Electrical Test of the No. 1 Bearing Vibration Sensor [CFMI]

TASK 77-31-10-720-002-A
Electrical Test of the No. 1 Bearing Vibration Sensor

FIN: 1000EM1 ** ON A/C NOT FOR ALL
FIN: 1000EM2 ** ON A/C NOT FOR ALL

1. Reason for the Job
To make sure that the No. 1 bearing vibration sensor is serviceable before a fan trim balance or a vibration test. If the sensor is not serviceable at the end of this adjustment/test procedure, the engine stays serviceable and permits the subsequent flights. Use the vibration indications from the TRF vibration sensor. But, remove and replace the sensor at the first engine shop visit.
2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment

REFERENCE	QTY	DESIGNATION
No specific	AR	MEGOHMMETER 100 MOHMS
No specific	AR	PLIERS - CONNECTOR, JAW, SOFT
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 71-00-00-000-040-A	Removal of the Power Plant
TASK 71-00-00-000-040-A-01	Removal of the Power Plant with the Engine Positioner TWW 75E
TASK 71-00-00-000-040-A-03	Removal of the Power Plant with Jacxson Tool
TASK 71-00-00-400-040-A	Installation of the Power Plant
TASK 71-00-00-400-040-A-01	Installation of the Power Plant with the Engine Positioner TWW 75E
TASK 71-00-00-400-040-A-03	Installation of the Power Plant with Jacxson Tool
TASK 71-13-00-010-040-A	Opening of the Fan Cowl Doors
TASK 71-13-00-410-040-A	Closing of the Fan Cowl Doors
TASK 77-31-00-040-801-A	Deactivation of the No. 1 Bearing Vibration Sensor
No. 1 Bearing Vibration Sensor

3. Job Set-up
Subtask 77-31-10-941-050-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 77-31-10-010-050-A ** ON A/C NOT FOR ALL

B. Open the fan cowl doors (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 77-31-10-720-050-A ** ON A/C NOT FOR ALL

A. Electrical Test of the No. 1 Bearing Vibration Sensor.
(1) Disconnect the aircraft harness from the No. 1 bearing vibration sensor connector. Use PLIERS - CONNECTOR, JAW, SOFT, only if necessary.
(2) Measure the insulation resistance (on the connector) with a MEGOHMMETER 100 MOHMS set to the 50 volt DC scale between:
(a) Pins 1 and 2
(b) Pins 1 and 3
(c) Pin 1 and connector body
(d) Pin 2 and connector body
(e) Pin 3 and connector body
(3) The insulation resistance must be more than 20 megohms. If any one of these measurements is less than 20 megohms, the sensor is not serviceable.
(a) If the sensor is not serviceable, replace the No. 1 bearing vibration sensor in shop (Ref. AMM TASK 71-00-00-000-040) (Ref. AMM TASK 71-00-00-400-040) or deactivate the No. 1 bearing vibration sensor (Ref. AMM TASK 77-31-00-040-801).
(4) Make sure that the aircraft harness connector and the sensor receptacle connector are clean and clear of unwanted material.
(5) Connect the aircraft harness to the No. 1 bearing vibration sensor connector. Fully tighten by hand.

5. Close-up
Subtask 77-31-10-410-050-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 03:16:54 UTC