KEMENTERIAN PERHUBUNGAN

DIREKTORAT JENDERAL PERHUBUNGAN UDARA

Jalan Merdeka Barat No. 8

Jakarta 10110

Kotak Pos No. 1389

Jakarta 10013

Telepon : 3505550 - 3505006(Sentral)

Fax:3505136-3505139

3507144

PERATURAN DIREKTUR JENDERAL PERHUBUNGAN UDARA

NOMOR : KP 012 tahun 2012

TENTANG

PETUNJUK DAN TATA CARA BAGIAN 120 - CSEA 001 (ADVISORY CIRCULARPART 120-CSEA 001) PANDUAN BAGI OPERATOR UNTUK PROGRAM PELATIHAN

PENGGUNAAN SISTEM PERINGATAN DAN SITUASI TERHADAP DARATAN

(GUIDANCE FOR OPERATORS ON TRAINING PROGRAMMES FOR THE USEOF TERRAIN AWARENESS AND WARNING SYSTEM)

DENGAN RAHMAT TUHAN YANG MAHA ESA

DIREKTUR JENDERAL PERHUBUNGAN UDARA,

Menimbang : a. bahwa dalam rangka menjamin keselamatan penerbangan danmengantisipasi perkembangan teknologi penerbangan, perlu dibuatpenyeragaman panduan bagi operator untuk program pelatihanpenggunaan sistem peringatan dan situasi terhadap daratan;

b. bahwa berdasarkan pertimbangan sebagaimana dimaksud padahuruf a, perlu mengatur Petunjuk dan Tata Cara Bagian 120- CSEA00'\(Advisory Circular Part 120-CSEA 001) Panduan Bagi OperatorUntuk Program Pelatihan Penggunaan Sistem Peringatan dan Situasiterhadap Daratan (Guidance For Operators On Training ProgrammesFor The Use Terrain Awareness and Warning System), denganPeraturan Direktur Jenderal Perhubungan Udara;

Mengingat : 1. Undang-Undang Nomor 1 Tahun 2009 tentang Penerbangan(Lembaran Negara Republik Indonesia Tahun 2009 Nomor 1,Tambahan Lembaran Negara Republik Indonesia Nomor 4956);

2. Peraturan Pemerintah Nomor 3 Tahun 2001 tentang Keamanan danKeselamatan Penerbangan (Lembaran Negara Tahun 2001 Nomor 9,Tambahan Lembaran Negara Nomor 4075);

3. Peraturan Presiden Nomor 47 Tahun 2009 tentang Pembentukandan Organisasi Kementerian Negara sebagaimana diubah terakhirdengan Peraturan Presiden Nomor 91 Tahun 2011;

1. PURPOSE

2. REFERENCE

3. CANCELATION

4. AMENDMENT

FOREWORD

This advisory circular (AC) provides information and guidancefor Operators to prepare performance-based trainingobjectives for Terrain Awareness and Warning System(TAWS) pilot training.

Amendment of this Advisory Circular should be approved byDirector General of Civil Aviation.

DIRECTOR GENERAL OF CIVIL AVIATION,

ttd

HERRY BAKTI

Salinan sesuai dengan aslinya

KEPALA BAGJAN HUKUM DAN HUMAS

ISRAFULHAYATPembina (IV/a)

NIP. 19680619 199403 1 002

TABLE OF CONTENTS

FOREWORD II

TABLE OF CONTENTS Ill

CHAPTER 1 -GENERAL 1-1

1. PURPOSE 1-12. RELATED REGULATIONS 1-13. APPLICABILITY 1-14. BACKGROUND |-2

5. SCOPE |-3

CHAPTER 2 - PERFORMANCE BASED TRAINING OBJECTIVES 11-1

1. TAWS ACADEMIC TRAINING 11-1

2. TAWS MANEUVER TRAINING II-73. TAWS INITIAL EVALUATION II-94. TAWS RECURRENT TRAINING (ANNUAL) II-9

CHAPTER 3 - REPORTING PROCEDURES 111-1

1. VERBAL REPORTS HI-12. WRITTEN REPORTS HI-1

in

CHAPTER 1

GENERAL

PURPOSE

a. This advisory circular (AC) contains performance-based trainingobjectives for Terrain Awareness and Warning System (TAWS) pilottraining.

