Removal of the Aft Fire/Overheat Detector

TASK 26-12-17-000-803-A
Removal of the Aft Fire/Overheat Detector

WARNING: BE CAREFUL WHEN YOU DO WORK ON THE ENGINE AND THE ADJACENT COMPONENTS AFTER ENGINE SHUTDOWN. THE ENGINE, THE ENGINE OIL AND THE ADJACENT COMPONENTS CAN STAY HOT FOR A LONG TIME. IF YOU DO NOT OBEY THIS INSTRUCTION, INJURY CAN OCCUR.

WARNING: WEAR APPLICABLE PERSONAL PROTECTIVE EQUIPMENT (PPE) WHEN YOU DO THIS TASK. BEFORE YOU USE PPE, READ, UNDERSTAND AND OBEY ALL INSTRUCTIONS FOR ITS USE. THESE INSTRUCTIONS INCLUDE INSTRUCTIONS FROM THE MANUFACTURER, YOUR EMPLOYER AND GOVERNMENT REGULATIONS. YOU CAN GET INJURED IF YOU DO NOT USE PPE. GET INSTRUCTIONS FROM YOUR EMPLOYER ON WHICH PPE IS NECESSARY.

ZONE: 450
ZONE: 460
FIN: 4001WD1 ** ON A/C NOT FOR ALL
FIN: 4001WD2 ** ON A/C NOT FOR ALL

1. Reason for the Job
Self explanatory
2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment

REFERENCE	QTY	DESIGNATION
No specific	1	ACCESS PLATFORM 1M(3 FT)
No specific	AR	COVER - PROTECTION
No specific	AR	SAFETY CLIP - CIRCUIT BREAKER

B. Work Zones and Access Panels

ZONE/ACCESS	ZONE DESCRIPTION
450	ENG 1 THRUST REVERSER & EXHAUST SECTION
460	ENG 2 THRUST REVERSER & EXHAUST SECTION
FOR [4020KM1] (POWER PLANT-DEMOUNTABLE, ENG 1)
437AL, 438AR, 451AL, 452AR
FOR [4020KM2] (POWER PLANT-DEMOUNTABLE, ENG 2)
447AL, 448AR, 461AL, 462AR

C. Referenced Information

REFERENCE	DESIGNATION
TASK 24-42-00-861-001-A	Energize the Ground Service Network from the External Power
TASK 26-12-61-000-802-A	Removal of the Loop-A Fire Electrical Harness and the Loop-A Fire Detector Cables
TASK 26-12-62-000-802-A	Removal of the Loop-B Fire Harness
TASK 71-00-00-860-833-A	Procedure to Prevent Engine Motoring
TASK 71-13-00-010-802-A	Opening of the Fan Cowl Doors
TASK 78-30-00-040-805-A	Deactivation of the Thrust Reverser System for Ground Maintenance
TASK 78-36-00-010-802-A	Opening of the Thrust Reverser Cowl-Doors
Aft Fire/Overheat Detector

3. Job Set-up
Subtask 26-12-17-861-062-A ** ON A/C NOT FOR ALL

A. Energize the ground service network (Ref. AMM TASK 24-42-00-861-001).

Subtask 26-12-17-941-062-A ** ON A/C NOT FOR ALL

B. Safety Precautions
(1) Do the procedure to prevent engine motoring
(Ref. AMM TASK 71-00-00-860-833).

Subtask 26-12-17-865-074-A ** ON A/C NOT FOR ALL

C. Open, safety and tag this(these) circuit breaker(s):

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C NOT FOR ALL
FOR FIN: 4020KM1 (POWER PLANTDEMOUNTABLE, ENG 1)
49VU	ENGINE/1/FIRE DET/LOOP A	7WD1	A06
121VU	ENGINE/ENG1/FIRE DET/LOOP B	8WD1	Q38
FOR FIN: 4020KM2 (POWER PLANTDEMOUNTABLE, ENG 2)
49VU	ENGINE/2/FIRE DET/LOOP B	8WD2	A07
121VU	ENGINE/ENG2/FIRE DET/LOOP A	7WD2	Q39

Subtask 26-12-17-010-084-A ** ON A/C NOT FOR ALL

D. Get Access
(1) Open the fan cowl doors (Ref. AMM TASK 71-13-00-010-802):
(a) FOR [4020KM1] (POWER PLANT-DEMOUNTABLE, ENG 1)
437AL 438AR
(b) FOR [4020KM2] (POWER PLANT-DEMOUNTABLE, ENG 2)
447AL 448AR

Subtask 26-12-17-040-067-A ** ON A/C NOT FOR ALL

E. Deactivation of the Thrust Reverser for Ground Maintenance

WARNING: YOU MUST DEACTIVATE THE THRUST REVERSER BEFORE YOU DO WORK ON OR AROUND IT. IF YOU DO NOT, THE THRUST REVERSER CAN OPERATE ACCIDENTALLY AND CAUSE AN INJURY AND/OR DAMAGE.

(1) Do the deactivation of the thrust reverser system for ground maintenance (Ref. AMM TASK 78-30-00-040-805).

Subtask 26-12-17-010-085-A ** ON A/C NOT FOR ALL

F. Get Access
(1) Open the thrust reverser cowl-doors (Ref. AMM TASK 78-36-00-010-802):
(a) FOR [4020KM1] (POWER PLANT-DEMOUNTABLE, ENG 1)
451AL 452AR
(b) FOR [4020KM2] (POWER PLANT-DEMOUNTABLE, ENG 2)
461AL 462AR
(2) Put an ACCESS PLATFORM 1M(3 FT) in position, if necessary.

4. Procedure
Subtask 26-12-17-020-064-A ** ON A/C NOT FOR ALL

A. Removal of the Aft Fire/Overheat Detector

CAUTION: WIPE CLEAN ALL PARTS AND TOOLS AS NECESSARY TO REMOVE UNWANTED DEBRIS AND PREVENT DAMAGE TO THE ENGINE.

CAUTION: DO NOT USE ELECTRICAL OR PNEUMATIC TOOLS TO LOOSEN OR TIGHTEN THE QUARTER-TURN FASTENER ON THE FIRE DETECTOR CLAMP. ONLY USE A MANUAL SCREWDRIVER. ELECTRICAL OR PNEUMATIC TOOLS WILL CAUSE THE FASTENER TO TURN TOO MUCH AND POSSIBLY TO BREAK.

(1) Disconnect the loop-B fire harness from the fire detector element (1) (Ref. AMM TASK 26-12-62-000-802).
(2) Disconnect the loop-A electrical rail assembly from the fire detector element (10) (Ref. AMM TASK 26-12-61-000-802).
(3) Remove the aft fire detector elements (1) and (10) as follows:
(a) Remove the screw (2), the two screws (5), the washer (3) and the two washers (4) that attach the aft fire detector element (1) to the mounting bracket.
(b) Remove the four screws (7) and (8) and four washers (6) and (9) that attach the aft fire detector element (10) to the mounting bracket.
(c) Turn the 28 screws of the two single-hinged clamps (11) and the 26 double-hinged clamps (12) counterclockwise. Open the 28 clamps (11) and (12).
(d) Remove the aft fire detector elements (1) and (10) from the fire detection support rails and engine.
(4) Installation of the protection covers

CAUTION: INSTALL PROTECTION COVERS ON ALL THE OPENINGS IMMEDIATELY TO PREVENT DAMAGE TO THE ENGINE.

(a) Make sure that you install all the necessary COVER - PROTECTION to prevent damage to the engine.

[Rev.10 from 2021] 2026.03.31 23:43:12 UTC