after everyflight.

PERSONNEL/TIME REQUIRED: 1 Soldier 2 Hours

MATERIALS/TOOLS REQUIRED: Metal Sleeve Angle Stock Bolts

PROCEDURAL STEPS:

1. Put aircraft flight control systeminto neutral rig.

2. Disconnect and remove damagedcontrol tube from aircraft.

3. Trim damaged area.

4. Using Table 13-2 and Figures 13-2thru 13-5, select a metal splice,either inner or outer whichever is moresuitable, and drill at least twobolt/rivet holes on each end of thetube. Refer to Table 13-3 forbolt/drill sizes to use on differentsize tubes. Holes should go through thesplicer and the damaged tube, and shouldbe positioned in a cross pattern, Figure13-7. Make sure that the originalcenter to center, length b, Figure 13-6,is maintained.

5. Reinstall tube after repair isaccomplished, and check for binding orinterference by manually moving theappropriate controls: cyclic, collec-tive, or pedals.


OPTION 2: Fabricating, Tubes, FlightControl.

LIMITATIONS: Inspect after every flight.


MATERIALS/TOOLS REQUIRED: Tube Stock (about same dia. as original

tube, 0.032 in. min. wall thickness) Drill and Bit

PROCEDURAL STEPS:

1. Put aircraft flight control systeminto neutral rig.

2. Remove damaged flight control tube,Figure 13-8.

3. On the end that fits into the clevisbolt, mash the tube so that it fits intothe arms of the clevis. A small amountof clearance between the clevis armsshould be allowed, Figure 13-9. Roundoff the end of the mashed tube, Figure13-10. Drill a hole through the tubeand install the bolt.

4. On the end where the clevis boltwould normally fit, mash the tube onlyenough to fit over the bearing assemblywith some clearance. Round off the endof the tube, Figure 13-11.

13-4


Figure 13-2. Collective Flight Control13-5


Figure 13-3. Cyclic Flight Control

13-6


Figure 13-4. Flight Control Actuators 13-7


13-8

NOTE

THIS IS A CONFIGURATION OF THE OH-58ASERIES HELlCOPTER.

Figure 13-5. Anti-Torque Controls (Sheet 1 of 2)


NOTE

THIS IS A CONFIGURATION OF THE OH-58CSERIES HELlCOPTER.

Figure 13-5. Anti-Torque Controls (Sheet 2 of 2) 13-9


(Refer to Figures 13-2 thru 13-5)

Figure 13-6. Control Tube Dimensions

Figure 13-7. Suggested Repair for Control Rods or Tubes

13-10


Table 13-2. Nominal Tube Splice Sizes

NO.1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

FIG13-2

13-2

13-3

13-3

13-4

13-4

13-4

13-4

13-5

13-5

13-5

13-5

13-5

13-5

13-5

NOTE: ALL DIMENSIONS

NSN1680-00-125-8871

3040-01-010-6779

3040-00-179-6880

3040-01-012-5969

3040-01-017-7587

3040-01-007-5514

3040-01-018-9710

3040-00-483-8616

3040-00-024-4146

3040-00-129-6163

3040-00-129-6137

3040-00-129-6142

3040-01-006-4907

3040-00-129-6135

PARTNUMBER

206-001-174-3

206-001-096-7

206-001-306-11

206-001-096-1

206-001-194-5

206-001 -194-1

206-001 -099-1

206-001-189-5

206-001-020-67

206-001-020-69

206-001-020-59

206-001-020-29

206-001-020-33

206-001-096-25

206-001-021-13

1

1 3/8

2

1 3/8

3/4

3/4

3/4

5/8

5/8

1 1/8

1 1/8

1

7/8

7/8

15/16

1 15/16

9/16

9/16

1 1/16

1 1/16

15/16

13/16

13/16

WALL.065

.049

-

.035

.035

.035

.035

.035

-

.035

22

41.9

19.7

46.1

6.5

7.2

9.1

5.25

11.2

9.5

45.4

46.6

38.8

51.4

167.3

Table 13-3. Recommended Bolts and Drill HoleSizes for Splice Repair

LINK NOMINAL MINIMUM BOLT SIZE MAXIMUM BOLT SIZEO.D. FOR BOLT DRILL HOLE FOR BOLT DRILL HOLE5/8 No. 6 5/32 No. 8 3/16

3/4 8 3/16 10 7/32

7/8 10 7/32 1/4 9/32

1 10 7/32 1/4 9/32

1/8 10 7/32 1/4 9/32

1-1/4 1/4 9/32 5/16 11/32

1-3/8 1/4 9/32 5/16 11/32

1-1/2 5/16 11/32 3/8 13/32

25.2

48.4

10.5

11.4

13.9

10.25

12.65

11.0

46.8

48.0

40.2

168.65

13-11

ARE IN INCHES

SIZEO.D. I.D. b

-

- -

-

-

- -

- -

- -

-

- -

-

aLENGTH (IN)

Figure 13-8. Control Rod with Bearing and Clevis Assemblies

13-12



Figure 13-9. Flattened End of Fabricated Flight Control

Figure 13-10. Corner Rounding on Fabricated Flight Control

Figure 13-11. Bearing Assembly Connection of Fabricated Flight Control

13-13


5. From Table 13-2, determine the 6. Record BDAR action taken. Whencorrect distance between holes of the mission is complete, as soon asflight tube. Mark this distance. Drill practical, repair the equipment/systemthe hole and install the bolt. using standard maintenance procedures.

13-14

TM 55-1520-228-BD

CHAPTER 14

UTILITY SYSTEM





14-1. SCOPE. 14-2. ASSESSMENT PROCEDURES. Visuallyinspect the damaged de-icing components

a. The de-icing system is the means to determine the extent of damage andby which the engine is kept from an the repair required.icing condition. The system consistsof a de-ice switch and a de-ice control 14-3. REPAIR PROCEDURE INDEX.actuator protected by a 5 amp circuitbreaker. Refer to Figure 14-1. PARA.

b. This chapter consists of two BDAR De-Ice Valve or Controlfixes which can be applied for repair of Repair. . . . . . . . . . 14-4the de-icing system components.

Section II. DE-ICE VALVE OR CONTROL

14-4. GENERAL INFORMATION: Damage tocontrol rod may be repaired by using oneof the following repair options.

OPTION 1: Splice Repair.

LIMITATIONS: None.


MATERIALS/TOOLS REQUIRED: Flat or Round Piece of Material

(Example: engine cowl hold open rod) Drill with Bit No. 8 screws or bolts

PROCEDURAL STEPS:

1. Drill hole on end of control rod.Insure that original length of damagedrod is known. Cut substitute tube toproper length and drill hole on otherend. Install substitute tube and securewith screw or bolts and nuts.


OPTION 2: Manual Control of Valve.


MATERIALS/TOOLS REQUIRED: 0.041 or O.032 Safety Wire

PROCEDURAL STEPS:

1. Remove damaged control rod from de-icevalve and control actuator. If extremelycold weather, secure de-ice valve controllever in open position by tying the leverto an adjacent part of the engine nosearea. If hot weather, secure valve inclosed position with safety wire.


14-1

TM 55-1520-228-BDUTILITY SYSTEMS

Figure 14-1. Engine De-Ice System

14-2

TM 55-1520-228-BD

CHAPTER 15

ENVIRONMENTAL CONTROL SYSTEM





15-1. SCOPE. This chapter containsBDAR procedures for the heat and vent,bleed air, and defogging systems. TheOH-58A/C has one of three types of heatsystems: bleed air, Figures 15-1 thru15-3; combustion heater, Figure 15-4;or shroud heater system, Figure 15-5.

15-2. GENERAL.

a. The three systems consists of airmixing valve, air distribution ducts,defroster nozzles, and control switchesto operate system.

c. The shroud heater system utilizesa carbon monoxide (CO) indicator locatedat the instrument panel in full view ofthe pilot.

WARNING

If CO indicator is noted to bedark, turn off heater, pull fire-wall shut-off open vents, andland as soon as practicable.


b. The heat and vent system is pro- 15-4. REPAIR PROCEDURE INDEX.vided for crew comfort. This aids themission proficiency; however, the air- PARA.craft capability is not contingent onsystem operation. The aircraft is fully Rigid Plastic Ducts. . . . . . 15-5flight capable without the system being Flexible Ducts . . . . . . . . 15-6operable. Bleed Air Lines. . . . . . . . 15-7

Section II. RIGID PLASTIC VENTILATION DUCT

15-5. GENERAL INFORMATION: Some damage PERSONNEL/TIME REQUIRED:to plastic ducts is repairable provided 1 Soldierthe time required to gain access to the 1 Hourdamaged duct is feasible.

MATERIALS/TOOLS REQUIRED:OPTION 1: Hole or Crack in Duct, Rigid Sheet Metal Patch, 0.016 inchPlastic. Thickness Minimum

Tape, Army Green or AluminumLIMITATIONS: Inspect after every flight. (item 50, Appx C)

15-1

TM 55-1520-228-BDENVIRONMENTAL CONTROL SYSTEM

Figure 15-1. Bleed Air Heating and Ventilating System A & C

15-2


2.3.4.5.6.7.8.9.

10.

Vent and Defog ControlHeat ControlHeat Control CableBleed Air TubeMixing ValvePlenumRemote SensorFresh Air InletPost PlenumAir Distribution Valves

11.12.13.14.15.16.17.18.

20.

Windshield Defog NozzlePlenum DrainPlenum Valve AssemblyVentilating and Defogging BlowerRam Air Intake GrillAir Distribution VentsCouplingClampNoise FilterTube

Figure 15-2. Heating and Ventilating System (Bleed Air) A Model

15-3

1.

19.


1. Vent Control2. Heat Control3. Heat Control Cable4. Bleed Air Tube5. Mixing Valve6. Plenum7. Remote Sensor8. Fresh Air Inlet9. Center Post Duct10. Air Distribution11. Windshield Defog Nozzle

12.13.14.15.16.

17.18.19.20.21.

Plenum DrainPlenum Valve AssemblyVentilating and Defogging BlowerRam Air Intake GrillAir Distribution ValvesCargo/Passenger AreaCouplingClampNoise FilterBlower Inlet DuctTee Valve

Figure 15-3. Heating and Ventilating System (Bleed Air) C Model

15-4


2.3.4.5.6.7.8.9.

10.11.12.13.14.

Combustion Heater PlenumFuel Shut-Off ValveFuel PumpFuel Pressure Relief ValveFuel FilterHeaterCombustion BlowerAir ScoopIgniter PlugDuctFirewall Shut-Off ControlTemperature ControlPilot Seat BackCopilot Seat Back

Figure 15-4. Combustion Heater

15-5

1.


2.3.4.5.

15-6

Blower 6.Air Mixing Valve

7.Firewall Shut-Off Valve 8.Air Mixing Valve Control 9.Firewall Shut-Off Valve 10.Control 11.

Defogger Distribution ValvesCockpit Distribution ValvesCabin Distribution ValvesFan Air IntakeCold Air IntakeShroud Assembly

Figure 15-5. Shroud Heater System Schematic

1.


Table 15-1. Assessment Procedures

15-7


PROCEDURAL STEPS: 3. Stop drill any cracks which might beextending from hole.

1. Locate damaged area and removepanels and/or other items as necessary Sand both the bottom surface of theto gain access to the duct to be patch and the surface area around therepaired. Refer to Figures 15-2 and hole to be covered by the patch.15-3 for locations of rigid plasticducts. 5. Clean surface with solvent.

2. Cut a patch out of sheet stock. 6. Apply sealant to patch and on thesurface area that will be covered by the

3. Tape into place. patch.


OPTION 2: Hole or Crack in Duct, RigidPlastic.