b. The training objectives cover five areas:

1) theory of operation;2) pre-flight operations;3) general in-flight operations;4) response to TAWS cautions; and5) response to TAWS Warnings.

c. The term TAWS' in this AC means a Ground Proximity WarningSystem (GPWS) enhanced by a forward looking terrain avoidancefunction. 'Alerts' include both 'cautions' and 'warnings'.

d. The contents of this AC are intended to assist operators who arerequired to develop and conduct training programmes. Theinformation it contains has not been tailored to any specificaeroplane or TAWS equipment, but highlights features typicallyavailable where such systems are installed. It is the responsibility ofeach individual operator to determine the applicability of thecontents of this AC to each aeroplane and TAWS equipmentinstalled, and their operation. Operators should refer to theirAeroplane Flight Manual and/or Aeroplane/Flight Crew OperatingManual for information applicable to specific configurations. If thereshould be any conflict between the contents of this AC and thosepublished in the other documents described above, then informationcontained in the AFM or A/FCOM will take precedence over thatcontained in this AC.

2. RELATED REGULATIONS

CASR Part 121.360 & CASR Part 135.319

3. APPLICABILITY

All Operators who are required to operate aeroplanes equipped with TAWSas per the requirements of the Civil Aviation Safety Regulations mustensure the flight crew are provided the minimum training and followprocedures as stipulated in this AC. The Operator is required to maintain

Chapter I j3j*

relevant records of all ground and simulator training provided to the flightcrew for perusal by the DGCA as and when required.

BACKGROUND

a. The introduction of ground proximity warning system (GPWS)equipment in 1978 resulted in a significant reduction in controlledflight into terrain (CFIT) accidents. However, CFIT accidents do stilloccur, not only to those aeroplanes that have no GPWS, but also toGPWS-equipped aeroplanes that encounter terrain rising too rapidlyahead of them or that descend below a safe approach path when ina landing configuration. It was with these shortcomings in mind thatavionics manufacturers developed a solution to which theInternational Civil Aviation Organization (ICAO) responded bypublishing Standards and Recommendations concerning retrofitaction it believes can or should be taken.

b. GPWS feeds inputs to its computer from a downwards-looking radioaltimeter, an air data computer, an instrument landing system (ILS)glide slope signal, and flap and gear selector lever positions: itsoutputs include visual and aural alerts and warnings when it detectsby rate-of-change of position that the aircraft is closing with terrain.To satisfy the ICAO requirement that GPWS should now include apredictive terrain hazard warning function, a terrain awareness andwarning system has recently been developed. The predictivefunction is achieved by feeding the aeroplane's known position (asdetermined by a flight management system (FMS) or by a globalpositioning system (GPS)) to a terrain data base, enabling thecomputer to predict terrain ahead and to the side of the aeroplane'sflight path. Terrain features can then be displayed to the flight crew.TAW therefore overcomes shortcomings associated with GPWS inthat it produces earlier alerts and warnings of significant terrain thatlie ahead at all stages of flight. Furthermore, with reference to terrainaround airfields, it can warn of descent below safe vertical profileswhen the aircraft is in a landing configuration and there is no ILSglideslope signal present. Pilots' situational awareness is greatlyimproved by means of terrain features displayed before them. Thisdisplayed information, related to flight path and altitude, means thatthe alerting and warning capabilities TAWS possesses are lesslikely to be needed than if GPWS alone were installed (Note- theacronym EGPWS (Enhanced GPWS) that has been in use for sometime describes only one TAWS solution - other solutions are now inthe course ofdevelopment or in production.)

