Csl 1080

7/29/2019 Csl 1080

1/4

hllison GAS TURf3lNE DIVISION

FAA ApprovedI SUBJECT: MODEL 250/225 FUEL SYSTE M - OPERATION AND MAINTENANCE GUIDELINES

IThe purpose of this CSL is to provide a summary of operational and maintenanceguidelines for the Model 250/225 engine fuel system. it is advisab le that bothpilots and maintenance personnel utilize this information .to best preventproblems such as flameouts and power losses from occurr ing and to providereliable fuel system service. Some of the information in this CSL may be m.Please read it completely.

1.

2.

3.

I 4.

5.

6.

The engine demands clean, dry fuel. Refer to FAA Advisory Circular No.00-34, "Aircraft Ground Handling and Servicing" , paragraph 8, "AircraftFueling" for important tips on fuel handling.The aircraft fuel tanks and related system must be clean. Maintain andclean the fuel tanks and lines according to the instruc tions in the airframemaintenance manual. Drain the fuel tank sump daily in accordance with theaircraft flight manual.All fuel lines must be properly torqued as specified in the Engine andAirframe Maintenance Manual. It is possib le to have a leak in a fuel line,anywhere from the fuel pickup in the tank to the engine driven pump inlet.This leak may "suck" air but won't necessarily leak fuel. A continuous airleak or a single slug of air can cause a flameout.If the aircraft flight manual requires operation with the boost pumps orstart pump 'on", then they must be "on". This w ill not only ensure a properhead of pressure to the inlet of engine driven fuel pump, but wil l reducethe probability of "sucking" air thru a tiny fuel line leak.The uncovering of a fuel boost pump or the fuel inlet fitting in the tank,due to a low fuel leve l and/or flight maneuver, can result in a slug of airentering the engine fuel system.All pneumatic lines, double check valves, and accumulato,rs must be properlytorqued with special care to avoid any twists that may develop cracks lateron. A leak in the pneumatic section can cause erratic operation, powerloss, or a flameout.

May 11, 1979Revision No. 2November 1, I988

250.Cl8 Series CSL 149250-C20 Series csc 1080250-C28 Series CSL 2092250-C30 Series CSL 30952%CZOR Series CSL 4013225-Cl0 Series CSL 5008250-815 Series TP CSL 83250-817 Series TP CSL 1103250-B17F Series TP CSL 2006Page 1 of 4

Rolls-Royce Proprietary Data Uncontrolled Printed Copy

7/29/2019 Csl 1080

2/4

ALLISON GAS TURBINECommercial Service Letter

I

7. If the aircraft has an engine fuel filter differential pressure warningsystem, it must be checked periodically for proper operation. Depressingthe caution light in the cockpit in most installations only confirms thatthe light bulb is functional, hence, a functional check of the total systemis necessary . Refer to the aircraft maintenance manual for instructions.Also , ensure that all connections in the system are tightened properly.Some Model 250/225 engine fuel systems also incorporate a low pressure fuelfilter equipped with an impending by-pass button. This impending by-passindicator is to be monitored per the appropriate engine maintenance manual.

8. The engine driven fuel pump filter or low pressure fuel filter, depending onengine model, are not cleanable. Consult the appropriate engine maintenancemanual for filter replacement criteria or retirement schedule.CAUTION: Some operators have inadvertently installed the old ten micron low

pressure fuel filter (P/N AN62353A) in place of the recommendedfive micron filter (P/N 6895177). This is a critical item,especially for those engines utilizing CECO fuel systems. Pleaseinspect your engine and spare stock to ensure the correct filteris installed.

9. The engine fuel pump wil l not pump fuel with a sheared spline.Certain Series I/II Sundstrand fuel pumps require replacement of the driveshaft and gear set before further operation. Consult the following CEBs fordetails:

250-Cl8 CEB 208250-c20 CEB 1164250-B15 TP CEB 78250-B17 TP CEB 1137

10. On Series II engines so equipped, if the low pressure fuel fi lter hasbypassed, the CECO control and governor should be flushed per Alli sonCSL-1034 and CSL-1035.

11. Alli son 250-C20 CEB-1095 recommends installation of a high pressure fuelfilter assemb ly if the engine is equipped with a CECO system. If you havea Series II engine equipped with the CECO system and don't have the highpressure fuel filter, please get one.

