Removal of the Bosses [IAE]

TASK 72-50-50-000-801-A
Removal of the Bosses

ZONE: 400

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

REFERENCE	QTY	DESIGNATION
No specific	AR	ACCESS PLATFORM 2M (6 FT) - ADJUSTABLE
No specific	AR	WARNING NOTICE(S)

B. Work Zones and Access Panels

ZONE/ACCESS	ZONE DESCRIPTION
400	POWER PLANT, NACELLES AND PYLONS
FOR [1000EM1] (ENGINE-1)
437AL, 438AR
FOR [1000EM2] (ENGINE-2)
447AL, 448AR

C. Referenced Information

REFERENCE	DESIGNATION
TASK 71-13-00-010-010-A	Opening of the Fan Cowls 437AL(447AL),438AR(448AR)
TASK 78-11-11-000-010-A	Removal of the Common Nozzle Assembly
TASK 78-11-12-000-010-A	Removal of the Engine Exhaust Cone
TASK 78-30-00-040-012-A	Deactivation of the Thrust Reverser Hydraulic Control Unit (HCU) for Ground Maintenance
Bosses

3. Job Set-up
Subtask 72-50-50-941-052-A ** ON A/C NOT FOR ALL

A. Safety Precautions
(1) On the center pedestal, on 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 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 FADEC 1(2).

Subtask 72-50-50-010-060-A ** ON A/C NOT FOR ALL

B. Get Access
(1) Put the ACCESS PLATFORM 2M (6 FT) - ADJUSTABLE in position.
(2) 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 72-50-50-040-052-A ** ON A/C NOT FOR ALL

C. Deactivation of 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) Do the deactivation of the thrust reverser Hydraulic Control Unit (HCU) (Ref. AMM TASK 78-30-00-040-012).

Subtask 72-50-50-010-061-A ** ON A/C NOT FOR ALL

D. Remove the common nozzle assembly (Ref. AMM TASK 78-11-11-000-010).

Subtask 72-50-50-010-062-A ** ON A/C NOT FOR ALL

E. Remove the exhaust cone (Ref. AMM TASK 78-11-12-000-010).

4. Procedure
Subtask 72-50-50-020-058-A ** ON A/C NOT FOR ALL

A. Removal of the Bosses
(1) Remove the bolts (1) and the nuts (2).
(2) Remove the stop (3) from the boss (5).
(3) Remove the pins (4) from the boss (5).
(4) Remove the boss (5).

[Rev.10 from 2021] 2026.04.01 02:46:30 UTC