7. Press patch in place, and wrap glasstape around patch and duct to hold therepair in position.


LIMITATIONS: Inspect after every flight.15-6. FLEXIBLE DUCT DAMAGE.


MATERIALS/TOOLS REQUIRED: 0.016 inch Sheet Metal Minimum Sealant (item 4, Appx C) 400 Grit Sand Paper (item 45, Appx C) Cleaner Naptha or Equivalent

(item 7, Appx C) Glass Tape or Aluminum Tape

(item 60, Appx C)

PROCEDURAL STEPS:

1. Locate damaged area and removepanels and/or other items as necessaryto gain access to the duct to berepaired. Refer to Figures 15-2 and15-3 for locations of rigid plasticducts.

2. Cut a patch out of sheet stock.Patch should extend 1-1/2 inches fromthe edge of the hole at all points.

GENERAL INFORMATION: The flexible ductsare composed of special wire coveredfabric with impregnated rubber.

LIMITATIONS: These repairs are tem-porary and the damaged hoses should bereplaced as soon as possible. Inspectafter every flight.


MATERIALS/TOOLS REQUIRED: Glass Tape or Equivalent

PROCEDURAL STEPS:

1. Locate damaged area and remove panelsand/or other items as necessary to gainaccess to the duct to be repaired. Referto Figures 15-2 and 15-3 for locations offlexible plastic ducts.

15-8

4.


2. Wrap glass tape several turns around 3. Record BDAR action taken. Whenduct to cover hole or tear. Tape should mission is completed or as soon asextend beyond damaged area 3 to 4 inches feasible, replace duct using standardin each direction. maintenance procedures.

Section III. BLEED AIR LINE DAMAGE

15-7. GENERAL INFORMATION. Damage tosome bleed air lines may be repairable.

SYMPTOM: Loss of Engine Torque and/orHigh Engine Oil Temperature.

LIMITATIONS: Inspect after everyflight.

PERSONNEL/TIME REQUIRED:● 1 Soldier● 1 Hour

MATERIALS/TOOLS REQUIRED:● Sheet Metal Patch - 0.016 in. Min.● Sealing Compound (item 4, Appx C)● Aluminum Tape (item 60, Appx C)● Clamps 0.032 inch or Safety Wire

0.042 inch (item 27, Appx C)

PROCEDURAL STEPS:

1. Locate damaged area and removepanels and other items as necessary togain access to the line to be repaired.Refer to Figure 15-6 for locations ofbleed air lines.

2. Cut patch from aluminum sheet metalto cover hole or other damage. Patchshould extend approximately 1 inch fromthe edge of the hole or damage at allpoints if possible.

3. Apply sealant around the hole areato be covered by the patch.

4. Place patch in position, and makesure patch fills the contour of theline.

5. Secure metal patch in place usinghose clamp, Figure 15-7. If hoseclamps are not available, secure inplace with safety wire. Turn pigtailto line.

6. Wrap aluminum tape around therepair. Tape should cover at least 2inches beyond the edge of repair.


15-9


Figure 15-6. Bleed Air Line Installation

15-10


Figure 15-7. Bleed Line Patch Repair

15-11/(15-12 Blank)

TM 55-1520-228-BD

MISSION EQUIPMENT




There are no BDAR repairs offered for the mission equipment.

16-1/(16-2 Blank)

CHAPTER 16

TM 55-1520-228-BD

CHAPTER 17

EMERGENCY EQUIPMENT




There are no BDAR repairs offered for the emergency equipment.

17-1/(17-2 Blank)

TM 55-1520-228-BD

APPENDIX A

REFERENCES




The following references of the issue in effect are required for use by repairpersonnel to accomplish the instructions set forth in this TM.

PUBLICATIONNUMBER TITLE

DA PAM 738-751 ................. Functional User’s Manual for the Army Mainte-nance Management Systems Aviation (TAMMS-A)

FM 3-5 ....................... NBC Decontamination

TM 55-1500-328-25 . . . . . . . . Aeronautical Equipment Maintenance ManagementPolicies and Procedures

TM 55-1520-228-10 . . . . . . . . Operator's Manual Army Model OH-58A/C HelicopterTM 55-1520-228-1,2 . . . . . . . Aviation Unit and Intermediate Maintenance

ManualTM 55-1520-228-CL . . . . . . . . Operator’s and Crewmember’s Checklist

A-1/(A-2 Blank)

TM 55-1520-228-BD

APPENDIX B

SPECIAL OR FABRICATED TOOLS




Section I. GENERAL

B-1. SCOPE. This appendix lists spe- and durable supplies not listed in othercial tools and test equipment. Several appendices. Each kit contains its ownspecial tools are contained in the BDAR inventory list and tool usage instruc-kits listed on the next page. The kits tions. There are no fabricated toolsalso contain small quantities of parts associated with this BDAR manual.

Section II. TOOLS

B-2. SPECIAL TOOL LISTINGS. The items levels to accomplish battlefield damagelisted in this appendix will enhance assessment and repairs.crew members and mechanics at all

TM 55-1520-228-BDAPPENDIX B

SPECIAL OR FABRICATED TOOLS

NO. NSN DESCRIPTION

1 Not Assigned Composite Structures Repair Kit

2 5935-01-161-5883 Connector Repair Kit (Special Tools(11851) DMC658 for Electrical Connector Repair)

3 4920-01-266-7535 Emergency Repair Kit (Special and(11851) DMC895 Common Tools for Electrical Repair,

including Repair Parts)

4 4920-01-266-7534 Fluid Line Repair Kit (Special and(78286) Common Tools for Tubing and Hose70700-20900-041 Repair, Including Repair Parts)

5 Not Assigned Fuel Cell Repair Kit

6 Not Assigned High Energy Laser Damage AnalysisTest Kit

7 Not Assigned Optical Component Repair Kit

8 Not Assigned Standard Structures Repair Kit

9 4920-01-266-7536 Test Equipment Repair Kit (Electrical(78286) Test Equipment)70700-20638-041

10 5935-01-254-1688 Wire Repair Kit (Special Tools Used(06090) MK-0015-1 for Electrical Wiring Repair,

Including Repair Parts)

B-2

ITEM

TM 55-1520-228-BD

APPENDIX C

EXPENDABLE/DURABLE SUPPLIES AND MATERIALS LIST




Section I.

C-1. SCOPE. This appendix lists expen-dable supplies and materials needed tomake BDAR fixes on the OH-58 helicopter.Items are listed alphabetically by theitem shown in the description column.These items are authorized to you byCTA 50-970, Expendable Items (ExceptMedical, Class V, Repair Parts,Heraldic Items) or CTA 8-1OO.

C-2. EXPLANATION OF COLUMNS.

and

a. Item Number. This number isassigned to the entry in the listing andis referenced in the narrative instruc-tions to identify the material (e.g.,“Use cleaning compound, item 5, AppendixC“).

INTRODUCTION

b. National Stock Number. This isthe National stock number assiqned tothe item; use it to request orrequisition the item.

c. Description. Indicates theFederal item name and, if required, adescription to identify the item. Thelast line for each item indicates theCommercial and Government Entity Code(CAGEC) in parentheses followed by thepart number.

d. Unit of Issue (U/I). Is the abbre-viation of the types of units under whichmaterial is issued.

C-1

TM 55-1520-228-60APPENDIX C

APPENDIX C

Section II. EXPENDABLE SUPPLIES AND MATERIALS LIST

ITEM UNIT OFNUMBER NSN DESCRIPTION ISSUE

1

2

3

4

5

6

9

10

11

12

13

1415

16

17

18

21

22

23

24

5330-00-192-5051

8040-00-932-1945

8040-00-944-7292

8030-00-723-4599

8040-00-514-1880

8040-00-941-9984

6810-00-238-81197920-00-514-2417

5940-00-280-3499

8030-00-057-2354

4730-00-289-5909

4730-00-908-3193

8030-00-231-2345

5310-00-297-37515940-00-296-5326

8305-00-530-0109

8305-00-530-0111

8135-00-982-08845330-00-291-16055330-00-467-3615

9150-00-944-8953

9150-00-985-7246

9150-00-506-8497

9150-00-237-2388

Abrasive Cloth (Grit 180)P-C-451Adhesive, ENA934 NA B/AType II, Class 3 (81348)Adhesive, Epoxy Metal Set A4(33564) EA9340Adhesive, EX1675-B2 Pro Seal890-B2Adhesive, General Purpose(81348) EC1300121Adhesive, Silicone Rubber(80244) MIL-A-46106Aliphatic Naphtha (81348) TTN95Brush, Stiff Fiber Bristle(80244) H-B-643Cap, Electrical Crimp(96906) MS25274-2Chemical Conversion Coating(Alodine) (80244) MIL-C-81706Clamp, Hose, 3/8 to 1 in.(70403) MIL-C-11569Clamp, Hose, 1-1/16 to 2 in.(01944) MS35842-12Corrosion Preventive Compound(80244) MIL-C-16173Cotter Pin Assortment (81348)Ferrul, Electrical, 22-14 WireGage size (10 ea) (59730)Fiberglass Cloth (81349)MIL-C-9084Fiberglass Resin (81349)MIL-C-9084Foil, Aluminum QQ-A-1876Gasket, Cork 1/32 in.Gasket, Material 1/32 in.(81348) HH-P-96Grease, AircraftMIL-G-81322 (54527)Grease, Aircraft AeroShell Grease (54527)Grease, Aircraft DriveshaftCouplingJet Engine Lubricating Oil(Grade 1010) (98308)

PG

CN

KT

KT

KT

TU

GLEA

EA

GL

EA

EA

CN

KTEA

RO

CN

BXSHSH

CN

CN

TU

QT

C-2

78

1920

TM 55-1520-228-BDAPPENDIX C

APPENDIX C

Section II. EXPENDABLE SUPPLIES AND MATERIALS LIST (Cont)


25

26

27

28

29

30

3132

33

3435

3637383940

41

4243

44

45

464748

4950515253

9505-00-596-5101

9505-00-293-4208

9505-00-331-3275

9150-00-186-6681

9150-00-180-6266

9150-00-782-2627

5310-00-297-37515330-00-966-8657

9250-00-250-0926

8010-00-082-24508030-00-664-4968

5320-00-006-49125320-00-117-68265320-01-033-81795320-01-839-21465320-01-937-5448

5320-00-721-5211

5330-00-060-82125330-00-244-7201

5330-00-721-8117

5350-00-224-7203

5350-00-619-91676850-00-264-90385940-00-500-8723

5970-00-419-87237510-00-074-51245970-00-812-73877510-00-266-67127510-00-754-2522

Lockwire, Steel 0.020 (81348)QQ-W-423Lockwire, Steel 0.032 (81348)QQ-W-423Lockwire, Steel 0.041 (81348)QQ-W-423Lubricating Oil MIL-L-2104(Grade 30) (15958)Lubricating Oil, MIL-L-23699(81349)Lubricating Oil, MIL-L-7808(81349)Nut Assortment (81348) FFN836Packing, Preformed Assortment(51808) MAOK311Petroleum, Technical USP,White VV-P-236Primer, Epoxy Polyamide MIL-P-23377Putty, Chromate (81349)MIL-P-8116Rivet, Blind (92215) RV11OO-4-3Rivet, Blind (96906) MS2040AD4-4Rivet, Blind (81349) MIL-R-7885/6Rivet, B1ind (80205) NAS1738M4-3Rivet, Blind (11818) 3/16 in.CR2249-5-5Rivet, Solid Aluminum A470 A4-6(88044)Sandpaper, 600 GritSandpaper, 400 Grit, A-A-1200(58536)Sandpaper, 180 Grit, A-A-1200(80244)Sandpaper, 320 Grit, A-A-1047(58536)Sandpaper, 80 Grit, PP101 (81368)Solvent, Cleaning, P-D-680 (81348)Splice, Conductor, Crimp StyleWire Size 10, MS25181-3 (96906)Tape, Electrical, Black InsulationTape, Green (58536) A-A-1586Tape, Teflon (82577)Tape, A-A-883 (58536)Tape, A-A-113 (58536)

