Removal of the N1 Speed Sensor [CFMB]

TASK 77-11-10-000-002-A
Removal of the N1 Speed Sensor

FIN: 4000EV ** 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	AR	CAP - BLANKING
No specific	AR	CONTAINER 1 L (1/4 USGAL)
No specific	AR	PLIERS - CONNECTOR, JAW, SOFT
No specific	AR	SHEATH - PROTECTIVE
No specific	AR	WARNING NOTICE(S)

B. Work Zones and Access Panels

ZONE/ACCESS	ZONE DESCRIPTION
FOR [1000EM1] (ENGINE-1)
437AL, 438AR
FOR [1000EM2] (ENGINE-2)
447AL, 448AR

C. Referenced Information

REFERENCE	DESIGNATION
TASK 71-13-00-010-040-B	Opening of the Fan Cowl Doors
N1 Speed Sensor

3. Job Set-up
Subtask 77-11-10-941-051-A ** ON A/C NOT FOR ALL

A. Safety Precautions
(1) On the center pedestal, on the ENG panel 115VU:
(a) Put a WARNING NOTICE(S) 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 overhead maintenance panel 50VU:
(a) Make sure that the ON legend of the ENG/FADEC GND PWR/1(2) pushbutton switch is off.
(b) Put a WARNING NOTICE(S) to tell persons not to energize the FADEC 1(2).

Subtask 77-11-10-010-051-A ** ON A/C NOT FOR ALL

B. 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

4. Procedure
Subtask 77-11-10-020-051-A ** ON A/C NOT FOR ALL

A. Removal of the N1 Speed Sensor
(1) Disconnect the electrical cables from the N1 speed sensor (40). Use PLIERS - CONNECTOR, JAW, SOFT only if necessary.
(2) Put the CAP-BLANKING on each disconnected electrical connector and receptacle.

CAUTION: DO NOT REMOVE THE GUIDE TUBE LOCKING BOLT. DAMAGE OF THE GUIDE TUBE O-RINGS CAN OCCUR, WHICH CAN CAUSE OIL LEAKAGE.

(3) Remove the 2 bolts (60) which attach the N1 speed sensor to the fan frame (20).
(4) Put a CONTAINER 1 L (1/4 USGAL) under the N1 speed sensor.

NOTE: A 3 in.3 (50 cm3) to 6 in.3 (100 cm3) oil leakage can occur when you remove the N1 speed sensor.

(5) Slowly and carefully pull the sensor out of the probe guide (10) and remove the N1 speed sensor (40) from the fan frame.
(6) Remove the O-ring (50) from the probe guide (10). Discard the O-ring (50).
(7) Put a SHEATH - PROTECTIVE on the probe part of the N1 speed sensor.
(8) Remove the container.

[Rev.10 from 2021] 2026.04.01 12:59:49 UTC