Removal of the Pylon Fire-Detector Harness

TASK 26-12-63-000-801-A
Removal of the Pylon Fire-Detector Harness

WARNING: BE CAREFUL WHEN YOU DO WORK ON THE ENGINE AFTER SHUTDOWN. THE ENGINE 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: 415
ZONE: 425
ZONE: 473
ZONE: 483
FIN: 31WD1 ** ON A/C NOT FOR ALL
FIN: 31WD2 ** ON A/C NOT FOR ALL
FIN: 32WD1 ** ON A/C NOT FOR ALL
FIN: 32WD2 ** ON A/C NOT FOR ALL
FIN: 41WD1 ** ON A/C NOT FOR ALL
FIN: 41WD2 ** ON A/C NOT FOR ALL
FIN: 42WD1 ** ON A/C NOT FOR ALL
FIN: 42WD2 ** 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 2M (6 FT) - ADJUSTABLE
No specific	AR	SAFETY CLIP - CIRCUIT BREAKER

B. Work Zones and Access Panels

ZONE/ACCESS	ZONE DESCRIPTION
415	LOWER PYLON
425	LOWER PYLON
473	LOWER FAIRING
483	LOWER FAIRING
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 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
Pylon Fire Detector Harness

3. Job Set-up
Subtask 26-12-63-861-050-A ** ON A/C NOT FOR ALL

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

Subtask 26-12-63-941-050-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 26-12-63-865-050-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 26-12-63-010-050-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 26-12-63-040-050-A ** ON A/C NOT FOR ALL

E. Deactivation of the Thrust Reverser for 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 maintenance (Ref. AMM TASK 78-30-00-040-805).

Subtask 26-12-63-010-051-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 2M (6 FT) - ADJUSTABLE in position.

4. Procedure
Subtask 26-12-63-020-050-B ** ON A/C NOT FOR ALL

A. Removal of the Pylon Fire-Detector Harness

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) FOR [31WD1] (HARNESS-FIRE DET, ENG 1 PYLON LOOP A STUD A), [31WD2] (HARNESS-FIRE DET, ENG 2 PYLON LOOP A STUD A), [41WD1] (HARNESS-FIRE DET, ENG 1 PYLON LOOP B STUD A), [41WD2] (HARNESS-FIRE DET, ENG 2 PYLON LOOP B STUD A)
(a) Disconnection of the related sensing element (4) from the responder unit (1)
1 Turn the related quarter-turn fastener (5) by one quarter of a turn and open the clamp (7).
2 Disengage the sensing element (4) from the clamp (7).
3 Remove the nut (3) from the responder unit (1).
4 Disconnect the sensing element (4) from the responder unit (1).
(b) Turn the related quarter-turn fasteners (9) by one quarter of a turn and open the clamps (10).
1 Disengage the sensing element (4) from the clamps (10).
(c) Removal of the welded assembly (20)
1 Remove the two bolts (12) and washers (13).
2 Remove the closure plate (17) from the welded assembly (20).
3 Remove the four bolts (18) and (19) to disconnect the four electrical cables (22) from the four sensing elements (4).
4 Remove the three bolts (16) and washers (15).
5 Disconnect the welded assembly (20) from the junction box (14).
(d) Removal of the related sensing element (4) from the welded assembly (20)
1 Remove the nut (21) from the sensing element (4).
2 Turn the quarter-turn fastener (6) by one quarter of a turn and open the clamp (8).
3 Disengage the sensing element (4) from the clamp (8).
4 Remove the sensing element (4) from the welded assembly (20).
(e) Carefully remove the sensing element (4) from the rail assembly (11).
(2) FOR [32WD1] (HARNESS-FIRE DET, ENG 1 PYLON LOOP A STUD C), [32WD2] (HARNESS-FIRE DET, ENG 2 PYLON LOOP A STUD C), [42WD1] (HARNESS-FIRE DET, ENG 1 PYLON LOOP B STUD C), [42WD2] (HARNESS-FIRE DET, ENG 2 PYLON LOOP B STUD C)
(a) Disconnection of the related sensing element (4) from the responder unit (1)
1 Turn the related quarter-turn fastener (5) by one quarter of a turn and open the clamp (7).
2 Disengage the sensing element (4) from the clamp (7).
3 Remove the nut (2) from the responder unit (1).
4 Disconnect the sensing element (4) from the responder unit (1).
(b) Turn the related quarter-turn fasteners (9) by one quarter of a turn and open the clamps (10).
1 Disengage the sensing element (4) from the clamps (10).
(c) Removal of the welded assembly (20)
1 Remove the two bolts (12) and washers (13).
2 Remove the closure plate (17) from the welded assembly (20).
3 Remove the four bolts (18) and (19) to disconnect the four electrical cables (22) from the four sensing elements (4).
4 Remove the three bolts (16) and washers (15).
5 Disconnect the welded assembly (20) from the junction box (14).
(d) Removal of the related sensing element (4) from the welded assembly (20)
1 Remove the nut (21) from the sensing element (4).
2 Turn the quarter-turn fastener (6) by one quarter of a turn and open the clamp (8).
3 Disengage the sensing element (4) from the clamp (8).
4 Remove the sensing element (4) from the welded assembly (20).
(e) Carefully remove the sensing element (4) from the rail assembly (11).

[Rev.10 from 2021] 2026.03.31 23:43:30 UTC