RO

RO

RO

QT

QT

QT

PGPG

CN

KTRO

BXBXBXBXBX

BX

SHSH

SH

SH

SHBBLEA

RORORORORO

C-3

TM 55-1520-228-BDAPPENDIX C

APPENDIX C

Section II. EXPENDABLE SUPPLIES AND MATERIALS LIST (Cont)


54 5940-00-283-5380 Terminal, Lug Crimp Style Stud, BXSize 6, Wire Gage 16-14

55 5940-00-143-4780 Terminal, Lug, Crimp Style Stud, BXSize 10, Wire Gage 16-14

56 5940-00-143-4777 Terminal, Lug (81349) MIL-T-7928 BX57 5940-00-804-9184 Terminal, Quick Disconnect BX

Wire Gage 16-14, MS27429-2(96906)

58 5940-00-804-9185 Terminal, Quick Disconnect, BXSize 18, MS27429-1 (96906)

59 6810-00-664-0387 Trichloroethane, 1-1-1, T-620 CN(81348)

60 6515-00-324-5500 Tongue Depressor, LLL-S-007,20 BX(81348)

61 61409-00-252-6499 Wire, Insulated, Size 14, RLBB74-50072 (46522)

62 6145-00-435-8613 Wire, Insulated, Size 18, RLM81044/12-18-9 (81349)

NOTE

● For expedient repair of flex hoses and metal tubes, refer totables listed in Chapter 9.

● AMC/BDR kits contain all necessary tools, materials, and testequipment for electrical repairs.

C-4

TM 55-1520-228-BD

APPENDIX D

SUBSTITUTE MATERIALS/PARTS




Section I.

D-1. SCOPE. This appendix containslists and tables of substitute materialsand parts which can be used on the OH-58aircraft for BDAR fixes.

D-2. GENERAL. The lists and tables forAppendix D are made up of the following:

a. Essential spare parts, Table D-1.

b. Spare and repair parts, Table D-2.thru D-3.

c. Fuels, Table D-4 thru D-7.

d. Lubricants and hydraulic fluids,Table D-8.

e. This appendix contains generalinformation concerning types, uses, andeffects of POL substitutes, and methodsof purging and flushing systems.

f. Some products are made up of che-mical ingredients which are not com-patible with products used on an OH-58aircraft. Some fuels, oils, andhydraulic fluids can have an adverseeffect on systems and components withthe OH-58 systems; therefore, it isadvisable to properly identify theproduct by specification number and namefrom cross-reference with primary andexpedient products available.

g. National stock numbers are used inconjunction with specification numbersto distinguish them from foreign pro-ducts. The identification of (NATO)product numbers relate directly to U.S.Military Specification numbers and thusare considered direct replacements.

INTRODUCTION

h. In some situations, petroleum, oil,lubricant (POL) substitute products offriendly or enemy nations can be used;however, CAUTION should be exercised dueto the possibility of sabotage. If thereis no other alternative but to use enemyproducts, check for signs of contamina-tion, discoloration, smell and thickness.

i. Once a product under considerationis identified as described above, itwill fall in one of three categories.These categories are defined as follows:

(1) Primary products. These arebasic products for which the system wasdesigned. The system will functionwithout limitation.

(2) Alternate Product. These areproducts that closely match the primaryproduct and may result in some reducedperformance with no effect on systemdurability. There are no limitations onduration of use.

(3) Emergency/Expedient Products.

(a) These are products that canbe used for only short periods of time.These products are to be used as a lastresort. These products will cause poorperformance and system damage after pro-longed use.

(b) It is important that thedistinction between these categories isunderstood. Since the choice betweenproducts could mean the differencebetween completing the mission andlimping home.

D-1

TM 55-1520-228-BDAPPENDIX D

APPENDIX D

ITEMNO.

23456789

101112131415161718

2021222324252627282930

Table D-1. Essential Spare PartsNATIONAL STOCK

NUMBER

2995-00-134-4543

1005-06-938-82266140-00-228-84475306-00-616-64725306-00-655-74435306-00-616-64715306-00-806-76975306-00-774-89155306-00-582-57235306-00-816-09485306-00-292-82845306-00-150-90835306-00-156-25335306-00-206-49115306-00-141-45111005-00-832-45491005-00-921-62412925-00-444-11865310-00-807-14745310-00-844-48725310-00-807-14675310-00-807-14755310-00-807-14695340-00-921-51355305-00-X86-30115305-00-206-2036

5310-O0-167-07665310-00-167-0765

Actuator, Electro-MechAmmunition Gage BlockAmmunition Chute 7.62Battery, StorageBoltBolt, NAD 1304-8BoltBoltBoltBolt, NAS 1305-8BoltBoltBoltBoltBoltBoltDrive MotorFeeder, Delinker Mau-56/AIgniter ExciterNutNutNutNutNutPin, Quick ReleaseScrews, MetalScrews, WoodTime Delay Relays (TDR’s)Washer, FlatWasher, Flat

D-2

1

19

DESCRIPTION

• • •

• • •


Table D-2. Spare and Repair Parts

NOUN/NSN

PUMP SUBMERGED2915-01-124-5222 x x x x x x xLINEAR ACTUATOR2995-00-134-4543 x

FORCE GRADIENT CYL.1680-00-126-4350 x

IGNITER EXCITER2925-00-444-1186 x

PRESSURE ALTIMETER6610-00-179-5254 x x x x x x

ATTITUDE INDICATOR6610-00-150-6583 x x

COURSE INDICATOR5826-00-505-3094 x x x x x x

PRESSURE ALTIMETER6610-00-179-5242 x x x x x

VERTICAL SPEED IND.6610-00-935-4278 x x x x x x

VOLTMETER INDICATOR6625-00-003-8745 x x x x x

PRESSURE ALTIMETER6610-00-110-3368 x x x x x x x xVERTICAL SPEED INDICATOR6610-00-029-6703 x x x x x

TRANSPONDER5895-00-160-2198 x x x x x x x xMOUNT5895-00-063-9498 x x x x x x x x xCONTROL5895-00-089-4403 x x x X X X x x xMOUNT5895-00-919-9513 x x x x X x x x x xANTENNA5895-00-935-4975 x x x x x x x x

D-3

U U A A A A A U E H U U U U U U U U U A CH H H H H H H H H H H H H H H H H H H H H5 6 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 6 48 A E S F P T H H H V M E K L F P N O 4 7


Table D-2. Spare and Repair Parts (Cont)

NOUN/NSN

MOUNT5895-00-935-9582 x x x x x x x x

UHF RADIO SET5821-00-138-7990 x x x x x x x

COMPENSATOR6605-00-487-4773 x x x x x x x x x x

DIRECTIONAL GYRO6615-00-167-9757 x x x x x x x

COMPASS TRANSMITTER6605-00-531-2992 x x x x x x x x x x

AN/ARC-1145821-00-935-5071 x x x x x

RADIO SET AN/ARC-1155821-00-935-5072 x x x x x

INVERTER5841-01-140-0941

ELECTRICAL INDICATOR6620-01-065-3740 x x x x x x

HOT AIR MIXING VALVE4810-01-089-4105 x

N1 INDICATOR,GAS PRODUCER6620-01-032-3937 x

INDICATOR TURN & BANK6610-00-169-1627 x x x x x x

MAGNETIC BRAKE1680-00-909-8098 x x x x x x x x x x x x x x x

PRESSURE ALTIMETER6610-00-935-4323 x x x x x x x

ATTITUDE INDICATOR6610-01-029-6702 x x x x x

ICS5895-00-895-4175 x x x x x x x x x x

D-4


NOTE 2: All subcomponents of the major components may be removed and substituted; however, the level ofdisassembly must be consistent wlth the field tools and skill levels available.

D-5

Table D-2. Spare and Repair Parts (Cont)

T a b l e D - 3 . W e a p o n s


Section II. FUELS

B-3. SCOPE. This section explains theuse of substitute fuels to be used onthe OH-58 helicopter. Table D-4 listssome possible U.S. fuels in properpriority that may be used. Table D-5lists primary or standard fuel sourcesand alternate fuel sources for variouscountries. Table D-6 lists some commer-cial fuel sources that may be substi-tuted for the primary or standard JP-4fuel and also some alternate fuel sour-ces which are similar to JP-5 and JP-8.

B-4. GENERAL. When fuel is pumped intoa combustion chamber with the correctair mixture, it can be ignited and willburn in a controlled manner. The spe-cial additives the fuel contains pre-vents carbon deposits and corrosionbuild up which in turn helps engineperformance.

B-5. MANNER OF BLENDING FUELS.

a. The fuel to be used on an OH-58helicopter has to meet certain charac-teristics so that starting and perfor-mance will be satisfactory. Thesecriteria are viscosity, pour point, andcloud point.

b. Some substitute fuels which alonecannot be used on the OH-58 helicoptercan be blended with a primary fuel andcan then be utilized for engineoperation.

c. When using substitute fuels, it ispreferable to premix the fuels in acontainer for better blending beforepouring into tank. This method ofmixing the primary fuel with a substi-tute fuel insures that the fuels mixcompletely. The best expedient fuelingmethod is to add both fuels at the sametime from two separate fuel lines.Table D-7 lists alternate and expedientfuel blends.

d. There is no special limitation onthe use of Army standard fuel or alter-nate fuel. When using an emergencyfuel, a fuel mixture which contains over10 percent leaded gasoline is consideredto be all leaded fuel. When using anemergency fuel, an entry on the faultsand remarks column of DA Form 2408-13,Inspection Record, should be made. Theentry should annotate the type of fuel,additives, and duration of operation.

e. Fuels having the same NATO codenumber are interchangeable, and fuelsconforming to ASTM-D-1655 specificationmay be used when standard fuelMIL-T-5624-JP4 is not available. Referto Table D-4.

