Removal of the Gearbox Vent Tube

TASK 49-26-55-000-801-A
Removal of the Gearbox Vent Tube

WARNING: DO NOT TOUCH THE APU UNTIL IT IS SUFFICIENTLY COOL TO PREVENT BURNS WHEN YOU DO THE MAINTENANCE TASK(S).

1. Reason for the Job
Self explanatory
2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment

REFERENCE	QTY	DESIGNATION
No specific	1	ACCESS PLATFORM 5M (16 FT)- ADJUSTABLE
No specific	AR	SAFETY CLIP - CIRCUIT BREAKER
No specific	AR	WARNING NOTICE(S)

B. Work Zones and Access Panels

ZONE/ACCESS	ZONE DESCRIPTION
315AL, 316AR

C. Referenced Information

REFERENCE	DESIGNATION
TASK 24-41-00-861-002-A	Energize the Aircraft Electrical Circuits from the External Power
TASK 24-41-00-861-002-A-01	Energize the Aircraft Electrical Circuits from the APU
TASK 24-41-00-861-002-A-02	Energize the Aircraft Electrical Circuits from Engine 1(2)
TASK 29-00-00-864-001-A	Put the Related Hydraulic System in the Depressurized Configuration before Maintenance Action
TASK 52-41-00-010-001-A	Open the APU Doors for Access
Gearbox Vent Tube

3. Job Set-up
Subtask 49-26-55-860-050-A ** ON A/C NOT FOR ALL

A. Aircraft Maintenance Configuration
(1) Energize the aircraft electrical circuits
(Ref. AMM TASK 24-41-00-861-002).
(2) On panel 25VU, make sure that the APU MASTER SW p/bsw is in the OFF position.
(3) Put the WARNING NOTICE(S) on panel 25VU to tell persons not to start the APU.
(4) Make sure that the hydraulic systems are depressurized
(Ref. AMM TASK 29-00-00-864-001).

Subtask 49-26-55-865-050-A ** ON A/C NOT FOR ALL

B. Open, safety and tag this(these) circuit breaker(s):

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C NOT FOR ALL
121VU	APU/APU/CTL	2KD	L42
121VU	APU/ECB/SPLY	1KD	L41

Subtask 49-26-55-010-050-A ** ON A/C NOT FOR ALL

C. Get Access
(1) Put the ACCESS PLATFORM 5M (16 FT)- ADJUSTABLE in position below APU access doors 315AL and 316AR.
(2) Open APU access doors 315AL and 316AR (Ref. AMM TASK 52-41-00-010-001).
(3) Set light switch 11LJ to the ON position.

4. Procedure
Subtask 49-26-55-020-051-A ** ON A/C NOT FOR ALL

A. Removal of the Gearbox Vent Tube

CAUTION: WHEN YOU REMOVE/INSTALL THE PARTS, BE CAREFUL NOT TO HIT THE COMPONENTS ADJACENT TO THE APU. DAMAGE TO THESE COMPONENTS CAN OCCUR.

(1) Remove the retainer bolt (4) from the air/oil separator adapter (3).
(2) Disconnect the gearbox vent tube (1) from the union fitting (6).

CAUTION: YOU MUST USE TWO WRENCHES AND HOLD THE COMPONENT WHEN YOU REMOVE/INSTALL THE PIPE COUPLINGS AND/OR UNIONS. THIS PREVENTS DAMAGE TO THE COMPONENT.

(a) Loosen the nut (5) to disconnect the gearbox vent tube (1) from the union fitting (6).
(3) Release the grommets of the wiring harness from the clamps of the gearbox vent tube (1).

NOTE: It is not necessary to release the grommets of the wiring harness from the clamps of the APU.

(4) Release the grommets of the gearbox vent tube (1) from the clamps of the APU to remove the gearbox vent tube (1).
(5) Remove the packings (2) from the gearbox vent tube (1).
(6) Examine the packings (2) for cuts, tears or broken pieces, and discard if damaged.
(7) Remove the union fitting (6) from the turbine bearing housing.

[Rev.10 from 2021] 2026.04.01 01:29:17 UTC