Removal of the Cold Buffer Air Tubes and No. 4 Bearing Scavenge Valve Air Tube [IAE]

TASK 75-22-49-000-801-A
Removal of the Cold Buffer Air Tubes and No. 4 Bearing Scavenge Valve Air Tube

WARNING: BE CAREFUL WHEN YOU DO WORK ON THE ENGINE PARTS AFTER THE ENGINE SHUTDOWN. USE APPLICABLE THERMAL GLOVES. THE ENGINE PARTS CAN STAY HOT FOR ONE HOUR AFTER SHUTDOWN AND CAN BURN YOU.

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 2M (6 FT) - ADJUSTABLE
No specific	AR	CAP - BLANKING
No specific	1	COVER - PROTECTION
No specific	AR	PLUG - BLANKING
No specific	AR	WARNING NOTICE(S)

B. Work Zones and Access Panels

ZONE/ACCESS	ZONE DESCRIPTION
FOR [1000EM1] (ENGINE-1)
437AL, 438AR, 451AL, 452AR
FOR [1000EM2] (ENGINE-2)
447AL, 448AR, 461AL, 462AR

C. Referenced Information

REFERENCE	DESIGNATION
TASK 71-13-00-010-010-A	Opening of the Fan Cowls 437AL(447AL),438AR(448AR)
TASK 75-24-51-000-010-B	Removal of the HPT/LPT ACC Air Valve
TASK 78-30-00-040-012-A	Deactivation of the Thrust Reverser Hydraulic Control Unit (HCU) for Ground Maintenance
TASK 78-32-00-010-010-A	Opening of the Thrust Reverser Halves
Cold Buffer Air Tubes
No.4 Bearing Scavenge Valve Air Tube

3. Job Set-up
Subtask 75-22-49-941-051-A ** ON A/C NOT FOR ALL

A. Safety Precautions
(1) On the center pedestal, on the ENG panel 115VU:
(a) Put a WARNING NOTICE(S) in position to tell persons not to start the engine.
(2) Make sure that the engine 1(2) shutdown occurred not less than five minutes before you do this procedure.
(3) On the overhead maintenance panel 50VU:
(a) Make sure that the ON legend of the ENG/FADEC GND PWR/1(2) pushbutton switch is off.
(b) Put a WARNING NOTICE(S) in position to tell persons not to energize the FADEC 1(2).

Subtask 75-22-49-010-052-A ** ON A/C NOT FOR ALL

B. Get Access
(1) Open the fan cowls (Ref. AMM TASK 71-13-00-010-010):
(a) FOR [1000EM1] (ENGINE-1)
437AL 438AR
(b) FOR [1000EM2] (ENGINE-2)
447AL 448AR.

Subtask 75-22-49-040-051-A ** ON A/C NOT FOR ALL

C. Deactivate the thrust reverser

WARNING: MAKE SURE THAT THE THRUST REVERSER HYDRAULIC CONTROL UNIT (HCU) IS DEACTIVATED BEFORE YOU DO WORK ON OR AROUND THE THRUST REVERSER. IF THE HCU IS NOT DEACTIVATED, THERE IS A RISK OF UNWANTED THRUST REVERSER OPERATION WHICH CAN CAUSE INJURY TO PERSONS AND/OR DAMAGE TO EQUIPMENT.

(1) Deactivate the thrust reverser Hydraulic Control Unit (HCU) (Ref. AMM TASK 78-30-00-040-012).

Subtask 75-22-49-010-053-A ** ON A/C NOT FOR ALL

D. Open the thrust reverser halves (Ref. AMM TASK 78-32-00-010-010):
(1) FOR [1000EM1] (ENGINE-1)
451AL 452AR
(2) FOR [1000EM2] (ENGINE-2)
461AL 462AR.
(3) Put the ACCESS PLATFORM 2M (6 FT) - ADJUSTABLE in position.

4. Procedure
Subtask 75-22-49-010-054-B ** ON A/C NOT FOR ALL

A. Remove the cold buffer air tube (3)

Cold Buffer Air Tubes ** ON A/C NOT FOR ALL

WARNING: USE PROTECTIVE GOGGLES AND GLOVES WHEN YOU REMOVE OR INSTALL LOCKWIRE. EACH TIME YOU CUT LOCKWIRE, REMOVE AND DISCARD IT IMMEDIATELY. LOOSE LOCKWIRE CAN CUT YOU OR MAKE YOU BLIND, AND/OR CAN CAUSE DAMAGE.