D-6


PRIMARY FUEL

Aviation Tur-bine: MIL-T-5624(JP4)NATO-F-40

Table D-4. Substitute

ALTERNATE FUEL

MIL-T-5624(JP-5)NATO-F-44

Aviation Turbine:ASTM-D-1655(Jet B)

Aviation Turbine:MIL-T-83133(JP-8) NATO-F-34

Aviation Turbine:ASTM-D-1655(Jet A-1)

Fuels for JP-4

EXPEDIENTFUEL

Kerosene:ASTM-D-3699

Kerosene:NATO-F-5B

MIL-G-5572(Any AVGAS)NATO-F-12,F-18, F-22

FuelMILITARYSPECIFI-CATION

x

x

x

x

x

x

COMMERCIALSPECIFI-CATION

x

x

D-7


Table D-5. Fuels for The OH-58 HelicopterSource Primary or Standard Fuel Alternate Fuels

U.S. Military FuelNATO Code No. JP-4(MIL-T-5624) JP-5(MIL-T-5624) JP-8(MIL-T-83133)FOREIGN FUEL NATO F-40 NATO-44 NATO-34

TURBINE FUEL, TURBINE FUEL, TURBINE FUEL,PRODUCT AVIATION TYPE: AVIATION: AVIATION: -

DESCRIPTION Wide cut type High Flash Type Kerosene Type+(S-748) +(S-748)

BELGIUM BA-PF-2B AMD.2 BA-PF-6a/AF n/AF BA-PF-7 (AF)

CANADA 3-GP-22F n/AF 3-GP-24h n/(AF)DENMARK MIL-T-5624 D.Eng.RD.2453

Grade JP-4 a/AF Iss.3Amd.2 n/a/(AF)FRANCE AIR 3407/B AF AIR 3405/C n/a/AFFEDERAL REPUBLIC TL 9130-006 Iss.4 TL 9130-007 Iss.4OF GERMANY n/a/AF n/(AF)

Grade JP-4 n/AFITALY AA-M-C.142p AA-M-C.143b AA-M-C.141d

n/a/AF n/(AF) Amd.1 (AF)

LUXEMBOURGNETHERLANDS MIL-T-5624 D.Eng.RD.2498 D.Eng.RD.2453

Grade JP-4 a/AF Iss.6Amd.2 n/(AF) Iss.3Amd.2 a/AFNORWAY MIL-T-5624

Grade JP-4 AFPORTUGAL MIL-T -5624

Grade JP-4 AF AIR 3405/C AFTURKEY MIL-T-5624

Grade JP-4 a/AFUNITED KINGDOM D.Eng.RD.2454 D.Eng.RD.2498 D.Eng.RD.2453

Iss.3Amd.2 n/a/AF Iss.6Amd.2 n/a/(AF) Iss.3Amd.2 a/AFUNITED STATES MIL-T-5624 MIL-T-5624 MIL-T-83133

Grade JP-4 n/alAF Grade JP-5 n/(AF) JP-8GOST 1842-52

USSR GOST 10227-62T-1, TS-1 GOST 9145-59

D-8

GREECE MIL-T-5624


Table D-6. Substitute Commercial Fuels

SOURCE PRIMARY OR STANDARD FUEL ALTERNATE FUELS

U.S. MILITARY FUEL JP-4(MIL-T-5624) JP-5(MIL-T-2624) JP-8(MIL-T-83133)NATO CODE NO. F-40 F-44 F-34

COMMERCIAL FUEL(ASTM-D-1655) JET B JET A JET A-1

American Oil Co. American JP-4 American Type A

Atlantic Richfield Arcojet B Arcojet A Arcojet A-1Richfield Div Richfield A Richfield A-1

B.P. Trading B.P.A.T.G B.P.A.T.K.

Caltex PetroleumCorp. Caltex Jet B Caltex Jet A-1

City Service Co. CITCO A

Continental Oil Co. Conoco JP-4 Conoco Jet-50 Conoco Jet-60

Exxon Co. U.S.A. Exxon Turbo Fuel B Exxon A Exxon A-1

Gulf Oil Gulf Jet B Gulf Jet A Gulf Jet A-1

Mobil Oil Mobil Jet B Mobil Jet A Mobil Jet A-1

Phillips Petroleum Philjet JP-4 Philjet A-50

Shell Oil Aeroshell JP-4 Aeroshell 640 Aeroshell 650

Sinclair Superjet A Superjet A-1

Standard Oil Co. Jet A Kerosene Jet A-1 Kerosene

Chevron Chevron B Chevron A-50 Chevron A-1

Texaco Texaco Avjet B Avjet A Avjet A-1

Union Oil Union JP-4 76 Turbine Fuel

D-9


Table D-7. Alternate and Expedient Fuel Blends

BASE FUEL EXTENDER (50% MAXIMUM)

NOTE

Fuel may be extended on an alternate basis with the followingblends up to a half and half mixture.

Any Primary Fuel

Any Primary Fuel

Any Primary or Alternate Fuel

Any Primary or Alternate Fuel

Any Alternate or Primary Fuel

Any Alternate Fuel

Any Alternate Fuel

MIL-F-815 Distillate

NATO-F-76 Navy Distillate

Dry Cleaning Solution:P-D-680 (Type I and II)

Dry Cleaning Solution:AMSTM-D-484 (K, I, II, III, IV)

Petroleum Spirits: ASTM-D-235(I, II, III, IV)

CAUTION

The helicopter shall not be flown when emergency fuel hasbeen used for a total cumulative time of 50 hours.

D-10


Section III. LUBRICANTS AND

D-6. SCOPE. This section lists pri-mary, alternate, and expedient lubri-cants and hydraulic fluids.

D-7. GENERAL.

a. The lubricants and hydraulicfluids used in OH-58 systems and com-ponents must have a compatible basecomposition, as well as good additivelevel. Being that the purpose of lubri-cants and hydraulic fluids is to reducewear, support bearing loads, and providecooling, their chemical composition mustbe compatible. In addition to lubri-cating, hydraulic fluids must transmitpower and motion. If two incompatiblehydraulic fluids are mixed, there is atendency of a gel substance formingwithin the system and ruining it.

b. Some lubricants will not with-stand OH-58 temperatures or loads forextended periods of time. These type oflubricants do not contain the necessarybase properties for withstanding longterm performance; therefore, they arerecommended only as a last resort.

c. Expedient lubricants can causeone of three problems.

(1) They may not allow properefficient operations because of improperviscosity.

HYDRAULIC FLUIDS

(2) They may allow an increase inwear because of improper viscosity.

(3) They may cause seals to swellor create deposits because of impropercomposition.

D-8. LUBRICANTS AND HYDRAULIC FLUIDS.Table D-8 lists the primary lubricantsand hydraulic fluids which are used asprimary, alternate, and expedient useson the OH-58 helicopter.

CAUTION

Lubricating oil MIL-L-23699 shallnot be used in ambient tem-peratures below minus 32°C/25°F.

NOTE

It is not advisable to mixMIL-L-7808 and MIL-L-23699 oils,except during an emergency. Ifoils are mixed, the system shouldbe flushed within six hours. Anentry on DA Form 2408-13 isrequired when the oils are mixed.Hydraulic oils MIL-L-83282 andMIL-L-5606 should not be mixedexcept during an emergency. Whenthese oils are mixed with eachother or any other oil, a DA Form2408-13 entry is required.

D-11/(D-12 Blank)

TM 55-1520-244-BD

APPENDIX E

BDAR FIXES AUTHORIZED FOR TRAINING




REPAIR PROCEDURE

AIRFRAME

Honeycomb Core Floor or Panel Damage . . . . . . . . .

DRIVE TRAIN SYSTEM

Air Duct Hose Damage . . . . . . . . . . . . . . . . .

HYDRAULIC SYSTEM

Lines and Hoses. . . . . . . . . . . . . . . . . . . .Aluminum Tube Damage . . . . . . . . . . . . . . . . .Hydraulic Hose Damage . . . . . . . . . . . . . . . . .


Splicing Unshielded Wires . . . . . . . . . . . . . .Damaged Wire Insulation . . . . . . . . . . . . . . .Shielded Cable Repair . . . . . . . . . . . . . . . .Shielded Cable Repair Segments . . . . . . . . . . . .Shielded Terminators . . . . . . . . . . . . . . . . .Terminators for Nickel-Plated Shields (including

vermillion). . . . . . . . . . . . . . . . . . . . .Terminal Boards. . . . . . . . . . . . . . . . . . . .Terminal Lugs. . . . . . . . . . . . . . . . . . . . .Wire Bundle Tie Wraps.... . . . . . . . . . . . . .Coax Splice for RG-136/U and RG-179 R/U. . . . . . . .Bus Bars. . . . . . . . . . . . . . . . . . . . . . .Battery Repair BB-476/A. . . . . . . . . . . . . . . .Substitute Emergency Antenna, Field Expedient. . . . .

PARA NO.

4-22

8-6

9-59-79-8

11-511-711-811-911-10

11-1111-1211-1311-1411-1511-2211-2311-25

E-1

TM 55-1520-228-BDAPPENDIX E

BDAR FIXES AUTHORIZED FOR TRAINING (Cont)

REPAIR PROCEDURE PARA NO.

FLIGHT CONTROL SYSTEM

Tubes, Flight Control . . . . . . . . . . . . . . . . . 13-4

ENVIRONMENTAL CONTROL SYSTEM

Rigid Plastic Ventilation Duct . . . . . . . . . . . . 15-5Flexible Duct Damage . . . . . . . . . . . . . . . . . 15-6Bleed Airline Damage . . . . . . . . . . . . . . . . . 15-7

E-2

TM 55-1520-228-BD

APPENDIX F

AVIONICS CONFIGURATIONS





F-1. SCOPE. This appendix lists anddepicts the major components, cableroutes, and wiring terminations per-taining to the OH-58 series helicopteravionics. This information is fur-nished as an aid to expedient repairtechniques described in Chapter 11.

F-2. GENERAL. The actual configura-tions may vary depending on particularrequirements or changes incorporatedthrough modification work order (MWO)action and special purpose alterations.

The Figures F-1 thru F-10 show typicallocation of avionics and their associatedcomponents in relation to the helicopter,and lists the component part number.Each figure also has a table associatedwith the avionics system which containsa complete wire listing to be used asan aid in rapid wire splicing. Thisincludes the wire number, type (shielded,not shielded, or pair twisted withshield), end connectors, and the pinnumbers on each connector.

F-1

TM 55-1520-228-BDAPPENDIX F

Figure F-1. Intercom System (Sheet 1 of 2)

F-2



23456

89

101112

TJ11E-02-011021-DOO1U92AUJF13E01-02U94A/UU92AUC-6533/ARCC-6533/ARCC-6533/ARCMS25039-1JF13E01-04206-075-483-1

Module, Terminal JunctionAudio ThresholdJack, TelephoneFrame, ElectronicPlug, ConnectorJack, TelephoneControl, IntercomControl, IntercomControl, IntercomSwitch, PushRack, ElectronicNetwork, Impedance Matching

13 PC4D2D22-4 Connector, Recepticle14 TJ11E02-02 Terminal Board

Figure F-1. Intercom System (Sheet 2 of 2)

Table F-1. WiringWIRE NUMBER TYPE 1

C6533A-3A22 (RED)-1A22 (GRN)-45A22-1OA22-14A22-18A22

C6533B-3A22 (RED)-1A22 (GRN)-45A22-1OA22-14A22-18A22

C6533C-3A22 (RED)-1A22 (GRN)-45A22-1OA22-14A22-18A22

PR/SPR/SSHIELDSHIELDSHIELDSHIELD



Table,END 1

P214P214P214P214P214P214

P215P215P215P215 LP215 KP215

P213P213P213P213 LP213P213

IntercomPIN

CAPLRV

CAP

V

AP

KV

1 Denotes: PR/S--Pair, Twisted, with Shield

END 2

TB21TB21TB19TB19TB19TB19

TB21TB21TB19TB19TB19TB19

J309J309TB19TB19TB19TB19

PIN

AZC1C1A3C3A1

A7A8D1B3D3B1

D2B4D4B2

F-3

1

7

C

System


NOTETHIS UNIT IS A CONTROL PANELONLY IN AIRCRAFT USINGAN/ARC-51BX TRANSMITTER

Figure F-2. UHF/AM Communication System (Sheet 1 of 2)

F-4


DRAWINGDESIGNATION

678

PARTNUMBER

HPF40-O1T

KD-59-04AN/ARC-51BXC-6287/ARC-51BXAN/ARC-116AN/ARC-164KO-59-04AS2487KA-59-119

FUNCTION

Filter, High PassConnector, ElectricConnector, PlugTransceiver, UHF, RT-742()Control, Panel

Connector, PlugAntenna, UHFConnector, Plug Electric

Figure F-2. UHF/AM Communication System (Sheet 2 of 2)

Table F-2. Wiring Table UHF/AM Communication System WIRE NUMBER

OH-58A

ARC51-124A20-125A20-128A20 (RED)-129A20 (BLK)-131A20-140A

*ARC116-10A22-101A-101B

*SAME WIRING USEDFOR AN/ARC-164.

