Removal of the Core Fire Detectors from the Rail Assembly

TASK 26-12-17-000-001-A
Removal of the Core Fire Detectors from the Rail Assembly

CAUTION: USE CARE WHEN YOU REMOVE THE FIRE DETECTOR SENSORS FROM THE RAIL ASSEMBLY. THE FIRE DETECTOR SENSOR TUBE CAN CRACK AND CAUSE SERIOUS DAMAGE TO THE UNIT.

NOTE: This procedure can be done with the rail assembly installed on the engine, or with the rail assembly removed from the engine.

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	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-A	Opening of the Fan Cowl Doors
TASK 78-30-00-481-041-A	Make the Thrust Reverser Unserviceable for Maintenance
TASK 78-36-00-010-040-A	Opening of the Thrust Reverser Doors
Core Fire Detector (4001WD1, 4001WF2)

3. Job Set-up
Subtask 26-12-17-861-058-A ** ON A/C NOT FOR ALL

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

Subtask 26-12-17-941-058-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) in position to tell persons not to start the engine.
(2) Make sure that the engine 1(2) shutdown occurred not less than 5 minutes before you do this procedure.
(3) On the ENG section of the maintenance panel 50VU:
(a) Make sure that the ON legend of the FADEC GND PWR/1(2) pushbutton switch is off.
(b) Put a WARNING NOTICE(S) in position to tell persons not to energize the FADEC 1(2).

Subtask 26-12-17-865-066-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 26-12-17-010-073-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 26-12-17-040-062-A ** ON A/C NOT FOR ALL

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

Subtask 26-12-17-010-074-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 26-12-17-020-059-A ** ON A/C NOT FOR ALL

A. Removal of the Core Fire Detector Sensors from the Rail Assembly

Core Fire Detector (4001WD1, 4001WF2) ** ON A/C NOT FOR ALL

CAUTION: MAKE SURE NOT TO BEND OR KINK THE FIRE DETECTOR ELEMENTS (75). DAMAGE TO THE ELEMENTS CAN MAKE THE FIRE DETECTION SYSTEM NOT WORK.

(1) Remove the core fire detector sensors (75) from the rail assembly (50).

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! BEFORE SPIB NO. CFM99300MW1 !

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(a) Open the clamps (70) on the core fire detector elements (75).
(b) Remove the fire detector elements (75) from the clamps (70).

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! AFTER SPIB NO. CFM99300MW1 !

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(c) Remove the bolts (80) and clamp covers (85) that attach the fire detector elements (75) to the rail assembly (50).
(d) Remove the fire detector sensors (75) from the inserts (90), (95).

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! END SPIB NO. CFM99300MW1 !

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(2) Remove the wire harness from the LH core loop A fire detector sensor (4001WD1).
(a) Remove the nut (15) from terminal A of the sensor. Remove wire (45) from terminal A.
(b) Remove the nut (20) from terminal B of the sensor. Remove wire (25) from terminal B.

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

(c) Cut the lockwire and remove the screws (5) that attach the harness clamp (10) to the fire detector sensor (40).
(d) Remove the loop A wire harness from the fire detector sensor (40).
(e) Put the harness clamp (10) on the fire detector sensor (40) and attach it with the screws (5).
(3) Remove the LH core loop A fire detector sensor 4001WD1 (40) from the rail assembly (50) and from the engine bracket.
(a) Remove the bolts (30) and washers (35) that attach the fire detector sensor (40) and rail assembly (50) to the engine bracket.
(b) Remove the fire detector sensor (40) from the rail assembly (50) and from the engine bracket.
(4) Remove the wire harness from the RH core loop B fire detector sensor (4001WD2).
(a) Remove the nut (15) from terminal A of the sensor. Remove wire (45) from terminal A.
(b) Remove the nut (20) from terminal B of the sensor. Remove wire (25) from terminal B.

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

(c) Cut the lockwire and remove the screws (5) that attach the harness clamp (10) to the fire detector sensor (40).
(d) Remove the loop B wire harness from the fire detector sensor (40).
(e) Put the harness clamp (10) on the fire detector sensor (40) and attach it with the screws (5).
(5) Remove the RH core loop A fire detector sensor 4001WD2 (40) from the rail assembly (50) and from the engine bracket.
(a) Remove the bolts (30) and washers (35) that attach the fire detector sensor (40) and rail assembly (50) to the engine bracket.
(b) Remove the fire detector sensor (40) from the rail assembly (50) and from the engine bracket.

CAUTION: DO NOT DISASSEMBLE THE FIRE DETECTOR SENSORS. THE DETECTOR SENSOR IS A HERMETICALLY SEALED UNIT AND IS NOT REPAIRABLE. IF YOU TRY TO DISASSEMBLE THE DETECTOR SENSORS, YOU WILL CAUSE SERIOUS DAMAGE TO THE UNIT.

(6) Remove the fire detector sensors.

[Rev.10 from 2021] 2026.03.31 23:43:00 UTC