Removal of the Core Fire Detectors

TASK 26-12-17-000-041-A
Removal of the Core Fire Detectors

WARNING: BE CAREFUL WHEN YOU DO WORK ON THE ENGINE PARTS AFTER THE ENGINE SHUTDOWN. USE APPLICABLE THERMAL GLOVES. THE ENGINE PARTS CAN STAY HOT FOR ONE HOUR AFTER SHUTDOWN AND CAN BURN YOU.

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	SAFETY CLIP - CIRCUIT BREAKER
No specific	AR	SCREWDRIVER - PHILLIPS HEAD
No specific	AR	WARNING NOTICE(S)

B. Work Zones and Access Panels

ZONE/ACCESS	ZONE DESCRIPTION
FOR [1000EM1] (ENGINE-1)
437AL, 438AR, 451AL, 452AR
FOR [1000EM2] (ENGINE-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 71-13-00-010-040-B	Opening of the Fan Cowl Doors
TASK 78-30-00-481-041-B	Make the Thrust Reverser Unserviceable for Maintenance
TASK 78-36-00-010-040-B	Opening of the Thrust Reverser Doors
Core Fire Detector - Left Side
Core Fire Detector - Right Side

3. Job Set-up
Subtask 26-12-17-861-050-A ** ON A/C NOT FOR ALL

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

Subtask 26-12-17-941-050-A ** ON A/C NOT FOR ALL

B. Safety Precautions
(1) On the center pedestal, on the ENG panel 115VU:
(a) Make sure that the ENG/MODE/CRANK/NORM/IGN/START selector switch is in the NORM position.
(b) Put a WARNING NOTICE(S) to tell persons not to start the engine 1(2).
(2) Make sure that the engine 1(2) has been shutdown for at least 5 minutes.
(3) On the overhead maintenance panel 50VU:
(a) Make sure that the ON legend of the ENG/FADEC GND PWR/1(2) pushbutton switch is off.
(b) Install a WARNING NOTICE(S) to tell persons not to energize the FADEC 1(2).

Subtask 26-12-17-865-050-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
49VU	ENGINE/2/FIRE DET/LOOP B	8WD2	A07
49VU	ENGINE/1/FIRE DET/LOOP A	7WD1	A06
121VU	ENGINE/ENG2/FIRE DET/LOOP A	7WD2	Q39
121VU	ENGINE/ENG1/FIRE DET/LOOP B	8WD1	Q38

Subtask 26-12-17-010-050-A ** ON A/C NOT FOR ALL

D. Get Access
(1) Open the fan cowl doors (Ref. AMM TASK 71-13-00-010-040):
(a) FOR [1000EM1] (ENGINE-1)
437AL 438AR
(b) FOR [1000EM2] (ENGINE-2)
447AL 448AR
(2) Put the ACCESS PLATFORM 1M(3 FT) in position.

Subtask 26-12-17-040-050-A ** ON A/C NOT FOR ALL

E. Make the thrust reverser unserviceable (Ref. AMM TASK 78-30-00-481-041).

Subtask 26-12-17-010-051-A ** ON A/C NOT FOR ALL

F. Open the thrust reverser doors (Ref. AMM TASK 78-36-00-010-040):
(1) FOR [1000EM1] (ENGINE-1)
451AL 452AR
(2) FOR [1000EM2] (ENGINE-2)
461AL 462AR

4. Procedure
Subtask 26-12-17-020-050-A ** ON A/C NOT FOR ALL

A. Removal of the Core Fire Detectors

CAUTION: REMOVE THE FIRE DETECTORS AND THE RAIL AS ONE ASSEMBLY. THE FIRE DETECTOR SENSOR ELEMENTS CAN BE DAMAGED IF NOT SUPPORTED BY THE RAIL.

(1) Disconnect the rail assembly from the engine brackets, as follows:
(a) Turn the screw (10) on the center mount clamp (15), then move the clamps (15) out of the brackets (30) (10 locations). Use a SCREWDRIVER - PHILLIPS HEAD.
(2) Remove the wire harness (FIN 4204KS) from the Loop A fire-detector sensor (4001WD1):

Core Fire Detector - Left Side ** ON A/C NOT FOR ALL

(a) Remove the nut (50) from terminal C of the fire detector sensor (5). Remove the wire (55) from the terminal.
(b) Remove the nut (45) from terminal A of the fire detector sensor (5). Remove the wire (60) from the terminal.

NOTE: After the harness wires are removed, install the nuts on the fire detector terminals.

(c) Remove the nut (45), flat washers (70), lockwasher (85) from the ground stud (65). Remove the ground wire (80) from the ground stud.
(d) Cut the safety wire and remove the screws (35) that attach the harness clamp (40) to the fire detector sensor (5).
(e) Remove the loop A harness (4204KS) from the fire detector (30).
(f) Put the harness clamp (40) on the fire detector (30) and attach it with the screws (35).
(3) Remove the fire detector (5) and rail assembly (20) from the engine bracket:
(a) Remove the bolt (65), washer (70), and nut (75) that attach the fire detector to the engine bracket.
(b) Remove the rail assembly and fire detector from the engine bracket.
(4) Install the bolt (65), washer (70), and nut (75) on the engine bracket. Tighten the nut with your hand.
(5) Install the ground stud (65), flat washers (70), lockwasher (85), and nut (45) on the engine bracket. Tighten the nut with your hand.
(6) Remove the wire harness (4205KS) from the loop B fire detector (4001WD2):

Core Fire Detector - Right Side ** ON A/C NOT FOR ALL

(a) Remove the nut (50) from terminal C of the fire detector sensor (115). Remove the wire (110) from the terminal.
(b) Remove the nut (45) from terminal A of the fire detector sensor (115). Remove the wire (120) from the terminal.

NOTE: After the harness wires are removed, put the nuts on the fire detector terminals. Tighten the nuts with your hand.

(c) Remove the nut (45), flat washers (70), lockwasher (85) from the ground stud (65). Remove the ground wire (105) from the ground stud.
(d) Cut the safety wire and remove the screws (35) that attach the harness clamp (40) to the fire detector sensor (115).
(e) Remove the loop B harness (4205KS) from the fire detector (115).
(f) Put the harness clamp (40) on the fire detector (115) and attach it with the screws (35). Tighten the screws with your hand.
(7) Remove the fire detector (115) and rail assembly (20) from the engine bracket:
(a) Remove the bolts (65), washers (70), and nuts (75) that attach the fire detector to the engine bracket (2 locations).
(b) Remove the rail assembly and fire detector from the engine bracket.
(8) Install the bolts (65), washers (70), and nuts (75) on the engine bracket (2 locations). Tighten the nut with your hand.
(9) Install the ground stud (65), flat washers (70), lockwasher (85), and nut (45) on the engine bracket. Tighten the nut with your hand.
(10) Remove the rail assembly and fire detectors from the engine.

[Rev.10 from 2021] 2026.03.31 23:43:02 UTC