SCOPE

a. The scope of this AC is designed to identify training objectives in theareas of: academic training; maneuver training; initial evaluation;and recurrent qualification. Under each of these four areas, the

Chapter I

training material has been separated into those items which areconsidered essential training items and those which are considereddesirable. In each area, objectives and acceptable performancecriteria are defined.

No attempt is made to define how the training programme should beimplemented. Instead, objectives are established that define theknowledge a pilot operating TAWS is expected to possess and theperformance expected from a pilot who has completed TAWStraining. However, the guidelines do indicate those areas in whichthe pilot receiving the training should demonstrate his/herunderstanding, or performance, using a real-time, interactive trainingdevice, ie a flight simulator. Where appropriate, notes are includedwithin the performance criteria which amplify or clarify the materialaddressed by the training objective.

Chapter I 1-3

CHAPTER 2

PERFORMANCE BASED

TRAINING OBJECTIVES

1. TAWS ACADEMIC TRAINING

This training is typically conducted in a classroom environment. Theknowledge demonstrations specified in this section may be completedthrough the successful completion of written tests or by providing correctresponses to non real-time computer based training (CBT) questions.

a. Theory of operation

The pilot should demonstrate an understanding of TAWS operationand the criteria used for issuing cautions and warnings. This trainingshould address the following topics:

1) System Operation

Objective: To demonstrate knowledge of how TAWS functions.

Criteria: The pilot must demonstrate an understanding of thefollowing functions:

(i) Surveillance

• The GPWS computer processes data supplied froman air data computer, a radio altimeter, anILS/MLS/MM (multi-mode) receiver, a roll attitudesensor, and flap and gear selector position sensors.

• The forward looking terrain avoidance functionutilizes an accurate source of known aircraftposition, such as may be provided by a flightmanagement system (FMS) or global positioningsystem (GPS), and an electronic terrain database.The source and scope of the terrain, obstacle andairport data, and features such as the terrainclearance floor, the runway picker, and geometricaltitude (where provided) should all be described.

• Displays required to deliver TAWS outputs include aloudspeaker for voice announcements, visual alerts(typically amber and red lights), and a terrainawareness display (that may be combined with otherdisplays). In addition, means must be provided forindicating the status of TAWS and any partial ortotal failures that may occur.

Chapter II 11-1

(ii) Terrain Avoidance

• Outputs from the TAWS computer provide visualand audio synthetic voice cautions and warnings toalert the flight crew about potential conflicts withterrain and obstacles.

2) Alert Thresholds

Objective: To demonstrate knowledge of the criteria for issuingcautions and warnings.

Criteria: The pilot should be able to demonstrate anunderstanding of the methodology used by TAWS toissue cautions and alerts and the general criteria for theissuance of these alerts t o include:

• Basic GPWS alerting modes specified in the ICAOStandard:

•

Mode 1

Mode 2

Mode 3

Mode 4

Mode 5

excessive sink rate;excessive terrain closure rate:

descent after take-off or go-around;unsafe proximity t o terrain;descent below ILS glide slope (cautiononly).

An additional, optional alert mode:

Mode 6: radio altitude call-out (information only).

• TAWS cautions and warnings that alert the flightcrew to obstacles and terrain ahead of the aircraft in

line with or adjacent to its projected flight path(forward looking terrain avoidance (FLTA) andpremature descent alert (PDA) functions).

3) TAWS Limitations

Objective: To verify that the pilot is aware of the limitations ofTAWS.

Criteria: The pilot should demonstrate a knowledge andunderstanding of TAWS limitations identified by themanufacturer for the equipment model installed. Itemsmight include:

• Navigation is not to be predicated on the use of theterrain display.

Chapter II ||-2

4) TAWS Inhibits

Unless geometric altitude data is provided, use ofpredictive TAWS functions is prohibited whenaltimeter subscale settings display QFE.