OH-58C

ARC116-1OB22 (RED)

-11B22 (BLK)

-101A

-101B

SHIELDSHIELDPR/SPR/SSHIELDCOAX

SHIELDCOAXCOAX

PR/S

PR/S

COAX

COAX

END 1

P403P401P403P403P403P404

P203P204P313

P203

P203

P204

J313

1 Underlined Pin Numbers Denote Lower Case.

2 PR/S---Pair, Twisted, with Shield

PIN END 2

RFVEU

K

K

L

P401J405J405J405J405J406

TB19P314P304

J252

J252

P314

P304

PIN 1

D6

B6

F-5

12345

TYPE 2

EdKLe

C4


Figure F-3. VHF/AM Communication Systemand Connecting Cables (Sheet 1 of 2)

F-6



KC-59-212BPF40-03PJT06RE18-32SKC-59-212KD-59-04AN/ARC-115KC-59-196KC-59-198KC-19-120

Connector, PlugFilter, Band PassConnector, PlugConnector, PlugConnector, PlugConnector, PlugConnector, PlugConnector, ElectricConnector, Electric

Figure F-3. VHF/AM Communication Systemand Connecting Cables (Sheet 2 of 2)

Table F-3. WIRE NUMBER

OH-58A

ARC115-1OA22-101A-101B

ARC115-101C

OH-58C

ARC115-1OB22 (RED)-11B22 (BLK)-101A-101B

ARC115-101C

Wiring Table, VHF/AM Communication SystemTYPE END 1 PIN END 2 PIN

SHIELD P205 K TB19 A4COAX P206 P31OCOAX P311 P243

COAX J243 P246

P205 K J252 D5P205 L J252 D6

COAX P206 P31OCOAX P311 P243

COAX J243 P246

F-7

123456789



2345678

91011

1213

LPF-40-028204-075-850-9AN/ARC-114AN/ARC-114C-8157/ARCAS-2485AS-2670/ARCTSEC/KY-28TSECIKY-58AS-2486/ARCLPF40-028206-022-114-1

206-022-114-3KC-59-212KC-19-120

Filter, Low PassBoard, Capacitor, A3Radio Set, No. 1 FMRadio Set, No. 2 FMControl, Indicator TSEC/KY-28Antenna, No. 2 FMAntenna, R/H, No. 1 FMCom Security SetCom Security SetAntenna, L/H, No. 1 FMFilter, Low PassAntenna, No. 1 FM, USBL on68-16687 thru 72-21454USBL on 72-21455 and Subq.Connector, PlugConnector, Electrical

Figure F-4. VHF/FM Communication System

F-8

1


Table F-4.WIRE NUMBER

OH-58A

1ARC114-2A22-9A22-1OA22-11A22-17A22-18A22-19A22-26A22-27A22-28A22-101A-101B-101C-102A-103A

2ARC114-1OA22-101A-101B

OH-58C

1ARC114-2A22-9A22-1OA22-11A22-17A22-18A22-19A22-26A22-27A22-28A22-101A-101B-101C-102A-103A

2ARC114-11B22-20B22-101A-101B

(BLK)(RED)

SHIELDSHIELDSHIELDSHIELDSHIELDSHIELDSHIELDSHIELDSHIELDSHIELDCOAXCOAXCOAXCOAXCOAXSHIELDCOAXCOAX

SHIELDSHIELDSHIELDSHIELDSHIELDSHIELDSHIELDSHIELDSHIELDSHIELDCOAXCOAXCOAXCOAXCOAXPR/SPR/SCOAXCOAX

Wiring Table, VHF/FMEND 1

P209 BP209 JP209 KP209 LP209 TP209 UP209 VP209 cP209 dP209 eP21OP239J242P211P212P207P208P315

P209P209P209P209P209P209P209P209P209P209P21OP239P242P211P212P207P207P208P315

CommunicPIN 1

BJKLTuV

de

LK

1 Underlined Pin Numbers Denote Lower Case.

2 Denotes: PR/S---Pair, Twisted, with Shield

ation SystemEND 2

P201P249P249P250A3A3P201P249P249P250P237P242P245P241P240TB19P316P238

P201P249P249P250A3A3P201P249P251P250P237P242P245P241P240J252J252P316P238

VPVH21W

GK

C2

VPVH2

KDC2K

D4C5

F-9

TYPE 2

K

D

1

c

PIN


Figure F-5. Gyromagnetic Compass Set AN/ASN-43and Connecting Cables (Sheet 1 of 2)

F-10



1 CN-998()/ASN-43 Gyroscope, Displacement2 ID-1351()/A Indicator, Heading Bearing3 CN-405/ASN Compensator, Transmitter4 T-611A/ASN Transmitter, Induction5 MS3126E18-32S Connector, Plug6 MS3126E16-26S Connector, Plug

Figure F-5. Gyromagnetic Compass Set AN/ASN-43and Connecting Cables (Sheet 2 of 2)

Table F-5. WiringWIRE NUMBER TYPE

TN1705D2210A22 (BLU)11A22 (GRN)12A22 (YEL)13A2214A2215A2220A22 (BLU)21A22 (GRN)22A22 (YEL)

SHIELDTWT/STWT/STWT/SSHIELDSHIELDSHIELDTWT/STWT/STWT/S

P202P202P202P202P202P202P202P201P201P201

vwxYHJGFGH

1 Denotes: TWT/S---Three Wire Twisted, with Shield

P202P201P201P201P201P201P201TR101TR101TR101

PIN

TJKLCDE

CA

F-11

Table, Gyromagnetic Compass Set END 1 PIN END 2

B


Figure F-6. Direction Finder Set AN/ARN-89 (Sheet 1 of 2)

F-12


DRAWINGDESIGNATION

23456

Figure F-6.

ARN89-6C22-6B22-6A22

CG-3492/U() *-3493/U() *-3494/U() *-3495/U() *

CX-10960/U()OH-58C

ARN89-6C22-6B22-6A22

CG-3492/U() *CG-3493/U() *CG-3494/U() *CG-3495/U() *

CX-10960/U()

PARTNUMBER FUNCTION

C-7392()/ARN-89 Control, Radio SetID-1351()/A Indicator, Heading BearingR-1496()/ARN-89 Receiver, RadioAM-4859()/ARN-89 Amplifier, Impedance Matching206-032-310-3 Antenna, SenseAS-2108()/ARN-89 Antenna, Loop

Direction Finder Set AN/ARN-89 (Sheet 2 of 2)

SHIELDSHIELDSHIELD

COAXCOAXCOAXCOAX

SHIELD

SHIELDSHIELDSHIELDCOAXCOAXCOAXCOAX

SHIELD

Wiring Table,END 1

P227P227SPLICE

P223P222P220P221

P219

P227P227P227P223P222P220P221

P219

ADF AN/ARNPIN

FD

FD

*NOTE: Center Conductor of Coax Cable Has 28.0 V dc.

-89END 2

SPLICESPLICEP201

P225P224P217P226

P218

SPLICESPLICE3405S1P225P224P217P226

P218

PIN

N

10

Disconnect Before Using TDR.

F-13

1

WIRE NUMBERO H - 5 8 A

Table F-6.TYPE


Figure F-7. Radio Receiving Set AN/ARN-123(V)1 (Sheet 1 of 2)

F-14


DRAWINGDESIGNATION

23456

89

1011121314

PARTNUMBER

MS25041-4MS27786-23M39012/16-0004AS-3188/ARN5955-00-858-6552AS-3104()/ARNM39012/16-0004R-2023/ARN-123(V)1M39012/16-0004M39012/16-0004M39012/16-0004M39012/16-0004AT-640/ARNID-1347C/ARN

FUNCTION

Light, IndicatorSwitch, Toggle, Four PoleConnector, PlugAntenna, GlideslopeSpider, Coax Assembly (05211)AntennaConnector, PlugReceiverConnector, PlugConnector, PlugConnector, PlugConnector, PlugAntenna, Marker BeaconIndicator, Course

NOTE

IF ID-1347C/ARN-82 IS USED WITH THE AN/ARN-123(V), THESWITCH ON THE BACK OF THE INDICATOR MUST BE SET TO THER-1388A/ARN-82 POSITION.

Figure F-7. Radio Receiving Set AN/ARN-123(V)1 (Sheet 2 of 2)

Table F-7. Radio WIRE NUMBER TYPE 1

ARN123-20A22 (WHT) TWT/S-20A22 (BLU) TWT/S-20A22 (ORN) TWT/S-33A22 (WHT) TWT/S-33B22 SHIELD-33A22 (BLU) TWT/S-34A22 (BLU) SHIELD-33C22-34A22 (WHT) TWT/S-35A22 (WHT) PR/S-35A22 (BLU) PR/S-36A22 (WHT) PR/S-36A22 (BLU) PR/S-38A22 (WHT) PR/S-38A22 (BLU) PR/S-38B22-39A22 (WHT) PR/S-39A22 (BLU) PR/S-40A22 (WHT) TWT/S-40A22 (BLU) TWT/S-40A22 (ORN) TWT/S-41A20 (WHT) PR/S-41A20 (BLU) PR/S

Receiving Set AN/ARNEND 1

3405RE1P11OO13405RE1P11OO13405RE1P11OO13405RE1P120023405RE1P12002SPLICESPLICESPLICE3405RE1P120023405RE1P120023405RE1P120023405RE1P120023405RE1P120023405RE1P120023405RE1P12002SPLICE3405RE1P120023405RE1P120023405RE1P120023405RE1P120023405RE1P120023405RE1P120023405RE1P12002

1 Denotes: PR/S----Pair, Twisted, with Shield

123(V)1 OH-58CPIN END 2 PIN12 3405S1

SPLICESPLICE3405DS1P1 C

34 3405DS1P1 F15 3405CP1P111

4 3405CP1P1 192 3405CP1P1 177 P201 P6 P201 R10 GND18 3405T119 GROUND

TWT/S ---Three Wire Twisted, with Shield

F-15

1

7

1325 932

3405S13405S13405DS1P1SPLICE

369B

23 83336

3405DS1P13405DS1P13405DS1P13405DS1P1

HDEG

311

3405CP1P13405CP1P1


Figure F-8. Radar Altimeter System AN/APN-209 (Sheet 1 of 2)

F-16


DRAWINGDESIGNATION

Figure F-8.

