Removal of the ADIRU Mount (Alternative Procedure)

TASK 34-12-51-000-802-A
Removal of the ADIRU Mount (Alternative Procedure)

CAUTION: AFTER YOU REMOVE THE ADIRU MOUNT, DO NOT PUT PRESSURE OR OBJECTS ON ITS SUPPORT, WHICH IS EASILY DAMAGED. IF YOU DO NOT OBEY THIS PRECAUTION, YOU CAN CAUSE DAMAGE TO THE SUPPORT.

ZONE: 120

1. Reason for the Job
Use this procedure as an alternative to the nominal procedure of the ADIRU mount removal when one of the conditions that follow occurs:

Important damage on structure and aircraft skin between FR20 and FR24A
Flight-crew tech-log entry during the last flight related to the IR, AFS or EFCS
Failure detected or warning triggered during the last flight related to the IR, AFS or EFCS
Aircraft not installed with criteria MPM 25753P4280 or SB 34-1123 which installs wiring between ADIRU3 and the DMU (attitude and true heading angles of ADIRU3 are not available)
The criteria related to the pitch, roll or true heading in the nominal procedure are not applicable.

2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment

REFERENCE	QTY	DESIGNATION
No specific	AR	CAP - BLANKING

B. Work Zones and Access Panels

ZONE/ACCESS	ZONE DESCRIPTION
120	AVIONICS COMPARTMENT
127BG

C. Referenced Information

REFERENCE	DESIGNATION
TASK 21-26-41-000-001-A	Removal of the Check Valve
TASK 21-26-42-000-001-A	Removal of the Avionics Equipment Ventilation-Duct
TASK 21-26-43-000-003-A	Removal of the Filter Assembly
TASK 21-26-43-000-006-A	Removal of the Filter Assembly
TASK 21-26-43-000-007-A	Removal of the Filter Assembly
TASK 25-71-00-000-801-A	Removal of the Umbrella Assembly
TASK 34-12-34-000-001-A	Removal of the ADIRU
TASK 34-12-51-400-001-A	Installation of the ADIRU Mount with Alignment Tools
TASK 53-12-13-000-001-A	Removal of the avionics compartment floor panels
ADIRU Mount ** ON A/C NOT FOR ALL
ADIRU Mount ** ON A/C NOT FOR ALL
ADIRU Mount ** ON A/C NOT FOR ALL

3. Job Set-up
Subtask 34-12-51-210-055-A

A. Preparation for the Subsequent Mount Installation

Make sure that the the tools necessary for the mount installation are available (Ref. AMM TASK 34-12-51-400-001).

Subtask 34-12-51-020-058-C

B. Get Access
(1) Remove the umbrella assembly (Ref. AMM TASK 25-71-00-000-801).
(2) Remove aft avionics-compartment floor-panel 127BG (Ref. AMM TASK 53-12-13-000-001).

Subtask 34-12-51-020-054-A

C. Remove ADIRUs 1FP1, 1FP2 and 1FP3 (Ref. AMM TASK 34-12-34-000-001).

4. Procedure
Subtask 34-12-51-020-055-A ** ON A/C NOT FOR ALL

CAUTION: AFTER YOU REMOVE THE ADIRU MOUNT, DO NOT PUT PRESSURE OR OBJECTS ON ITS SUPPORT, WHICH IS EASILY DAMAGED. IF YOU DO NOT OBEY THIS PRECAUTION, YOU CAN CAUSE DAMAGE TO THE SUPPORT.

A. Removal of the ADIRU Mount

ADIRU Mount ** ON A/C NOT FOR ALL

(1) Remove the nuts (4), washers (8) and screws (7) which attach the bonding leads (5) to the mount (13).
(2) Remove the nuts (14) from the screws (11).
(3) Remove the electrical connectors (12) from the mount (13). Use some straps to attach the electrical connectors (12).
(4) Put the CAP-BLANKING on each disconnected electrical connector and receptacle.
(5) Remove the nuts (1), washers (2) and screws (6).
(6) Lift the mount (13) off its support. Be careful not to cause damage to the peel shims (3) and the air conditioning pipe (9).
(7) Put marks on the peel shims (3) with a felt-tip pen or equivalent, to make sure that you put them back in their initial positions when you install the mount (13).

NOTE: The peel shims below the mount and their related positions must be clearly identified to put them back in their initial positions.

(8) Remove the nuts (10).
(9) Remove the air conditioning pipe (9).
(10) Remove the mount (13).

Subtask 34-12-51-020-055-B ** ON A/C NOT FOR ALL

CAUTION: AFTER YOU REMOVE THE ADIRU MOUNT, DO NOT PUT PRESSURE OR OBJECTS ON ITS SUPPORT, WHICH IS EASILY DAMAGED. IF YOU DO NOT OBEY THIS PRECAUTION, YOU CAN CAUSE DAMAGE TO THE SUPPORT.

A. Removal of the ADIRU Mount

ADIRU Mount ** ON A/C NOT FOR ALL

(1) Remove the screws (9) and the washers (8) which attach the bonding leads (7) to the mount (2).
(2) Remove the screws (12) from the electrical connectors (14).
(3) Remove the plates (13) and the electrical connectors (14) from the mount (2). Use some straps to attach the electrical connectors (14).
(4) Put the CAP-BLANKING on each disconnected electrical connector and receptacle.
(5) Remove the nuts (6), washers (5) and bolts (3).
(6) Remove the nuts (10), the washers (11) and the bolts (1).
(7) Lift the mount (2) off its support. Be careful not to cause damage to the peel shims (4).
(8) Put marks on the peel shims (4) with a felt-tip pen or equivalent, to make sure that you put them back in their initial positions when you install the mount (2).

NOTE: The peel shims below the mount and their related positions are clearly identified to put them back in their initial positions.

(9) Remove the mount (2).

Subtask 34-12-51-020-056-B

B. Removal of the Air Conditioning Pipes
(1) Remove the check valve (2140HM) (If installed) (Ref. AMM TASK 21-26-41-000-001).
(2) Remove the filter assembly (2081HM, 2082HM, 2083HM) (If installed) (Ref. AMM TASK 21-26-43-000-002) or (Ref. AMM TASK 21-26-43-000-006) or (Ref. AMM TASK 21-26-43-000-007).
(3) Remove the avionics equipment ventilation-duct (Ref. AMM TASK 21-26-42-000-001).

5. Close-up
Subtask 34-12-51-860-051-A

A. Do the installation of the ADIRU mount with alignment tools (Ref. AMM TASK 34-12-51-400-001).

[Rev.10 from 2021] 2026.04.02 07:14:04 UTC