Nuisance alerts can be issued if the aerodrome ofintended landing is not included in the TAWS airportdatabase.

In cold weather operations, corrective proceduresshould be implemented by the crew unless TAWShas in-built compensation such as geometric altitudedata.

Loss of input data to the TAWS computer couldresult in partial or total loss of functionality. Wheremeans exist to inform the crew that functionality hasbeen degraded, this should be known and theconsequences understood.

Radio signals not associated with the intended flightprofile (eg ILS glide path transmissions from anadjacent runway) may cause false alerts.

Inaccurate or low accuracy aircraft position datacould lead to false or non annunciation of terrain orobstacles ahead of the aircraft.

MEL restrictions should be applied in the event thatTAWS becomes partially or completelyunserviceable. (It should be noted that basic GPWShas no forward-looking capability).

Objective: To verify that the pilot is aware of the conditions underwhich certain functions of TAWS are inhibited.

Criteria: The pilot should demonstrate knowledge andunderstanding of the various TAWS inhibits including:

• A means of silencing voice alerts;

• A means of inhibiting ILS glide path signals (as maybe required when executing a ILS back beamapproach);

Chapter II jjT"

• A means of inhibiting flap position sensors (as maybe required when executing an approach with theflaps not in a normal position for landing);

• A means for inhibiting the FLTA and PDA functions;

• A means for selecting or deselecting the display ofterrain information;

• Together with appropriate annunciation of the statusof each selection.

b. Operating Procedures

The pilot should demonstrate the knowledge required to operate theTAWS avionics and interpret the information presented by TAWS. Thistraining should address the following topics:

1) Use of controls

Objective: To verify that the pilot can properly operate all TAWScontrols and inhibits.

Criteria: Demonstrate the proper use of controls including:

• The means by which, before flight, any equipmentself-test functions can be initiated

• The means by which TAWS information can beselected for display;

• The means by which all TAWS inhibits can beoperated and what the consequent annunciationmean with regard to loss of functionality.

2) Display Interpretation

Objective: To verify that a pilot understands the meaning of allinformation that can be annunciated or displayed byTAWS.

Criteria: The pilot should demonstrate the ability to properlyinterpret information annunciated or displayed by TAWSincluding:

Chapter II H_4

Chapter II

• Knowledge of all visual and aural indications thatmay be seen or heard;

• Response required on receipt of a caution;

• Response required on receipt of a warning;

• Response required on receipt that partial or totalfailure of TAWS has occurred (includingannunciation that the present aircraft position is oflow accuracy).

3) Use of Basic GPWS or Use of the Forward Looking TerrainAvoidance Function Only.

Objective: To verify that a pilot understands what functionality willremain following loss of the GPWS or of the forwardlooking terrain avoidance function.

Criteria: The pilot should demonstrate knowledge of thefollowing:

• How to recognize uncommanded loss of the GPWSfunction, or how to isolate this function, and whatlevel of CFIT protection then remains (essentially,the forward looking terrain avoidance function).

• How to recognize uncommanded loss of the forwardlooking terrain avoidance function, or how to isolatethis function, and what level of CFIT protection thenremains (essentially, basic GPWS).

4) Crew Co-ordination

Objective: To verify that the pilot adequately briefs other crewmembers on how TAWS alerts will be handled.

Criteria: The pilot should demonstrate that the pre-flight briefingaddresses procedures that will be used in preparationfor responding to TAWS cautions and warningsincluding:

• What action will be taken, and by whom, in the eventthat a TAWS caution and/or warning is issued.

• How multi-function displays will be used to depictTAWS information at take-off, in the cruise, and forthe descent, approach, landing (and any go-around).

(This will be in accordance with procedures specifiedby the operator, who will recognize both that it maybe more desirable that other data is displayed a tcertain phases of flight, and that the terrain displayhas an automatic 'pop-up' mode in the event that analert is issued.)