PARTNUMBER FUNCTION

M39002/01-0072MS27473T10835SKA-59-96KA-59-96RT-1115/APN-209KA-59-96AS-2595/APN-194KA-59-96AS-2595/APN-194MS91528-0N18

Resistor, FixedConnector, Plug, ElectricConnector, PlugConnector, PlugIND., RCVR, TransmitterConnector, PlugAntennaConnector, PlugAntennaKnob, Control

Radar Altimeter System AN/APN-209 (Sheet 2 of 2)

Table F-8. Wiring Table, Radar Altimeter AN/APN-209 OH-58CWIRE NUMBER TYPE 1 END 1 PIN END 2 PIN

APN209-21A COAX 2408DS1P4 J4 3408E1P1 J1APN209-22A COAX 2408DS1P3 J3 3408E2P1 J1

F-17

1 2 3 4 5 6 7 8 910



23

4

5678

TS-1843()/APXRT-859()/APX-72C-6280A(P)/APXRT-1285/APX-100(V)

206-077-109-1

KIT-1A/TSECMT-3513/APXAT-884()/APXMT-3809/APX-72

Test Set, TransponderReceiver-TransponderControl, TransponderAPX Transponder: The APX-1OO(V),

Used On The OH-58C Does NotRequire The TS-1843()/APX

Antenna: Used Only On OH-58CWith APX-1OO

ComputerMountAntennaMount

Figure F-9. Transponder (IFF) System AN/APX-72, AN/APX-100

F-18

1


WIRE NUMBER

SX706A18SX706B18SX707A22SX712A22SX714A22SX716A22SX717A22SX719A22SX720A22SX721A22SX743A22SX754A22SX755A22SX756A22SX757A22SX758A22SX761A22SX762A22SX763A22SX764A22SX765A22SX766A22SX768A22SX803A22SX804A22SX817A22SX818A22SX819A22SX820A20SX821A22SX822A22SX823A22SX824A22SX825A20SX826A22SX834A20SX849A22SX701ASX701BSX828ASX829ASX830ASX831A

Table F-9. Wiring Table, IFF, APX-72 OH-58ATYPE END 1 PIN END 2

I I I ISHIELDSHIELDSHIELDSHIELDSHIELDSHIELDSHIELDSHIELDSHIELDSHIELDSHIELDSHIELDSHIELDSHIELDSHIELDSHIELDSHIELDSHIELDSHIELDSHIELDSHIELDSHIELDSHIELDSHIELDSHIELDSHIELDSHIELDSHIELDSHIELDSHIELDSHIELDSHIELDSHIELDSHIELDSHIELDSHIELDSHIELDCOAXCOAXCOAXCOAXCOAXCOAX

P234SPLICEP234P234P234P234P234P234P234P234P234P234P234P234P234P234P234P234P234P234P234P234P232P234P234P234P234P234P234P234P234P234P234P234P234P232P233P233P230P234P234P234P234

2

21201918161514

SPLICECB2P232P232P232P232P232P232P232P232

640

P233P232

393837

P232P232P232

3629

P232P232

282726

P232P232P232

2524

P232P232

129

10594344505657582234515119

45464748

TB6J600TB26P232P232P232P232P232P232P232P232P232P232SPLICEP232P236P235P233P233P233P233

PIN

242

115689

10312627282930323335363738C329B24

1516

1819

4255

3

23

F-19

4

17

2025

14


Table F-10. WiringWIRE NUMBER TYPE 1

IAPX1OO-5O48A22(WHT

-5048A22(BLU-5001A

APX1OO-5OO2A

APR39-31A

APX1OO-5O17A-5018A-5019A

APX1OO-5O2OA

PR/SPR/SCOAXCOAX

SHIELD

COAXCOAXCOAXCOAX

Table, IFF,END 1

341OTR1P1341OTR1P1341OTR5P1341OTR4P1

341OTR1P1

341OTR1P1341OTR1P1341OTR1P1341OTR1P1

2123

19

43454749

J600J600341OE1P2341OE1P1

3422Z1P1

341OU1P1341OU1P1341OU1P1341OU1P1

PIN

2928

22

4231

1 Denotes: PR/S---Pair, Twisted, with Shield

F-20

APX-100, OH-58CP I N END 2



23456789

10

AS-2892/APR-39(V)IP-1150()/APR-39AS-2891/APR-39(V)AS-2892/APR-39(V)R-1838()/APR-39AS-2890/APR-39(V)CM-440/APR-39(V)C-9326/APR-39(V)AS-2891/APR-39(V)R-1838()/APR-39(V)

Antenna, Left SpiralIndicator, Radar SignalAntenna, Right SpiralAntenna, Left SpiralReceiver, RadarAntennaComparatorControl, Detecting SignalAntenna, Right SpiralReceiver, Radar

Figure F-10. Radar Warning System AN/APR-39

F-21

1


Table F-11.WIRE NUMBER TYPE

OH-58A

APR39-1A-2A-3A-4A-9A-15A-17A-23A-30A22-30B22-30C22

COAXCOAXCOAXCOAXCOAXCOAXCOAXCOAXSHIELDSHIELDSHIELD

APR39-31A COAXOH-58C

APR39-lA-2A-3A-4A-9A

COAXCOAXCOAXCOAXCOAX

-15A COAX-17A COAX-23A COAX-30A22 SHIELD-30B22 SHIELD-30C22 SHIELD

APR39-31A COAX

END 1

3422Z1P13422Z1P13422Z1P13422Z1P13422Z1P23422DS1P13422Z1P13422Z1P13422A1P1TB20TB203422Z1P1

3422RE1P33422RE2P33422RE2P43422RE1P43422Z1P23422Z1P13422RE1P53422RE2P53422A1P1TB20TB203422Z1P1

PIN

818199

579

C16D1621

J3J3J4J4J25

J5J5

C16D1622

END 2

3422RE1P33422RE2P33422RE2P43422RE1P43422E1P13422Z1P13422RE1P53422RE1P4TB20P214P215P234

3422Z1P13422Z1P13422Z1P13422Z1P13422E1P13422DS1P13422Z1P13422Z1P1TB20P214P215341OTR1P1

PIN

5

C15LLLL11

818199

J15

LLLL19

F-22

Wiring Table, AN/APR-39

717C15

14

14

TM 55-1520-228-BD

Subject

Application, BDAR. . . . . . . . . .Allowable Damage Limits Definition .Allowable Damage Limits. . . . .Air Bleed Valve. . . . . . . . .Air Duct Hose Damage . . . . . .Aluminum Tubing Damage . . . . .Assessment Procedures

Airframe. . . . . . . . . . .Alighting Gear . . . . . . . .Drive Train System . . . . . .Electrical and Avionics SystemEnvironmental Control System .Flight Controls System . . . .Fuel Systems . . . . . . . . .Hydraulic. . . . . . . . . . .Power Plant . . . . . . . . . .Rotors. . . . . . . . . . . .Utility Systems. . . . . . . .

Battery Repair . . . . . . . . .BDAR Characteristics . . . . . .Bleed Air Line Damage. . . . . .Blending Fuels . . . . . . . . .Bus Bars. . . . . . . . . . . .

Cap or Longeron, Damage. . . . .Cap, Skin, Web, Doubler Damage .Circuit Protection Device RepairCoax Splicing . . . . . . . . .

Component Bridging . . . . . . .Condition, Airframe. . . . . . .Connector Repair . . . . . . . .

Paragraph

A

B

C

1-34-84-136-58-69-7

4-2

8-311-215-313-212-29-36-27-314-2

11-231-615-7D-611-22

4-184-1711-2111-15 thru11-1811-194-911-20

INDEX-1

INDEX

5-3

TM 55-1520-228-BDINDEX

Subject

D

Paragraph

Damage Measurement, Airframe . ..Damaged or Defective Power RelaysDamaged Wire Insulation. . . . .Definitions. . . . . . . . . . .Description - Power Plant. . . .Detail Assessment, Airframe. . .De-Ice Valve or Control Repair .Drive Train Component Damage . .Drive Train Damage . . . . . . .Double Check Valve Inoperative .

Emergency EquipmentE

Description - Emergency Equipment. . . . . . .

Supplementary Emergency Equipment Information.Environmental Control System

Bleed Air Line Damage. . . . . .Flexible Duct Damage . . . . . .Rigid Plastic Ventilation Duct .

Flexible Duct Damage . . . . . . .

F

Flight Controls System, Subsystems, and AssembliesFrame. Bulkhead, Skin and Stringer Damage. . . . .Fuel Cell Repair . . . . . . . . .Fuel Line Repair . . . . . . . . .Fuel Substitutions . . . . . . . .

General Fault Assessment Tables .

Hard Landings, Sudden Stops. . . . .Honeycomb Core Floor or Panel DamageHose and Line Replacement. . . . . .Hydraulic Fluid Substitutions. . . .Hydraulic Hose Damage. . . . . . . .

4-7, 4-1211-2411-7

6-14-614-48-58-26-6

19-119-2

15-715-615-5

15-613-44-1912-79-812-6

2-2

5-64-209-79-119-8

INDEX (Cont)

1-4

INDEX-2

G

H


INDEX (Cont)

Subject Paragraph

I

Initial Assessment, Airframe . . . . . . . . . . . . .

J

K

L

Lines and Hose Replacement . . . . . . . . . . . . . .Low Pressure Sensing Switch Leak . . . . . . . . . . .Lubricants and Hydraulic Fluids. . . . . . . . . . . .

M

Main Rotor Blade, Hole 1 to 4 Inches Diameter Maximum.Manner of Blending Fuels.. . . . . . . . . . . . . .

N

O

Oil Hoses and Lines, Leaks or Restriction (Crimp). . .Oil Lines (Rigid) Type Repair. . . . . . . . . . . . .Oil Pressure Transmitter Leak. . . . . . . . . . . . .0il Tank Punctured. . . . . . . . . . . . . . . . . .Operating Characteristics. . . . . . . . . . . . . . .O-Ring Damage. . . . . . . . . . . . . . . . . . . . .O-Ring, Packing, and Gasket Applications . . . . . . .

P

Purpose, BDAR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Q

Quality Deficiency Report/Equipment Improvement Recommendation . . . .

4-5

9-58-8D-6

7-7D-5

8-99-78-76-71-812-59-10

1-1

1-5

INDEX-3


R

Repair Plan, Airframe.Repair Procedure Index

Airframe . . . . . .Alighting Gear . . .Drive Train System .

4-10.

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4-14

11-315-413-312-3

7-114-31-1115-57-6

Electrical and Avionics SystemEnvironmental Control System .Flight Controls System . . . .Fuel Systems . . . . . . . . .Hydraulic. . . . . . . . . . .Power Plant . . . . . . . . . .Rotors. . . . . . . . . . . .Utility Systems. . . . . . . .

Reports. . . . . . . . . . . . .Rigid Plastic Ventilation Duct .Rotor Blade,Hole 1

of Driveinators .

Inch Diameter or Less.

S

SensitivityShield Term

Train System to. . . . . .

Shielded Cable Repair. . . . . .

Battlefield Damage. 8-511-1011-811-95-74-1611-54-411-2519-2

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Shielded Cable Repair Segments . . .Skid Damage. . . . . . . . . . . . .Skin-Stiffener Damage. . . . . . . .Splicinq Unshielded Wires. . . . . .Structural Damage Assessment and Repair.Substitute Emergency Antenna, Field Expedient.Supplementary Emergency Equipment Information.

T

1-104-228-1111-1211-1311-111-98-108-69-613-311-21

Tagging/Identifying BDAR Repairs .Tail Boom Skin Damage. . . . . . .Tail Rotor Gearbox, Bullet Damage.Terminal Boards. . . . . . . . . .Terminal Lugs. . . . . . . . . . .Terminators for Nickel-Plated ShieldsTraining. . . . . . . . . . . . .Transmission-Bullet Damage . . . .

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Transmission Oil Cooling Air Duct Repair .Tube Cutting. . . . . . . . . . . . . . .Tubes, Flight Control. . . . . . . . . . .Typical Avionics Configuration . . . . . .

. .

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5-48-4

9-46-3

INDEX-4

Paragraph

INDEX (Cont)

Subject

Subject


INDEX (Cont)

Paragraph

U

V

Waiver of Precautions. . . . . . . . . . . . . . . . . . . . . . . . . . . . Window Shield/Window Damage. . . . . . . . . . . . . . . . . . . . . . 4-21Wire Bundle Tie Wraps. . . . . . . . . . . . . . . . . . . . . . . . . 11-14Wire Repair Segments, Unshielded Wires . . . . . . . . . . . . . . . . 11-6

XYZ

INDEX-5/(INDEX-6 Blank)

1-7

W

TM 55-1520-228-BD

GLOSSARY

NOTE

The terms and acronyms listed herein are defined in relation toBDAR and accordingly may not be used in the same manner in othermanuals.

