Removal of the N1 Sensor [CFML]

TASK 77-11-05-000-801-A
Removal of the N1 Sensor

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: 4064KS

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 - PROTECTION
No specific	1	CONTAINER 5 L (1.32 USGAL)
No specific	AR	COVER - PROTECTION
No specific	AR	WARNING NOTICE(S)

B. Work Zones and Access Panels

ZONE/ACCESS	ZONE DESCRIPTION
FOR [4020KM1] (POWER PLANT-DEMOUNTABLE, ENGINE 1)
437AL, 438AR, 452AR
FOR [4020KM2] (POWER PLANT-DEMOUNTABLE, ENGINE 2)
447AL, 448AR, 462AR

C. Referenced Information

REFERENCE	DESIGNATION
TASK 70-70-00-910-804-A	Electrical Standard Practices
TASK 71-13-00-010-803-A	Opening of the Fan Cowl Doors
TASK 72-24-01-000-801-A	Removal of Segment Shrouds 1 thru 5
TASK 78-30-00-040-809-A	Deactivation of the Thrust Reverser System for Ground Maintenance
TASK 78-36-00-010-806-A	Opening of the Thrust Reverser Cowl Doors
N1 Sensor

3. Job Set-up
Subtask 77-11-05-941-050-A

A. Safety Precautions
(1) On the center pedestal, on ENG panel 115VU:
(a) Make sure that the ENG/MODE selector switch is in the NORM position.
(b) Make sure that the ENG/MASTER 1(2) control switch was in the OFF position not less than five minutes before you do this procedure.
(c) Put WARNING NOTICE(S) in position to tell persons not to operate:

The ENG/MODE selector switch, and
The ENG/MASTER 1(2) control switch.

(2) On the ENG section of 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 FADEC 1(2).

Subtask 77-11-05-010-050-A

B. Get Access
(1) Open the fan cowl doors (Ref. AMM TASK 71-13-00-010-803):
(a) FOR [4020KM1] (POWER PLANT-DEMOUNTABLE, ENGINE 1)
437AL 438AR
(b) FOR [4020KM2] (POWER PLANT-DEMOUNTABLE, ENGINE 2)
447AL 448AR

Subtask 77-11-05-040-050-A

C. Deactivation of the Thrust Reverser System 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 78-30-00-040-809).

Subtask 77-11-05-010-051-A

D. Open the right thrust-reverser cowl-door (Ref. AMM TASK 78-36-00-010-806):
(1) FOR [4020KM1] (POWER PLANT-DEMOUNTABLE, ENGINE 1)
452AR
(2) FOR [4020KM2] (POWER PLANT-DEMOUNTABLE, ENGINE 2)
462AR

4. Procedure
Subtask 77-11-05-020-050-A

A. Removal of the N1 Sensor (7)
(1) Remove segment shroud 2 (Ref. AMM TASK 72-24-01-000-801).
(2) Remove the plate (1) as follows:
(a) Remove the bolt (4) that attaches the plate (1) to segment shroud 3 (3).
(b) Remove the four bolts (2) that attach the plate (1) to segment shroud 3 (3) and remove the plate (1).
(3) Disconnect the electrical connector (6) and electrical connector (9) from the N1 sensor (7) (Ref. AMM TASK 70-70-00-910-804).
(4) Remove the N1 sensor (7) as follows:

CAUTION: HANDLE THE N1 SPEED SENSOR CAREFULLY. THE SENSOR IS APPROXIMATELY 20 INCH (508 MM) LONG. DAMAGE TO THE SENSOR CAN OCCUR.

(a) Put a CONTAINER 5 L (1.32 USGAL) below the N1 sensor (7).

NOTE: A small quantity of oil can drain from the open port when you remove the N1 speed sensor (7).

(b) Loosen the two bolts (8) that attach the N1 sensor (7) to the fan hub frame (10).
(c) Remove the N1 sensor (7) from the fan hub frame (10).
(d) Remove and discard the preformed packing (5) from the N1 sensor (7).

Subtask 77-11-05-420-050-A

B. General
(1) Install COVER - PROTECTION and CAP - PROTECTION on all the open ports, open tubes, open hoses and connectors.

[Rev.10 from 2021] 2026.04.02 06:37:51 UTC