5) Reporting Requirements

Objective: To verify that the pilot is aware of the requirements forreporting alerts to the controller and other authorities.

Criteria: The pilot should demonstrate the following:

• When, following recovery from a TAWS alert orcaution, any transmission of information should bemade to the appropriate air traffic control unit;

• What written report is required to be made, how it isto be made, and whether any cross- referenceshould be made in the aircraft technical log and/orvoyage report (in accordance with proceduresspecified by the operator) following a flight in whichthe aircraft flight path has been modified in responseto a TAWS alert, or if any part of the equipmentappears not to have functioned correctly.

6) Alert Thresholds

Objective: To demonstrate knowledge of the criteria for issuingcautions and warnings.

Criteria: The pilot should be able to demonstrate an understandingof the methodology used by TAWS to issue cautions andwarnings and the general criteria for the issuance of thesealerts to include:

•

•

Awareness of the modes associated with basicGPWS including the input data associated witheach.

Awareness of the visual and aural annunciationsthat can be issued by TAWS, and how to identifywhich are cautions and which are warnings.

Chapter II H_6

4. Peraturan Presiden Nomor 24 Tahun 2010 tentang Kedudukan, Tugasdan Fungsi Kementerian Negara serta Susunan Organisasi, Tugas danFungsi Eselon Kementerian Negara sebagaimana dibah terakhirdengan Peraturan Presiden Nomor 92 Tahun 2011;

5 Keputusan Menteri Perhubungan Nomor T.11./2/4-U Tahun 1960tentang Peraturan Peraturan Keselamatan Penerbangan Sipil (CASR)sebagaimana telah diubah terakhir dengan Peraturan MenteriPerhubungan Nomor KM 57 Tahun 2010;

6 Keputusan Menteri Perhubungan Nomor KM 18 Tahun 2002 tentangPersyaratan-Persyaratan Sertifikasi dan Operasi bagi PerusahaanAngkutan Udara Niaga untuk Penerbangan Komuter dan Chartersebagaimana diubah terakhir dengan Peraturan Menteri PerhubunganNomor KM 42 Tahun 2009;

7 Peraturan Menteri Perhubungan Nomor KM 22 Tahun 2002 tentangPersyaratan-Persyaratan Sertifikasi dan Operasi bagi PerusahaanAngkutan Udara yang melakukan Penerbangan Dalam Negeri,Internasional dan Angkutan Udara Niaga Tidak Berjadwal sebagaimanadiubah terakhir dengan Peraturan Menteri Perhubungan Nomor KM 43Tahun 2009;

8 Peraturan Menteri Perhubungan Nomor KM 60 Tahun 2010 tentangOrganisasi dan Tata Kerja Kementerian Perhubungan;

MEMUTUSKAN:

Menetapkan : PERATURAN DIREKTUR JENDERAL PERHUBUNGAN UDARAMENGENAI PETUNJUK DAN TATA CARA BAGIAN 120-CSEA 001(ADVISORY CIRCULAR PART 120-CSEA 001) PANDUAN BAGIOPERATOR UNTUK PROGRAM PELATIHAN PENGGUNAANSISTEM PERINGATAN DAN SITUASI TERHADAP DARATAN(GUIDANCE FOR OPERATORS ON TRAINING PROGRAMMES FORTHE USE OF TERRAIN AWARENESS AND WARNING SYSTEM).

Pasal 1

Petunjuk dan Tata Cara Bagian 120-CSEA 001 (Advisory Circular Part120-CSEA 001) Panduan Bagi Operator untuk Program PelatihanPenggunaan Sistem Peringatan dan Situasi Terhadap Daratan(Guidance for Operators on Training Programmes for The Use ofTerrain Awareness and Warning System) sebagaimana tercantumdalam lampiran Peraturan.

Pasal 2

Direktur Kelaikan Udara dan Pengoperasian Pesawat Udaramengawasi pelaksanaan Peraturan ini.