Additional definitions of terms, markings, and acronyms usedduring BDAR assessment procedures will be found under chapter1, paragraph 1-10, Tagging and Identifying BDAR Repairs.

ABRASION

ALLOWANCE

API

ASSEMBLY

ASSEMBLY CLEARANCE

ASSESSMENT

ASSOCIATED PARTS

AXIAL

BATTLEFIELD DAMAGE

BEAM

BEND

BORE

Roughened surface, varying from light to severe.

A prescribed difference between the maximum condition ofmating parts. The minimum clearance or maximum inter-ference between such parts.

Armor piercing incendary armament round.

A group of two or more physically connected and relatedparts, capable of disassembly, and when combined withother assemblies and parts, creates a component.

The actual fit between two or more mating parts withrespect to the amount of clearance or interferencebetween them.

A procedure to rapidly determine what is damaged,whether it is repairable, what assets are required,who can perform the repair, and where the repaircan made.

A group of parts which could contain one or moreunrelated parts of a subassembly, one or more sub-assemblies, and attaching hardware.

Related to an axis. Describes the linear distance ashaft or gear moves.

Any incident such as combat damage, random failures,operator errors, accidents, and wear-out failureswhich occur on the battlefield and which prevent theequipment/end item from accomplishing its mission.

A primary structural element designed to carry heavyloads by resisting bending in one direction. Usuallyconstructed with a channel, tee, or “I” cross section.

Any change in an intended configuration.

Inside measurement of the interior diameter of a holeor tube. Also used to describe the hole itself.

GLOS-1

TM 55-1520-228-BDGLOSSARY

GLOSSARY (Cont)

BOWED

BOX BEAM

BRAID

BREAK

BRIDGING

BRINELLED

BULKHEAD

BUCKLE

BURN

BURNISHING

BURR

CANNIBALIZATION

CAP

CATASTROPHIC

CHAFED

CHECK

CHIPPING

CHORDLINE

Curved or gradual deviation from original line or plane.

A primary structural element designed to carry heavyloads by resisting bending in at least two directionscharacterized by a square or rectangular hollow crosssection.

Machine woven wire strands.

Separation of a part or substance from itself.

Jumping or bypassing of a part or component.

Circular indentations on bearing surfaces.

The primary vertical structural element. Often calledframes or walls.

Wrinkle or crease damage to sheet metal structuralelements.

Loss of metal resulting from overheating.

The smoothing of a metal surface by mechanical actionwithout loss of material. Generally found on plainbearing surfaces. Surface discoloration is sometimespresent around outer edges of a burnished area.

A rough edge or sharp projection.

The removal of needed parts or assemblies from otheraircraft, equipment, or from non-essential systemson the helicopter undergoing repair.

A continuous structural element (angle, tee, orchannel shape) fastened to the top and bottom ofa beam or web.

A sudden and disastrous event caused by equipmentfailure which endangers human life.

Functional wear. A rubbing action between two partshaving relative motion.

An examination for verifying.

Breaking away of small metallic particles.

An imaginary line running perpendicular to the leading ortrailing edge of a rotor blade.

GLOS-2


GLOSSARY (Cont)

CLOCKWISE

COATING, PROTECTIVE

COMBAT CAPABLE

COMBAT EMERGENCYCAPABLE

COMPONENT

CONSUMABLE ITEMS

CORE

CORROSION

COUNTER-CLOCKWISE

CRACK

CRIPPLE

CRITERIA

DATA

DECONTAMINATION

DENT

DISASSEMBLY

A circular motion in the direction the hands of a clockrotate when viewed from the front.

An external surface treatment, such as paint, anodizing,electroplating or chemical film, used to delay theeffects of corrosive or atmospheric elements upon metals.

The ability of the helicopter to perform the MINIMUMcombat mission assignments.

The ability of the helicopter to perform LIMITEDspecific tactical mission assignments.

A group of physically connected assemblies or parts.

Parts or materials which are consumed by usage or whichhave a one-time usage in depot maintenance activity.

The inner layer of material used to constructhoneycomb structural panels.

Surface chemical action which results in surfacediscoloration, a layer of oxide, rust, or removal ofsurface metal.

The direction opposite to the direction the hands of aclock rotate, when viewed from the front.

A break in some type of material.

Damage to a load carrying structural member whichwould cause degradation of the helicopters fullmission capability.

Standards or rules used to judge.

A group of facts.

To make an item safe for unprotected personnel byremoving, neutralizing, or destroying any harmfulsubstance. A function of Nuclear, Biological, andChemical (NBC) Warfare.

Indentation in metal surface produced by an objectstriking with force.

The operations necessary to reduce an assembly to itsseparate components and parts.

GLOS-3


GLOSSARY (Cont)

DISTORTION

EROSION

EVACUATION

EXPEDIENT

FAILURE MODE

FATIGUE FAILURE

FIX

FLANGE

A change from an original shape.

Wearing away of metal.

A combat service support function which involves themovement of recovered helicopters from a main supplyroute, maintenance collection point, or maintenanceactivity to higher categories of maintenance.

A rapid and often non-standard method of repairingan item (repair technique).

The specific cause of failure, relating to categoriessuch as cracks, corrosion, ballistic impact, etc.

Sharp indentations, cracks, tool marks, or inclusionsthat result in progressive yielding of one or more localareas of material.

Any rapid action that returns a damaged part orassembly to full or an acceptably degraded operatingcondition (repair technique).

A broad ridge or pair of ridges projecting from theedge of a structural element, providing additionalstrength or a place for attachment.

FLAKING Loose particles of metal or evidence of separation of asurface covering material.

FLUORESCENT PENETRANT A test for locating cracks and fissures in non-magnetic material, making use of radiation propertiesof fluorescent particles when exposed to ultravioletlight.

FORMER

FRACTURE

FRAYING

FULLY MISSIONCAPABLE (FMC)

FUNCTIONAL GROUP

FUSELAGE

A curved structural element which gives the fuselageits even aerodynamic shape. Normally longerons andstringers are attached and the skin is fittedtightly over all these elements.

Separation of a part or piece of material from itself.

Loose or raveled threads and fibers.

The ability of the helicopter to perform ALL its combatmission assignments.

Major helicopter subsystems identified in andcorresponding to functional groups in TM 55-1520-236-23.

The central main body of the helicopter.

GLOS-4


GLOSSARY (Cont)

GALLING

GAP

GOUGING

HEAT DISCOLORATION

HEI

HOUSING

INDENTATION

INSPECTION

INTERFACE

JURY-RIGGING

LIMIT

LOAD PATH

LONGERON

LRU

MAINTENANCE COLLECTIONPOINT

MAINTENANCE SUPPORTTEAM (MST)

Aggravated condition of wear, generally caused by arubbing action with little or no lubrication.

Clearance between faying surfaces, measurement of whichis used to determine thickness of shims.

Removal of surface metal because of mechanical contactwith foreign material.

A change in color or appearance of a part, caused byexcessive temperature.

High explosive incendiary armament round.

A frame support or cover, used to hold parts ofmachinery in place. Also used as a protective cover.

A cavity with smooth bottom or sides, which can occuron rolling contact surfaces.

A critical examination of parts to determine their use-fulness or condition.

The joining point of two flat surfaces.

A rapid non-standard method of repairing an item(repair technique).

An established point or boundary, in time, speed, orspace, beyond which something may not go or is notpermitted to go.

The route taken by a mechanical force traveling throughan airframe structure.

A principle longitudinal (fore and aft), structuralelement (angle or tee shape) continuous across severalpoints of support.

Line replaceable unit (electronic circuit board).

A point operated by AVIM units for the collection ofequipment for repair.

A team consisting of AVUM and AVIM mechanics and technicalspecialist who are trained in assessing battle damage inaddition to their routine speciality.

GLOS-5


GLOSSARY (Cont)

MAINTENANCE TEAM(MT)

MISSION FUNCTIONCOMBAT CAPABLE(MFCC)

MODIFICATION

NATIONAL STOCK NUMBER(NSN)

NICK

OPERATION

OPTION

OVERHAUL

PEELING

PIGTAIL

PITTING

PRACTICE

PRIMARY STRUCTURE

PROCEDURE

PROCESS

PYLON

A team consisting of organizational mechanics who maybe trained in assessing battle damage and field repairprocedures.

The ability of the helicopter to perform the MINIMUMcombat mission assignments.

An alteration and/or integral change affecting theconfiguration of equipment or its respective parts,components, subassemblies, or assemblies.

The assigned identifying number for an item ofsupply, consisting of the four-digit Federal SupplyClass (FSC), and the nine-digit National StockIdentification Number (NIIN).

A local break or notch in the edge of material.

Performance of a practical, functional action.

A specific BDAR repair technique often non-standardin nature.

The process of repairing or adjusting a machine torestore, improve, or lengthen its useful life.

A breaking away of surface finishes such as coatingsor platings, or flaking of large pieces of such material.

A group of electrical wire strands twisted together.

Small holes or indentations, generally caused by rust,corrosion, high compressive stresses, or metal-to-metalpounding.

A repeated or customary action.

The major structural load carrying elements of anairframe without which helicopter flight safety wouldbe compromised.

A particular course of action.

A series of actions conducive to an end.

The box shaped structural area surrounding the helicoptermain transmission. This area carries several primarystructural loads.

GLOS-6


GLOSSARY (Cont)

REASSEMBLY

RECOVERY

REMOVE

REPAIR

REPLACE

REWORK

RUPTURE

SCORING

SCRATCHING

SECONDARY STRUCTURE

SELF-RECOVERY

SEMIMONOCOQUE

SERVICING

SKIN

The assembling and aligning of all subassemblies andparts into a complete assembly to affect a serviceableitem of equipment.

The retrival of immobile, inoperative, or abandonedhelicopters from the battlefield or immediate vicinityand its movement to a maintenance collection point, mainsupply route, or a maintenance activity for disposition,repair, or evacuation.

To move by lifting, pulling or pushing.

To restore a defective part, component, subassembly, orassembly to a usable condition in accordance with theinstructions contained in this manual.

To supply an equivalent for.

To work over again.

The breaking of an airframe structural element or skindue to overstress/hostile fire.

Very deep scratches caused by foreign particles betweensurfaces that are moving, or between one moving andone stationary surface. Scores follow the traveldirection of the part.

Narrow, shallow lines resulting from movement offoreign particles across a surface.

The non-flight safety structural elements of an airframe.

The ability of the helicopter to fly at reduced airspeedand altitude from the battlefield or immediate vicinityto a maintenance collection point, the main supply route,or maintenance activity for disposition, repair orevacuation.

A structural design which relies on strength of the skinto carry a large portion of the load. The skin is nor-mally reinforced by longerons and vertical bulkheads(walls), but has no diagonal bracing, leaving the interiorbasicly hollow.

The lubrication, treating, cleaning, or preservationnecessary to maintain the equipment and other respectiveparts in serviceable condition.

The aerodynamic exterior covering of the helicopter.

GLOS-7


GLOSSARY (Cont)

SPALLING

SPANWISE

SPAR

STIFFENER

STOP HOLE

STRINGER

TEST

TOLERANCE

TOXIC

TWIST

VISCOSITY

WARPAGE

WEB

WHIP

Chipped or flaked surface caused by the breaking away ofthe hardened metal and separation of the case from thecore.

The location of a point or direction of movement parallelto the leading or trailing edge of a rotor blade.

A primary structural element designed to carry weightand resist bending loads in wings and rotor blades.Spars typically extend the full length of the wing, andtaper down to a smaller cross section toward the tipof the wing.

A longitudinal (fore and aft) structural element use insemimonocoque design which stiffens the skin. Oftencalled a stringer.

A hole intentionally drilled at the end of a crack, or sawcut which normally will prevent further propagationof the crack.

