FDGS Aux Pump Failure

TASK 72-15-00-810-801-A
FDGS Aux Pump Failure

1. Possible Causes

SENSOR-PRESSURE, AUXILIARY OIL [4070KS]
POWER PLANT-DEMOUNTABLE [4020KM]

2. Job Set-up Information
A. Referenced Information

REFERENCE	DESIGNATION
TSM TASK 71-00-00-810-834-A	General Troubleshooting Guidelines for Additional Troubleshooting Information
TSM TASK 71-00-00-810-835-A	Component and Harness Intermittent Troubleshooting Procedure for Guidance Troubleshooting Intermittent Faults
AMM 71-00-00-720-816	Test No. 17 - Above Idle Test
AMM 71-00-51-000-802	Removal of the Power Plant (Bootstrap Method)
AMM 71-00-51-400-802	Installation of the Power Plant (Bootstrap Method)
AMM 78-36-00-010-802	Opening of the Thrust Reverser Cowl-Doors
AMM 78-36-00-410-802	Closing of the Thrust Reverser Cowl-Doors
AMM 79-00-00-281-802	Inspection of the Magnetic Chip Collectors for Oil Contamination
AMM 79-33-24-000-801	Removal of the Auxiliary Oil Pressure (AOP) Sensor
AMM 79-33-24-400-801	Installation of the Auxiliary Oil Pressure (AOP) Sensor
Auxiliary Oil Pressure Sensor Wiring Harness

3. Fault Confirmation
Subtask 72-15-00-710-050-A ** ON A/C NOT FOR ALL

A. Not Applicable

NOTE: The Electronic Engine Control (EEC) is reporting that the fan drive gearbox auxiliary pump has failed to produce a minimum oil pressure. The fan drive gearbox auxiliary pump pressure is monitored by the auxiliary oil pressure sensor which provides input to the Prognostics and Health Management Unit (PHMU) above a specific N1 speed. The PHMU provides information to both channel A and channel B of the EEC. The auxiliary oil pressure sensor is located on the Variable Oil Reduction Valve (VORV)/journal oil shuttle valve manifold at the 3 o'clock position. The fan drive gearbox auxiliary pump is mounted in the fan drive gearbox, located at the 8 o'clock position.

Refer to the general troubleshooting guidelines for additional troubleshooting information (Ref. TSM TASK 71-00-00-810-834).
Refer to the component and harness intermittent troubleshooting procedure for guidance troubleshooting intermittent faults (Ref. TSM TASK 71-00-00-810-835).

4. Fault Isolation

WARNING: BE CAREFUL WHEN YOU DO WORK ON THE ENGINE AFTER SHUTDOWN. THE ENGINE CAN STAY HOT FOR A LONG TIME. IF YOU DO NOT OBEY THIS WARNING, INJURY CAN OCCUR.

WARNING: REFER TO THE MSDS FOR ALL MATERIAL USED AND THE MANUFACTURER'S SAFETY INSTRUCTIONS FOR ALL EQUIPMENT USED. IF YOU DO NOT OBEY THIS WARNING, INJURY CAN OCCUR.

CAUTION: MAKE SURE YOU REMOVE ELECTRICAL POWER FROM THE EEC BEFORE YOU REMOVE THE ELECTRICAL CONNECTORS. IF YOU DO NOT OBEY THIS INSTRUCTION, DAMAGE TO THE EEC CAN OCCUR.

Subtask 72-15-00-810-050-A ** ON A/C NOT FOR ALL

A. Do the steps that follow:
(1) Open the thrust reverser cowl-doors AMM 78-36-00-010-802.
(2) Do a check of the No. 1 and No. 1.5 bearing compartment chip collector AMM 79-00-00-281-802.
(a) If the magnetic chip collector inspection is not OK, remove the engine from service.
(b) If the magnetic chip collector inspection is OK, go to the next step.
(3) Replace SENSOR-PRESSURE, AUXILIARY OIL [4070KS] AMM 79-33-24-000-801 and AMM 79-33-24-400-801.
(a) Go to the Para. 4.B.
(4) If the fault continues:
(a) Replace POWER PLANT-DEMOUNTABLE [4020KM] AMM 71-00-51-000-802 and AMM 71-00-51-400-802.

NOTE: The engine must be removed from service to access and replace the fan drive gearbox auxiliary pump.

(b) Go to the Para. 4.B.

Subtask 72-15-00-710-051-A ** ON A/C NOT FOR ALL

B. Repair Confirmation
(1) Run the engine to 75% N1 and shut down AMM 71-00-00-720-816. Look at the ground scanning report to confirm the repair of this fault.

5. Close-up
Subtask 72-15-00-860-050-A ** ON A/C NOT FOR ALL

A. Put the aircraft back to its initial configuration.
(1) Make sure that the work area is clean and clear of tools and other items.
(a) Close the thrust reverser cowl-doors AMM 78-36-00-410-802.

[Rev.8 from Aug 2018] 2026.04.04 04:35:10 UTC