(1) Cut and discard the lockwire which is used to safety the cold buffer air tube (3) to the tee adaptor on the cold buffer air tube (2) and to the diffuser case adapter (4).
(2) Use a IAE1R18000 WRENCH and disconnect the cold buffer air tube (3) from the diffuser case adapter (4) and from the cold buffer air tube (2).
(3) Remove the bolt (6) and the washer (7) from the clip nut (11) on the bracket (10) to release the clip (8) at detail B.
(4) Remove the bolt (12) and the washer (13) from the clip nut (17) on the bracket (16) to release the clip (14) at detail C.
(5) Remove the bolt (18) and the washer (19) from the clip nut (23) on the bracket (22) to release the clip (20) at detail D.
(6) Remove the cold buffer air tube (3) from the engine.

Subtask 75-22-49-010-056-A ** ON A/C NOT FOR ALL

B. Remove the cold buffer air tube (1)

Cold Buffer Air Tubes ** ON A/C NOT FOR ALL

(1) Cut and discard the lockwire which is used to safety the cold buffer air tube (1) to the tee adaptor on the cold buffer air tube (2) and to the diffuser case adapter (5).
(2) Use a IAE1R18000 WRENCH and disconnect the cold buffer air tube (1) from the diffuser case adapter (5) and from the cold buffer air tube (2).
(3) Remove the cold buffer air tube (1) from the engine.

Subtask 75-22-49-010-057-A ** ON A/C NOT FOR ALL

C. Remove the cold buffer air tube (24).

Cold Buffer Air Tubes ** ON A/C NOT FOR ALL

(1) Remove the bolt (28), the washer (29) and the nut (31) that attach the clip (30) to the lug on the cold buffer air tube (24).
(2) Discard of the lockwire.

(a) Cut and discard the lockwire which is used to safety the cold buffer air tube (24) to the tee adaptor on the buffer air tube (2) and to the diffuser case adapter (25).
(3) Use a IAE1R18000 WRENCH and disconnect the cold buffer air tube (24) from the cold buffer air tube (2) and from the diffuser case adapter (25).
(4) Remove the air tube (24) from the engine.

Subtask 75-22-49-010-058-B ** ON A/C NOT FOR ALL

D. Remove the cold buffer air tube (2).

Cold Buffer Air Tubes ** ON A/C NOT FOR ALL

(1) Remove the HPT/LPT ACC air valve (Ref. AMM TASK 75-24-51-000-010).
(2) Make sure the cold buffer air tubes (1), (3) and (24) are disconnected.
(3) Remove the bolts (26) and the gasket (27) that attach the cold buffer air tube (2) to the No.4 bearing compartment cooler. Discard the gasket (27).
(4) Remove the bolt (32) and the washer (33) from the clip nut (37) on the bracket (36) to release the clip (34) at detail G.
(5) Remove the bolt (38) and the washer (39) from the clip nut (43) on the bracket (42) to release the clip (40) at detail H.
(6) Remove the bolt (44) and the washer (45) from the clip nut (49) on the bracket (48) to release the clip (46) at detail J.
(7) Remove the cold buffer air tube (2) from the engine.

Subtask 75-22-49-010-060-A ** ON A/C NOT FOR ALL

E. Remove the No.4 bearing scavenge valve air tube (1).

No.4 Bearing Scavenge Valve Air Tube ** ON A/C NOT FOR ALL

(1) Cut and discard the lockwire which is used to safety the No.4 bearing scavenge valve air tube (1) to the adaptor on the No.4 bearing scavenge valve air tube (2).
(2) Cut and discard the lockwire which is used to safety the No.4 bearing scavenge valve air tube (1) to the No.4 bearing compartment scavenge valve.
(3) Disconnect the No.4 bearing scavenge valve air tube (1) from the No.4 bearing scavenge valve air tube (2) and from the No.4 bearing compartment scavenge valve.
(4) Remove the bolt (3), the washer (4) and the nut (7) to release the clip (5) from the lug on the raceway (6) at detail B.
(5) Remove the bolt (8), the washer (10) and the nut (11) to release the clip (9) from the lug on the raceway (6) at detail C.
(6) Remove the bolt (12), the washer (13) and the nut (15) to release the clip (14) from the lug on the raceway (6) at detail D.
(7) Remove the air tube (1) from the engine.

Subtask 75-22-49-010-061-A ** ON A/C NOT FOR ALL

F. Put the applicable CAP - BLANKING, COVER - PROTECTION and PLUG - BLANKING on all the openings.

[Rev.10 from 2021] 2026.04.01 03:11:09 UTC