A longitudinal (fore and aft) structural element used insemimonocoque design which stiffens the skin. Oftencalled a stiffener.

As used herein, the checking or operation of equipmentto determine that the unit functions properly within thelimits set forth in this manual.

The difference between two limiting sizes as ameans of specifying the degree of accuracy.

A poisonous substance.

The damage of a structural element by turning or torqueforces causing permanent deformation.

The property of a fluid that tends to resist the forcetrying to make it flow such as gravity or appliedpressure.

The bending or twisting damage causing a structuralelement to weaken and permanently loose its originalshape.

The sheet metal membrain connecting the upper and lowerflanges of a beam or spar. Provides overall rigidity tothe airframe structure.

The tendency of a bent shaft to rotate away from itsoriginal center as the shaft RPM is increased, thuscausing severe vibration.

GLOS-8

TM 55-1520-228-BD

By Order of the Secretary of the Army

Official:

CARL E. VUONOGeneral, United States Army

Chief of Staff

THOMAS F. SIKORABrigadier General, United States Army

The Adjutant General

DISTRIBUTION:To be distributed in accordance with DA Form 12-31, AVUM and AVIM Maintenance

requirements for OH-58A and OH-58C Helicopter Observation.

*U.S.GOVERNMENT PRINTING OFFICE: 1991554-122/21097

These are the instructions for sending an electronic 2028The following format must be used if submitting an electronic 2028. The subject line must beexactly the same and all fields must be included; however only the following fields aremandatory: 1, 3, 4, 5, 6, 7, 8, 9, 10, 13, 15, 16, 17, and 27.

From: “Whomever” <[email protected]>To: [email protected]

Subject: DA Form 20281. From: Joe Smith2. Unit: home3. Address: 4300 Park4. City: Hometown5. St: MO6. Zip: 777777. Date Sent: 19--OCT--938. Pub no: 55--2840--229--239. Pub Title: TM10. Publication Date: 04--JUL--8511. Change Number: 712. Submitter Rank: MSG13. Submitter FName: Joe14. Submitter MName: T15. Submitter LName: Smith16. Submitter Phone: 123--123--123417. Problem: 118. Page: 219. Paragraph: 320. Line: 421. NSN: 522. Reference: 623. Figure: 724. Table: 825. Item: 926. Total: 12327. Text:This is the text for the problem below line 27.

RECOMMENDED CHANGES TO PUBLICATIONS AND

BLANK FORMSFor use of this form, see AR 25--30; the proponent agency is ODISC4.

Use Part II (reverse) for Repair Parts and Spe-cial Tool Lists (RPSTL) and Supply Catalogs/Supply Manuals (SC/SM)

DATE

8/30/02

TO: (Forward to proponent of publication or form)(Include ZIP Code)

Commander, U.S. Army Aviation and Missile Command

ATTN: AMSAM--MMC--MA--NP

R eds t one A r s enal, AL. 35898

FROM: (Activity and location)(Include ZIP Code)

MSG, Jane Q. Doe

1234 Any Street

Nowhere Town, AL 34565

PART 1 -- ALL PUBLICATIONS (EXCEPT RPSTL AND SC/SM) AND BLANK FORMS

PUBLICATION/FORM NUMBER

TM 9--1005--433--24DATE

16 Sep 2002TITLE Organizational, Direct Support, And GeneralSupport Maintenance Manual for Machine Gun, .50Caliber M3P and M3P Machine Gun Electrical Test SetUsed On Avenger Air Defense Weapon System

ITEM

NO.

PAGE

NO.

PARA--

GRAPH

LINE

NO. *

FIGURE

NO.

TABLE

NO.RECOMMENDED CHANGES AND REASON

1 WP0005

PG 3

2 Test or Corrective Action column should identify a different WP number.

* Reference to line numbers within the paragraph or subparagraph.

TYPED NAME, GRADE OR TITLE

MSG, Jane Q. Doe, SFC

TELEPHONE EXCHANGE/AUTOVON, PLUS EXTEN-SION

788--1234

SIGNATURE

DA FORM 2028, FEB 74 REPLACES DA FORM 2028, 1 DEC 68, WHICH WILL BE USED. USAPA V3.01

TO: (Forward direct to addressee listed in publication)

Commander, U.S. Army Aviation and Missile Command

ATTN: AMSAM--MMC--MA--NP

R eds t one A r s enal, AL. 35898

FROM: (Activity and location) (Include ZIP Code)

MSG, Jane Q. Doe

1234 Any Street

Nowhere Town, AL 34565

DATE

8/30/02

PART II -- REPAIR PARTS AND SPECIAL TOOL LISTS AND SUPPLY CATALOGS/SUPPLY MANUALS

PUBLICATION NUMBER DATE TITLE

PAGE

NO.

COLM

NO.

LINE

NO.

NATIONAL STOCK

NUMBER

REFERENCE

NO.

FIGURE

NO.

ITEM

NO.

TOTAL NO.OF MAJOR

ITEMSSUPPORTED

RECOMMENDED ACTION

PART III -- REMARKS (Any general remarks or recommendations, or suggestions for improvement of publications and

blank forms. Additional blank sheets may be used if more space is needed.)

TYPED NAME, GRADE OR TITLE

MSG, Jane Q. Doe, SFC

TELEPHONE EXCHANGE/AUTOVON,PLUS EXTENSION

788--1234

SIGNATURE

USAPA V3.01

RECOMMENDED CHANGES TO PUBLICATIONS AND

BLANK FORMSFor use of this form, see AR 25--30; the proponent agency is ODISC4.

Use Part II (reverse) for Repair Parts and Spe-cial Tool Lists (RPSTL) and Supply Catalogs/Supply Manuals (SC/SM)

DATE

TO: (Forward to proponent of publication or form)(Include ZIP Code) FROM: (Activity and location)(Include ZIP Code)

PART 1 -- ALL PUBLICATIONS (EXCEPT RPSTL AND SC/SM) AND BLANK FORMS

PU BLIC ATIO N /FO R M N U MBER DATE T I T LE

ITEM

NO.

PAGE

NO.

PARA--

GRAPH

LINE

NO. *

FIGURE

NO.

TABLE

NO.RECOMMENDED CHANGES AND REASON

* Reference to line numbers within the paragraph or subparagraph.

TYPED NAME, GRADE OR TITLE TELEPHONE EXCHANGE/AUTOVON, PLUS EXTEN-SION

SIGNATURE

DA FORM 2028, FEB 74 REPLACES DA FORM 2028, 1 DEC 68, WHICH WILL BE USED. USAPA V3.01

Commander, U.S. Army Aviation and Missile CommandATTN: AMSAM-MMC-MA-NPRedstone Arsenal, AL. 35898

4 Jan 1991 Technical Manual Operators, Aviation and IntermediateMaintenance Battlefield Damage Assessment and Repair

TM 55-2840-228-BD

for Helicopter, Observation OH-58A & OH-58C

TO: (Forward direct to addressee listed in publication) FROM: (Activity and location) (Include ZIP Code) DATE

PART II -- REPAIR PARTS AND SPECIAL TOOL LISTS AND SUPPLY CATALOGS/SUPPLY MANUALS

PUBLICATION NUMBER DATE TITLE Technical Manual Operators, Aviation and Inter-

PAGE

NO.

COLM

NO.

LINE

NO.

NATIONAL STOCK

NUMBER

REFERENCE

NO.

FIGURE

NO.

ITEM

NO.

TOTAL NO.OF MAJOR

ITEMSSUPPORTED

RECOMMENDED ACTIO N

PART III -- REMARKS (Any general remarks or recommendations, or suggestions for improvement of publications and

blank forms. Additional blank sheets may be used if more space is needed.)

TYPED NAME, GRADE OR TITLE TELEPHONE EXCHANGE/AUTOVON,PLUS EXTENSION

SIGNATURE

USAPA V3.01

Commander, U.S. Army Aviation and Missile CommandATTN: AMSAM-MMC-MA-NPRedstone Arsenal, AL 35898

TM 55-2840-228-BD 4 Jan 1991and Repair for Helicopter, Obsevation OH-58A & OH-58Cmediate Maintenance Battlefield Damage Assessment

The Metric System and Equivalents

Linear Measure

1 centimeter = 10 millimeters = .39 inch1 decimeter = 10 centimeter = 3.94 inches1 meter = 10 decimeters = 39.37 inches1 dekameter = 10 meters = 32.8 feet1 hectometer = 10 dekameters = 328.08 feet1 kilometer = 10 hectometers = 3,280.8 feet

1 centiliter = 10 milliters = .34 fl. ounce1 deciliter = 10 centiliters = 3.38 fl. ounces1 liter = 10 deciliters = 33.81 fl. ounces1 dekaliter = 10 liters = 2.64 gallons1 hectoliter = 10 dekaliters = 26.42 gallons1 kiloliter = 10 hectolitas = 264.18 gallons

1 centigram = 10 milligrams = .15 grain1 decigram = 10 centigrams = 1.54 grains1 gram = 10 decigram = .035 ounce1 dekagram = 10 grams = .35 ounce1 hectogram = 10 dekagrams = 3.52 ounces1 kilogram = 10 hectograms = 2.2 pounds1 quintal = 100 kilograms = 220.46 pounds1 metric ton = 10 quintals = 1.1 short tons

1 sq. centimeter = 100 sq. millimeters = .155 sq. inch1 sq. decimeter = 100 sq. centimeters = 15.5 sq. inches1 sq. meter (centare) = 100 sq. decimeters = 10.76 sq. feet1 sq. dekameter (are) = 100 sq. meters = 1,076.4 sq. feet1 sq. hectometer (hectare) = 100 sq. dekameters = 2.47 acres1 sq. kilometer = 100 sq. hectometers = .386 sq. mile

inchesfeetyardsmilessquare inchessquare feetsquare yardssquare milesacrescubic feetcubic yardsfluid ouncespintsquartsgallonsouncespoundsshort tonspound-feetpound-inches

To

1 cu. centimeter = 1000 cu. millimeters = .06 cu. inch1 cu. decimeter = 1000 cu. centimeters = 61.02 cu. inches1 cu. meter = 1000 cu. decimeters = 35.31 cu. feet

Approximate Conversion Factors

centimetersmetersmeterskilometerssquare centimeterssquare meters

square meterssquare kilometerssquare hectometerscubic meterscubic metersmilliliterslitersliterslitersgramskilogramsmetric tonsnewton-metersnewton-meters

oF Fahrenhei ttemperature

Multiply by

2.540.305.914

1.6096.451

.093

.8362.590

.405

.028

.76529,573

.473

.9463.785

28.349.454.907

1.356.11296

To change

ounce-inchescentimetersmetersmeterskilometerssquare centimeterssquare meterssquare meterssquare kilometerssquare hectometerscubic meterscubic metersmilliliterslitersliterslitersgramskilogramsmetric tons

Temperature (Exact)

5/9 (after Celsius oCsubtracting 32) temperature

To

newton-metersinchesfeetyardsmilessquare inchessquare feetsquare yardssquare milesacrescubic feetcubic yardsfluid ouncespintsquartsgallonsouncespoundsshort tons

Multiply by

.007062.394

3.2801.094

.621

.15510.764

1.196.386

2.47135.315

1.308.034

2.1131.057

.264

.0352.2051.102

Weights

Liquid Measure

Square Measure

Cubic Measure

To change

P I N : 0 6 6 6 3 5 - 0 0 0

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TM 55-1520-228-BD TECHNICAL MANUAL OPERATORS, …tm 55-1520-228-bd technical manual operators, aviation unit, and aviation intermediate maintenance for hellcopter, observation oh-58a