Pasal 3

Peraturan ini mulai berlaku pada tanggal ditetapkan.

Ditetapkan di : JakartaPada tanggal : 12 Januari 2012

DIREKTUR JENDERAL PERHUBUNGAN UDARA,

ttd

HERRY BAKTI

SALINAN Peraturan ini disampaikan kepada:

1. Sekretaris Jenderal;

2. Inspektur Jenderal;3. Sekretaris Direktorat Jenderal Perhubungan Udara;4. Para Direktur di lingkungan Ditjen Perhubungan Udara;5. Para Kepala Otoritas Bandar Udara;

6. Para Kepala Bandar Udara UPTdi lingkungan Ditjen Perhubungan Udara;7. Direktur Utama PT. Angkasa Pura I (Persero);8. Direktur Utama PT. Angkasa Pura II (Pesero).

Salinan sesuai dengan aslinya

KEPALA BAGIAN HUKUM DAN HUMAS

ISRAFULHAYAT

Pembina (IV/a)NIP. 19680619 199403 1 002

Lampiran Peraturan Direktur Jenderal Perhubungan Udara

Nomor : KP 012 tahun 2012

Tanggal : 12 Januari 2012

Advisory Circular

120-CSEA 001

GUIDANCE FOR OPERATORS ON TRAININGPROGRAMMES FOR THE USE OF TERRAIN

AWARENESS AND WARNING SYSTEM

Amendment : 0

Date

REPUBLIC OF INDONESIA - MINISTRY OF TRANSPORTATIONDIRECTORATE GENERAL OF CIVIL AVIATIONJAKARTA - INDONESIA

2. TAWS MANEUVER TRAINING

The pilot should demonstrate the knowledge required to respond correctly toTAWS cautions and warnings. This training should address the followingtopics:

Chapter II

1) Response to Cautions

Objective: To verify that the pilot properly interprets and respondsto cautions.

Criteria: The pilot should demonstrate that he understands theneed, without delay:

• To initiate action required to correct the conditionthat has caused TAWS to issue the caution and tobe prepared to respond to a warning if this shouldfollow.

• If a warning does not follow the caution, to notifythe controller of the new position, heading and/oraltitude/flight level of the aircraft, and what thecommander intends to do next.

• The proper response to a caution might require thepilot:

- to reduce a rate of descent and/or to initiate aclimb;

- to regain an ILS glide path from below, or toinhibit a glide path signal if an ILS is not beingflown;

- to select more flap, or t o inhibit a flap sensor ifthe landing is being conducted with the intentthat the normal flap setting will not be used;

- to select gear down;- to initiate a turn away from the terrain or

obstacle ahead and towards an area free ofsuch obstructions if a forward looking terraindisplay indicates this to be a good solution andthe entire maneuver can be carried out in clearvisual conditions.

2) Response to Warnings

Objective: To verify that the pilot properly interprets and respondsto warnings.

Criteria: The pilot should demonstrate that he understands the

need, without delay:

• To initiate a climb in the manner specified by theoperator, and

• to maintain the climb until visual verification can be

made that the aircraft will clear the terrain orobstacle ahead, or until above the appropriatesector safe altitude (if certain as to the location ofthe aircraft with respect t o terrain) even if theTAWS warning stops. If, subsequently, the aircraftclimbs up through the sector safe altitude but thevisibility does not allow the crew to confirm that theterrain hazard has ended, checks should be madeto verify the location of the aircraft and to confirmthat the altimeter subscale settings are correct,

• Also, and when the workload permits, the crewshould notify the controller of the new position andaltitude/flight level, and what the commanderintends to do next.

• The manner in which the climb should be made willreflect the type of aircraft and the method specifiedby the aircraft manufacturer (but reflected in theoperations manual) for performing the escapemaneuver. Essential aspects will include the needfor an increase in pitch attitude, selection ofmaximum thrust, confirmation that external sourcesof drag (e.g. spoilers/speedbrakes) are retracted,and respect of the stick shaker or other indicationof eroded stall margin.

