Removal of the Pressure-Holding Valve

TASK 28-16-41-000-001-A
Removal of the Pressure-Holding Valve

WARNING: PUT THE SAFETY DEVICES AND THE WARNING NOTICES IN POSITION BEFORE YOU START A TASK ON OR NEAR:

THE FLIGHT CONTROLS
THE FLIGHT CONTROL SURFACES
THE LANDING GEAR AND THE RELATED DOORS
COMPONENTS THAT MOVE.

MOVEMENT OF COMPONENTS CAN KILL OR CAUSE INJURY TO PERSONS AND/OR CAN CAUSE DAMAGE TO THE EQUIPMENT.

WARNING: MAKE SURE THAT THE GROUND SAFETY-LOCKS ARE IN POSITION ON THE LANDING GEAR. THIS WILL PREVENT UNWANTED MOVEMENT OF THE LANDING GEAR, AND THUS POSSIBLE INJURY TO PERSONS AND DAMAGE TO THE AIRCRAFT AND/OR EQUIPMENT.

FIN: 124QM ** ON A/C NOT FOR ALL
FIN: 125QM ** 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	AR	ACCESS PLATFORM 3M (10 FT)
No specific	AR	SAFETY BARRIER(S)

B. Work Zones and Access Panels

ZONE/ACCESS	ZONE DESCRIPTION
FOR [124QM] (VALVE-PRESSURE HOLDING, L WING TANK)
540MB
FOR [125QM] (VALVE-PRESSURE HOLDING, R WING TANK)
640MB

C. Referenced Information

REFERENCE	DESIGNATION
TASK 28-10-00-910-001-A	Safety Procedures When You Do Work in a Fuel Tank
TASK 28-10-00-910-002-A	Access to the Fuel Tanks and the Work Areas
TASK 28-25-00-650-001-A	Pressure Defuel
TASK 28-25-00-650-003-A	To Drain Remaining Fuel from the Wing Tanks and the Center Tank
TASK 28-25-00-650-003-A-01	To Drain Remaining Fuel from the Wing Tanks and the Center Tank
TASK 57-27-11-000-002-A	Removal of the Access Panel
Pressure Holding Valve

3. Job Set-up
Subtask 28-16-41-941-052-A ** ON A/C NOT FOR ALL

A. Safety Precautions

WARNING: BEFORE YOU DO WORK IN OR NEAR A FUEL TANK, MAKE SURE THAT YOU OBEY ALL THE SAFETY PROCEDURES. THIS WILL PREVENT INJURY TO PERSONS AND/OR DAMAGE TO THE AIRCRAFT.

(1) You must obey the fuel safety procedures (Ref. AMM TASK 28-10-00-910-001) when you do work in a fuel tank.
(2) Put the SAFETY BARRIER(S) in position.

Subtask 28-16-41-860-050-A ** ON A/C NOT FOR ALL

B. Fuel Configuration
(1) Defuel the applicable fuel tank (Ref. AMM TASK 28-25-00-650-001).
(2) Drain the remaining fuel from the applicable fuel tank (Ref. AMM TASK 28-25-00-650-003).

Subtask 28-16-41-010-050-A ** ON A/C NOT FOR ALL

C. Get Access
(1) Put the ACCESS PLATFORM 3M (10 FT) below the applicable zone 540(640).
(2) Remove the applicable access panel (Ref. AMM TASK 28-10-00-910-002), (Ref. AMM TASK 57-27-11-000-002):

(a) FOR [124QM] (VALVE-PRESSURE HOLDING, L WING TANK)
remove 540MB
(b) FOR [125QM] (VALVE-PRESSURE HOLDING, R WING TANK)
remove 640MB.

4. Procedure
Subtask 28-16-41-020-050-A ** ON A/C NOT FOR ALL

A. Removal of the Pressure Holding Valve 124QM(125QM)
(1) Remove the bolts (2) and remove the pressure holding valve (3).
(2) Remove and discard the O-ring (1).

[Rev.10 from 2021] 2026.04.02 06:17:17 UTC