Removal of the Buffer Air Heat Exchanger [PW11]

TASK 75-26-01-000-801-A
Removal of the Buffer Air Heat Exchanger

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 INSTRUCTION, INJURY CAN OCCUR.

ZONE: 400
FIN: 4100JM ** ON A/C NOT FOR ALL

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 1M(3 FT)
No specific	AR	COVER - PROTECTION

B. Work Zones and Access Panels

ZONE/ACCESS	ZONE DESCRIPTION
400	POWER PLANT, NACELLES AND PYLONS
FOR [4020KM1] (POWER PLANT-DEMOUNTABLE, ENG 1)
437AL, 438AR, 451AL
FOR [4020KM2] (POWER PLANT-DEMOUNTABLE, ENG 2)
447AL, 448AR, 461AL

C. Referenced Information

REFERENCE	DESIGNATION
TASK 71-00-00-860-833-A	Procedure to Prevent Engine Motoring
TASK 71-13-00-010-802-A	Opening of the Fan Cowl Doors
TASK 78-30-00-040-805-A	Deactivation of the Thrust Reverser System for Ground Maintenance
TASK 78-36-00-010-802-A	Opening of the Thrust Reverser Cowl-Doors
Buffer Air Heat Exchanger

3. Job Set-up
Subtask 75-26-01-941-050-A ** ON A/C NOT FOR ALL

A. Safety Precautions
(1) Do the procedure to prevent engine motoring
(Ref. AMM TASK 71-00-00-860-833).

Subtask 75-26-01-010-050-A ** ON A/C NOT FOR ALL

B. Get Access
(1) Open the fan cowl doors (Ref. AMM TASK 71-13-00-010-802):
(a) FOR [4020KM1] (POWER PLANT-DEMOUNTABLE, ENG 1)
437AL 438AR
(b) FOR [4020KM2] (POWER PLANT-DEMOUNTABLE, ENG 2)
447AL 448AR
(2) Put an ACCESS PLATFORM 1M(3 FT) in position.

Subtask 75-26-01-040-050-A ** ON A/C NOT FOR ALL

C. Deactivation of the Thrust Reverser for Maintenance

WARNING: YOU MUST DEACTIVATE THE THRUST REVERSER BEFORE YOU DO WORK ON OR AROUND IT. IF YOU DO NOT, THE THRUST REVERSER CAN OPERATE ACCIDENTALLY AND CAUSE AN INJURY AND/OR DAMAGE.

(1) Do the deactivation of the thrust reverser system for maintenance (Ref. AMM TASK 78-30-00-040-805).

Subtask 75-26-01-010-051-A ** ON A/C NOT FOR ALL

D. Get Access
(1) Open the left thrust reverser cowl-door (Ref. AMM TASK 78-36-00-010-802):
(a) FOR [4020KM1] (POWER PLANT-DEMOUNTABLE, ENG 1)
451AL
(b) FOR [4020KM2] (POWER PLANT-DEMOUNTABLE, ENG 2)
461AL

4. Procedure

CAUTION: WIPE CLEAN ALL PARTS AND TOOLS AS NECESSARY TO REMOVE UNWANTED DEBRIS AND PREVENT DAMAGE TO THE ENGINE.

Subtask 75-26-01-020-050-A ** ON A/C NOT FOR ALL

A. Removal of the Buffer Air Heat Exchanger
(1) Find the buffer air heat exchanger (1) at the 10 o'clock position.
See Sheet 1 of the figure:

Buffer Air Heat Exchanger ** ON A/C NOT FOR ALL

(2) Remove the tube (AD07) (4) from the heat exchanger (1) as follows:
(a) Remove the two bolts (6) that attach the clamp (5) and the tube (AD07) (4) to the bracket.
(b) Remove the coupling (3) that attaches the tube (AD07) (4) to the heat exchanger (1).
(c) Remove the tube (AD07) (4).
(d) Remove and discard the gasket (2).
(3) Disconnect the manifolds (AP24), (AP27) and the tube (AD06) from the heat exchanger (1) as follows:
See Sheet 2 of the figure:

Buffer Air Heat Exchanger ** ON A/C NOT FOR ALL

(a) Remove the six bolts (16) from the two manifolds (AP24), (AP27) and the bracket.
(b) Remove the coupling (19) that attaches the tube (AD06) to the heat exchanger (1).
(4) Remove the heat exchanger (1) from the engine as follows:
See Sheet 3 of the figure:

Buffer Air Heat Exchanger ** ON A/C NOT FOR ALL

(a) Remove the two bolts (31) and the aft pin (30) that attach the heat exchanger (1) to the center bracket assembly.
(b) Remove the two bolts (32) that attach the heat exchanger (1) to the rear bracket assembly.
(c) Remove the heat exchanger (1) from the forward bracket assembly.
(d) Remove the two bolts (31) and the forward pin (30) from the heat exchanger (1), if necessary.
(e) Remove the metering plate (18).
See Sheet 2 of the figure:

Buffer Air Heat Exchanger ** ON A/C NOT FOR ALL

(f) Remove and discard the two gaskets (17) and the gasket (20).
(5) If necessary, remove the bracket (41) and the two bolts (42).
See Sheet 4 of the figure:

Buffer Air Heat Exchanger ** ON A/C NOT FOR ALL

(6) Installation of the protection covers:

CAUTION: INSTALL PROTECTION COVERS ON ALL THE OPENINGS IMMEDIATELY TO PREVENT DAMAGE TO THE ENGINE.

(a) Make sure that you install COVER - PROTECTION as necessary to prevent damage to the engine.

[Rev.10 from 2021] 2026.04.01 13:02:06 UTC