IDG FOC Clogged (in Bypass)

TASK 73-21-00-810-898-A
IDG FOC Clogged (in Bypass)

1. Possible Causes

IDG1 FUEL/OIL HEAT EXCHANGER [5001XM1]
IDG2 FUEL/OIL HEAT EXCHANGER [5001XM2]
SENSOR-DIFF PRESS, IDG FUEL/OIL HEAT [9XT]

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 12-32-28-281-003	Sample Fuel for Microbiological Contamination Analysis
AMM 24-21-42-000-802	Removal of the IDG Fuel/Oil Heat-Exchanger
AMM 24-21-42-000-804	Removal of the AC Generator Fuel/Oil Differential Pressure-Sensor
AMM 24-21-42-400-802	Installation of the IDG Fuel/Oil Heat-Exchanger
AMM 24-21-42-400-804	Installation of the AC Generator Fuel/Oil Differential Pressure-Sensor
AMM 24-41-00-861-002	Energize the Aircraft Electrical Circuits from the External Power
AMM 24-41-00-862-002	De-energize the Aircraft Electrical Circuits Supplied from the External Power
AMM 71-13-00-010-802	Opening of the Fan Cowl Doors
AMM 71-13-00-410-802	Closing of the Fan Cowl Doors
AMM 73-11-00-210-805	General Visual Inspection of the Fuel Distribution System for Contamination
Engine Fuel/Oil Heat Exchanger

3. Fault Confirmation
Subtask 73-21-00-710-151-A ** ON A/C NOT FOR ALL

A. Energize the FADEC of the engine that has a fault report.
(1) Energize the aircraft electrical circuits AMM 24-41-00-861-002.
(2) On the ENG section of maintenance panel 50VU:
(a) Release the FADEC GND PWR/1(2) pushbutton switch (the ON legend comes on).

NOTE: After the FADEC is energized, wait ten seconds before you start the test. If you do not wait ten seconds, the interactive mode stops the EEC self-test and this can cause spurious faults.

(3) On MCDU screen, check if the fault is displayed on ground scanning report.

NOTE: The Electronic Engine Control (EEC) has detected the pressure sensor monitoring the AC generator fuel/oil heat exchanger is indicating the heat exchanger is in bypass. The AC generator fuel/oil heat exchanger is mounted on the oil manifold at the 9 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) If the maintenance message does not come back, examine the harnesses and electrical connectors as described in the component and harness intermittent fault isolation procedure (Ref. TSM TASK 71-00-00-810-835).
(a) If no problems are found, return the engine to service. Monitor the engine for reoccurring maintenance message.
(5) If the maintenance message comes back (hard fault), go to the Para. Fault Isolation.

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 73-21-00-810-170-A ** ON A/C NOT FOR ALL

A. If there is confirmation of the fault:
(1) Open the fan cowl doors AMM 71-13-00-010-802.
(2) Replace IDG1 FUEL/OIL HEAT EXCHANGER [5001XM1] or IDG2 FUEL/OIL HEAT EXCHANGER [5001XM2] AMM 24-21-42-000-802 and AMM 24-21-42-400-802.
(a) Examine the removed IDG fuel/oil heat exchanger (5001XM) for contamination.
1 If contamination is found in the IDG fuel/oil heat exchanger, go to the step 4.A.(3).
2 If contamination is not found, do the test given in Para. 3.
a If the fault continues:

Go to the step 4.A.(4).

(3) Do a check of the fuel system for contamination AMM 73-11-00-210-805 and AMM 12-32-28-281-003.
(a) Repair any problems found.
(b) Do the test given in Para. 3.
(4) If the fault continues:
(a) Replace SENSOR-DIFF PRESS, IDG FUEL/OIL HEAT [9XT] AMM 24-21-42-000-804 and AMM 24-21-42-400-804.
(b) Do the test given in Para. 3.

5. Close-up
Subtask 73-21-00-860-090-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 fan cowl doors AMM 71-13-00-410-802.
(b) De-energize the aircraft electrical circuits AMM 24-41-00-862-002.

[Rev.8 from Aug 2018] 2026.04.04 04:41:16 UTC