Installation of the ACT Pressurization Check Valve

TASK 28-28-38-400-002-A
Installation of the ACT Pressurization Check Valve

WARNING: OBEY THE FUEL SAFETY PROCEDURES.

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.

ZONE: 150
FIN: 178QM ** ON A/C NOT FOR ALL

1. Reason for the Job
Self explanatory
2. Job Set-up Information
A. Work Zones and Access Panels

ZONE/ACCESS	ZONE DESCRIPTION
150	AFT CARGO COMPARTMENT FWD PRESS BULKHEAD TO AFT BULKHEAD OF AFT CARGO COMPARTMENT
151BC, 826

B. 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 24-41-00-862-002-A	De-energize the Aircraft Electrical Circuits Supplied from the External Power
TASK 24-41-00-862-002-A-01	De-energize the Aircraft Electrical Circuits Supplied from the APU
TASK 24-41-00-862-002-A-02	De-energize the Aircraft Electrical Circuits Supplied from the Engine 1(2)
TASK 25-55-11-000-002-A	Removal of the Ceiling Panels in the Aft Cargo-Compartment - FR47/FR59
TASK 25-55-11-400-002-A	Installation of the Ceiling Panels in the Aft Cargo-Compartment - FR47/FR59
TASK 28-00-00-910-001-A	Fuel Safety Procedures
TASK 28-28-00-710-005-A	Operational Test of the Additional Center Tank (ACT) Automatic Transfer System
TASK 52-30-00-860-001-A	Open the FWD or Aft Cargo-Compartment Door with the Yellow Electric Pump
TASK 52-30-00-860-002-A	Close the FWD or Aft Cargo-Compartment Door with the Yellow Electric Pump
ACT Pressurization Check Valve

3. Job Set-up
Subtask 28-28-38-860-054-B ** ON A/C NOT FOR ALL

A. Aircraft Maintenance Configuration
(1) Obey the fuel safety procedures (Ref. AMM TASK 28-00-00-910-001).
(2) Make sure that the aircraft electrical circuits are energized.
(Ref. AMM TASK 24-41-00-861-002).
(3) Make sure that the WARNING NOTICE(S) are on control panels that follow, to tell persons not to operate the refuel/defuel system:

Refuel/defuel panels 800VU and 801VU
Fuel control panel 40VU
Additional Center Tank (ACT) control panel 28VU.

(4) Make sure that the ACCESS PLATFORM 2M (6 FT) is below aft cargo compartment door 826.
(5) Make sure that aft cargo-compartment door 826 is open (Ref. AMM TASK 52-30-00-860-001).
(6) Make sure that CARGO COMPT LIGHT switch 8LU is in the ON position.
(7) Make sure that in the aft cargo-compartment, cargo ceiling panel 151BC is removed (Ref. AMM TASK 25-55-11-000-002).

Subtask 28-28-38-865-054-A ** ON A/C NOT FOR ALL

B. Make sure that this(these) circuit breaker(s) is(are) open, safetied and tagged:

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C NOT FOR ALL
121VU	FUEL/ACT AIR SOV/MAN/SPLY	64QH	J20
121VU	FUEL/ACT AIR SOV/AUTO/SPLY	63QH	J19
121VU	FUEL/ACT XFR VLV/MOT2	66QH	J18
121VU	FUEL/ACT XFR VLV/MOT1	65QH	J17
121VU	FUEL/HI/LVL/SPLY	1QJ	L24
121VU	FUEL/RFL/DFL/SPLY	2QU	L23
121VU	FUEL/RFL/DFL/XFR/DEFUEL/VALVE	1QU	L22
121VU	FUEL/ACT VENT VLV/MAN/SPLY	62QH	L21
121VU	FUEL/ACT VENT VLV/AUTO/SPLY	61QH	L20
121VU	FUEL/ACT/FUEL PUMP/SPLY	25QH	Q29

4. Procedure
Subtask 28-28-38-420-051-B ** ON A/C NOT FOR ALL

A. Installation of the ACT Pressurization Check Valve
(1) Remove the PLUG-BLANKING from each disconnected line end.
(2) Clean the component interfaces and the adjacent area.
(3) Do an inspection of the component interfaces and the adjacent area.
(4) Make sure that the parts retained from the removed component are clean and in the correct condition.
(5) Put the check valve (3) in position and install the union nut (4) on the T-pipe section (5).
(6) Install the union nut (1) on the check valve (3).

CAUTION: USE A SECOND WRENCH TO HOLD THE FITTINGS WHEN YOU LOOSEN/TIGHTEN THE TUBE COUPLING NUTS. THIS PREVENTS DAMAGE TO THE TUBES.

(7) Tighten the union nuts (1) and (4).

Subtask 28-28-38-865-055-A ** ON A/C NOT FOR ALL

B. Remove the safety clip(s) and the tag(s) and close this(these) circuit breaker(s):

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C NOT FOR ALL
121VU	FUEL/ACT AIR SOV/MAN/SPLY	64QH	J20
121VU	FUEL/ACT AIR SOV/AUTO/SPLY	63QH	J19
121VU	FUEL/ACT XFR VLV/MOT2	66QH	J18
121VU	FUEL/ACT XFR VLV/MOT1	65QH	J17
121VU	FUEL/HI/LVL/SPLY	1QJ	L24
121VU	FUEL/RFL/DFL/SPLY	2QU	L23
121VU	FUEL/RFL/DFL/XFR/DEFUEL/VALVE	1QU	L22
121VU	FUEL/ACT VENT VLV/MAN/SPLY	62QH	L21
121VU	FUEL/ACT VENT VLV/AUTO/SPLY	61QH	L20
121VU	FUEL/ACT/FUEL PUMP/SPLY	25QH	Q29

Subtask 28-28-38-710-051-A ** ON A/C NOT FOR ALL

C. Test
(1) Do the operational test of the ACT automatic transfer system (Ref. AMM TASK 28-28-00-710-005).

5. Close-up
Subtask 28-28-38-410-050-B ** ON A/C NOT FOR ALL

A. Close Access
(1) Make sure that the work area is clean and clear of tools and other items.
(2) In the aft cargo-compartment, install cargo ceiling panel 151BC (Ref. AMM TASK 25-55-11-400-002).
(3) Set CARGO COMPT LIGHT switch 8LU to the OFF position.
(4) Remove the access platform(s).
(5) Close aft cargo-compartment door 826 (Ref. AMM TASK 52-30-00-860-002).

Subtask 28-28-38-860-055-A ** ON A/C NOT FOR ALL

B. Put the aircraft back to the serviceable condition.
(1) On refuel/defuel control panels 800VU and 801VU, on fuel control panel 40VU and on ACT control panel 28VU:
(a) Remove the WARNING NOTICE(S).
(2) De-energize the aircraft electrical circuits
(Ref. AMM TASK 24-41-00-862-002).

[Rev.10 from 2021] 2026.04.02 06:17:57 UTC