• TAWS warnings must never be ignored. However,the pilot's response may be limited to thatappropriate for a caution only if the aeroplane isbeing operated by day in clear visual conditions,and it is immediately obvious to the pilot that theaircraft is in no danger in respect of itsconfiguration, proximity to terrain or current flightpath.

Chapter II U_8

TAWS INITIAL EVALUATION

a. Pilot understanding of the academic training items should be assessedby means of a written test.

b. Pilot understanding of the maneuver training items should be assessedin a flight simulator (if available) equipped with TAWS visual and auraldisplays and inhibit selectors similar in appearance and operation tothose in the aircraft the pilot will fly, and the results assessed by asynthetic flight instructor, synthetic flight examiner, type rating instructoror type rating examiner.

c. The range of scenarios should be designed to give confidence thatproper and timely responses to TAWS cautions and warnings will resultin the aircraft avoiding a CFIT accident. To achieve this objective, thepilot should demonstrate taking the correct action to prevent a cautiondeveloping into a warning and, separately, the escape maneuverneeded in response to a warning. These demonstrations should takeplace when the external visibility is zero, though there is much to belearnt if, initially, the training is given in 'mountainous' or 'hilly' terrain withclear visibility. This training should comprise a sequence of scenarios,rather than be included in line orientated flying training (LOFT).

d. A record should be made, after the pilot has demonstrated competence,of the scenarios that were practiced.

4. TAWS RECURRENT TRAINING (ANNUAL)

a. TAWS recurrent training ensures that pilots maintain the appropriateTAWS knowledge and skills. In particular, it reminds pilots of the need toact promptly in response to cautions and warnings, and of the unusualattitude associated with flying the escape maneuver.

b. An essential item of recurrent training is the discussion ofany significantissues and operational concerns that have been identified by theoperator. Recurrent training should also address changes to TAWSlogic, parameters or procedures and to any unique TAWScharacteristics of which pilots should be aware.

Chapter II ^r

CHAPTER 3

REPORTING PROCEDURES

1. VERBAL REPORTS

Verbal reports should be made promptly to the appropriate air trafficcontrol unit:

• Whenever any maneuver has caused the aircraft to deviate from anair traffic clearance;

• When, subsequent to a maneuver that has caused the aircraft t odeviate from an air traffic clearance, the aircraft has returned to aflight path that complies with the clearance;

• When air traffic issue instructions that, if followed, would cause thecrew to maneuver the aircraft towards terrain or obstacle that, itwould appear from the display that a potential CFIT occurrence islikely to result.

2. WRITTEN REPORTS

Written reports should be submitted in accordance with the operator'soccurrence reporting scheme:

• Whenever the aircraft flight path has been modified in response to aTAWS alert (false, nuisance or genuine).

Written reports should be made in the aircraft technical log:

• Whenever a TAWS alert has been issued and is believed to havebeen false; or,

• if it is believed that a TAWS alert should have been issued but wasnot.

Within this AC, and with regard to reports:

• The term 'false' means that TAWS issued an alert that could notpossibly be justified by the position of the aircraft in respect to terrain,and it is probable that a fault or failure in the system (equipmentand/or input data) has been the cause.

•

Chapter

The term 'nuisance' means that TAWS issued an alert that wasappropriate but not needed because the flight crew could determineby independent means that the flight path was at that time safe;

The term 'genuine' means that TAWS issued an alert that was bothappropriate and ' necessary.

These terms have value in assessing, only after the occurrence isover and to facilitate subsequent analysis, the adequacy of theequipment and the programs it contains. It is not intended that flightcrew should attempt t o classify an alert into any of these threecategories when visual and/or aural cautions or warnings areannunciated.

Chapter III " [[j^~