May 11, 1979Revision No. 2November 1, 1988

250-Cl8 Series CSL 149Z50-C20 Series CSL 1080250.C28 Series CSL 2092250-C30 Series CSL 3095250.C20R Series CSL 4013225-Cl0 Series CSL 5008250-815 Series TP CSL 83250-817 Series TP CSL 1103250.B17F Series TP CSL 2006

Page 2Rolls-Royce Proprietary Data Uncontrolled Printed Copy

7/29/2019 Csl 1080

3/4

ALLISON GAS TURBINECommercial Service Letter

12. The high pressure fuel filter has done a tremendous job in reducing thenumber of .incidents resultina from contaminated CECO controls andgovernors. Now that the filter has been in service fo'r several years, itis evident that additional maintenance is necessary . ALLISON NOWRECOMMENDS THAT THE HIGH PRESSURE FUEL FILTER ELEMENT 13E REPLACED WITH ANEW OR THOROUGHLY CLEAN ELEMENT AND THAT THE BY-PAS S VALVE BE INSPECTED FORWEAR EVERY 100 HOURS. See the currently published Series II Operation andMaintenance Manual for inspection criteria.

13. Recent information provided to Alli son revealed that ultrasonic cleaning ofCeco system high pressure filter may not provide the best removal ofimbedded contaminates. Therefore, the following procedure is recommendedas a primary and/or additional method.a. Fil l the inside of the filter with a clean liquid biodegradable,

undiluted, dishwashing detergent, such as Joy, Ivory, Palmolive, Dove,Dawn, Dermassage, Amway L.O.C., etc. Immerse into a container ofundiluted detergent.

b. Let the detergent soak for a minimum of 5 minutes. Then remove fromcontainer.

C . Apply filtered shop air to the inside of the filter thru the opening inthe end cap, forcing detergent out via convolution/pleats. Repeatapplication of detergent.

d. Run hot clean water into the inside of the filter thru the hole, untilthe water runs clear of soap bubbles and contaminates. The more effortexpended will result in a cleaner filter element.

e. Remove excess moisture.14. Duick check for cleanliness of the CECO high pressure Filter Element.

CAUTION: Be aware of the potential fire hazard when using the belowprocedure.

a. Fi ll a flat bottom container with fuel or Stoddard solvent, atapproximately room temperature, to 1 3/4 + l/16 inch deep. This i s alevel which wil l cover the convolutions/pleats; but does not reach thecenter opening with the element standing upright-open end on top.


250-Cl8 Series CSL 149250-C20 Series CSL 1080250-C28 Series CSL 2092250.C30 Series CSL 3095250-C20R Seri'es CSL 4013225-Cl0 Series CSL 5008250-815 Series TP CSL 83250-817 Series TP CSL 1103250.B17F Series TP CSL 2006Page 3


7/29/2019 Csl 1080

4/4

ALLISON GAS TURBINECommercial Service Letterb. Thoroughly wet the filter element media with fuel or Stoddard solvent

to reduce surface tension. This can be accomplished by forcing theliquid through the element utilizing a 3/8 inch outside diameter tubein the element opening and forcing fuel thru.Pour out any liquid from the inside and immerse the element in theabove container.Determine the time it takes for the fluid to rise inside the element tothe level of the surrounding liquid.If cleaned sufficien tly, the element should fill within 5 seconds.Repeat cleaning procedures if necessary. If unable to meet the 5second limit , replace the element with one that meets the 5 secondlimit.

15. The pneumatic (air) circuit of the Bendix System will accumulate dirtduring normal operation. The Troubleshooting section of the appropriateOperation and Maintenance Manual curren tly lists troubles that can becorrected by cleaning the Bendix air circuit.

16. The Allis on Series I/II Turboshaft Operation and Maintenance Manualsrecommend a postflight deceleration check of the Bendix system. Allison250.C20 CSL-1047 recommends a daily deceleration check for the CECOsystem. These deceleration checks are a good method to uncover impendingproblems. ALLISON RECOMMENDS THAT A POSTFLIGHT DECELERATION CHEC K BECONDUCTED ON BOTH THE BENDIX AND CECO SYSTEMS.

17. Rigging to the fuel control and governor is very important. Don't overlookthe aircraft and engine manual requirements. Wear in the linkages cansneak up on you and cause a flameout.

18. Go over the above list again. If there is something you don't understand,please ask questions. The reliable operation of your engine is yourresponsibility.


PRODUCT SUPPORTAllison Engine Company

250-Cl8 Series L>L 149250-C20 Series CSL 1080250-C28 Series CSL 2092250-C30 Series CSL 3095250.C20R Series CSL 4013225-Cl0 Series CSL 5008250.B15 Series TP CSL 83250-B17 Series TP CSL 1103250.B17F Series TP CSL 2006

Page 4


Documents

Csl 1080