ADIRU 2 Bus Failure Channel A (External Fault)

TASK 73-00-00-810-944-A
ADIRU 2 Bus Failure Channel A (External Fault)

1. Possible Causes

[4000KS]

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
TSM TASK 73-00-00-810-941-A	ADIRU 1 Bus Failure Channel A (External Fault)
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 73-21-01-000-801	Removal of the Electronic Engine Control (EEC)
AMM 73-21-01-400-801	Installation of the Electronic Engine Control (EEC)
EEC Wiring Harnesses

3. Fault Confirmation
Subtask 73-00-00-710-386-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 Electronic Engine Control (EEC) self-test and this can cause spurious faults.

(3) On Multipurpose Control and Display Unit (MCDU) screen, make sure that the fault is displayed on ground scanning report.

NOTE: The EEC channel B has detected that the Air Data and Inertial Reference Unit (ADIRU) 1 Bus circuit has failed. This is currently being reported on the MCDU as ADIRU 2 BUS FAIL in this version of EEC software. The ADIRU 1 is located in the avionics compartment. The ADIRU 1 circuit is connected to the EEC channel A and cross-strapped to channel B within the EEC. The EEC is located on the fan case at the 2 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 73-00-00-810-298-A ** ON A/C NOT FOR ALL

A. Do a check on ground scanning report for the ADIRU 1 BUS FAIL fault on channel A
(1) If the ADIRU 1 BUS FAIL fault is on channel A, troubleshoot as per the fault on channel A (Ref. TSM TASK 73-00-00-810-941).
(2) If the ADIRU 1 BUS FAIL fault is NOT on channel A.
(a) Replace [4000KS] AMM 73-21-01-000-801 and AMM 73-21-01-400-801.
(b) Do the test given in Para. 3.

5. Close-up
Subtask 73-00-00-860-221-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.
(2) De-energize the aircraft electrical circuits
AMM 24-41-00-862-002.

[Rev.8 from Aug 2018] 2026.04.04 04:36:11 UTC