Installation of the N1 Speed Sensor [CFMB]

TASK 77-11-10-400-002-A
Installation 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	PLIERS - CONNECTOR, JAW, SOFT
No specific	AR	TAPE - ADHESIVE
No specific	AR	WARNING NOTICE(S)
No specific	Torque wrench: range to between 120 and 110 lbf.in (1.36 and 1.24 m.daN )

B. Consumable Materials

REFERENCE	DESIGNATION
(Material No.CP2101)	graphite grease
(Material No.CP2179)	lanolin
(Material No.CP2442)	engine oil
(Material No.CP5070)	vaseline
(Material No.14SBA1)	Textile-Lint free Cotton -

C. Work Zones and Access Panels

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

D. Expendable Parts

FIG.ITEM	DESIGNATION	IPC-CSN
50	O-RING	AIPC 77-11-10-01-050

E. Referenced Information

REFERENCE	DESIGNATION
TASK 71-13-00-010-040-B	Opening of the Fan Cowl Doors
TASK 71-13-00-410-040-B	Closing of the Fan Cowl Doors
TASK 73-29-00-710-040-B	Operational Test of the FADEC on the Ground (with Engine Motoring)
TASK 73-29-00-710-040-B-02	Operational Test of the FADEC on the Ground (with Engine Non motoring)
N1 Speed Sensor

3. Job Set-up
Subtask 77-11-10-860-051-A ** ON A/C NOT FOR ALL

A. Aircraft Maintenance Configuration
(1) On the center pedestal, on the ENG panel 115VU, make sure that a WARNING NOTICE(S) is in position to tell persons not to start the engine.
(2) On the overhead maintenance panel 50VU, make sure that the ON legend of the ENG/FADEC GND PWR/1(2) pushbutton switch is off. Make sure that a WARNING NOTICE(S) is in position to tell persons not to energize the FADEC 1(2).

Subtask 77-11-10-010-053-A ** ON A/C NOT FOR ALL

B. Make sure that the fan cowl doors are open (Ref. AMM TASK 71-13-00-010-040):
(1) FOR [1000EM1] (ENGINE-1)
437AL 438AR
(2) FOR [1000EM2] (ENGINE-2)
447AL 448AR

4. Procedure
Subtask 77-11-10-420-051-A ** ON A/C NOT FOR ALL

A. Installation of the N1 Speed Sensor
(1) Lubricate a new O-ring (50) with engine oil (Material No.CP2442) .
(2) Install the new AIPC 77-11-10-01-050 O-RING (50) in the recess of the probe guide (10).
(3) Remove the protective sheath from the sensor probe.
(4) Clean the pole pieces of the sensor probe with a Textile-Lint free Cotton - (Material No.14SBA1) .
(5) Complete the cleaning with a piece of TAPE - ADHESIVE to remove any magnetic particles.
(6) Lubricate the two probe dampers with vaseline (Material No.CP5070) or lanolin (Material No.CP2179) .
(7) Install the N1 speed sensor (40) as follows:

CAUTION: DO NOT USE TOO MUCH FORCE WHEN YOU ENGAGE THE SENSOR PROBE IN THE FAN FRAME PROBE GUIDE TO PREVENT DAMAGE TO THE PROBE.

(a) Align the sensor probe with the probe guide (10). Engage the probe in the probe guide and push it slowly down the guide. Be careful to keep axial alignement and a smooth movement throughout the probe engagement.
(b) When the sensor probe is fully engaged by hand and in the free state (bolts (60) not installed), measure the gap between the machined surfaces of:
1 the mounting flange of the N1 speed sensor,
2 the sleeve (70)
(c) The measured gap must be between 0.12 in. (3.08 mm) and 0.24 in. (6.09 mm) .
(d) If the gap is not in the limits before installation of bolts (60),

CAUTION: THE N1 SPEED SENSOR IS SPRING-LOADED TO KEEP ITS INNER END SHOULDER IN CONTACT WITH THE BOTTOM OF THE PROBE RECESS. FAILURE TO OBEY TO THE GAP LIMITS SPECIFIED ABOVE CAN RESULT IN DAMAGE TO THE SENSOR.

1 Remove the sensor and find the cause (distortion of the probe, mis-positioning, etc.).
(e) If you cannot get the correct gap, remove the N1 speed sensor and replace it by a serviceable sensor.
(f) TORQUE the bolts as follows:

CAUTION: WHEN YOU TORQUE THE BOLTS, USE TIGHTENING INCREMENTS TO PREVENT DISTORTION OF THE SENSING PROBE. GET NEAR THE FINAL TORQUE BY SMALL QUANTITIES: ONE BOLT THEN THE OTHER, AND REPEAT. TO MAKE SURE THAT YOU APPLY THE SAME TORQUE ON THE 2 BOLTS AT THE SAME TIME, THE USE OF 2 RATCHET WRENCHES IS STRONGLY RECOMMENDED.

1 Lubricate the threads of the two bolts (60) with graphite grease (Material No.CP2101) . Attach the N1 speed sensor (40) to the fan frame, with the two bolts (60).
(g) TORQUE the bolts (60) to between 120 and 110 lbf.in (1.36 and 1.24 m.daN )

.
(8) Install the connector:

CAUTION: CAREFULLY ALIGN THE CONNECTOR KEY WITH THE RECEPTACLE KEYWAY BEFORE YOU CONNECT THEM TO PREVENT DAMAGE TO THE CONNECTORS.

(a) Remove the CAP-BLANKING from each electrical connector and receptacle.
(b) Make sure that the connectors and the receptacles are clear of unwanted materials.
(c) Connect the cable connectors to the N1 speed sensor receptacles. Use PLIERS - CONNECTOR, JAW, SOFT only if necessary.
(d) Make sure the connectors are fully engaged and do not move.
(9) Do a FADEC ground test (engine motoring) (Ref. AMM TASK 73-29-00-710-040).

5. Close-up
Subtask 77-11-10-410-051-A ** ON A/C NOT FOR ALL

A. Close Access
(1) Make sure that the work area is clean and clear of tools and other items.
(2) Close the fan cowl doors (Ref. AMM TASK 71-13-00-410-040):
(a) FOR [1000EM1] (ENGINE-1)
437AL 438AR
(b) FOR [1000EM2] (ENGINE-2)
447AL 448AR
(3) Remove the WARNING NOTICE(S).

[Rev.10 from 2021] 2026.04.01 03:17:18 UTC