Removal of the ACT Pressurization Check Valve

TASK 28-28-38-000-001-A
Removal of the ACT Pressurization Check Valve

WARNING: BE CAREFUL NOT TO GET AIRCRAFT FUEL IN YOUR MOUTH OR IN YOUR EYES. IF YOU GET FUEL ON YOUR SKIN OR ON YOUR CLOTHES, FLUSH IT IMMEDIATELY WITH WATER. IF NECESSARY, GET MEDICAL HELP. AIRCRAFT FUEL IS POISONOUS.

WARNING: DO NOT GET YOUR CLOTHES SOAKED WITH FUEL.

WARNING: MAKE SURE THAT YOU HAVE THE CORRECT FIRE FIGHTING EQUIPMENT AVAILABLE.

WARNING: OBEY THE FUEL SAFETY PROCEDURES.

FIN: 178QM ** 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 2M (6 FT)
No specific	AR	PLUG - BLANKING
No specific	AR	SAFETY CLIP - CIRCUIT BREAKER
No specific	1	WARNING NOTICE(S)

B. Work Zones and Access Panels

ZONE/ACCESS	ZONE DESCRIPTION
151BC

C. 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 25-55-11-000-002-A	Removal of the Ceiling Panels in the Aft Cargo-Compartment - FR47/FR59
TASK 28-00-00-910-001-A	Fuel Safety Procedures
TASK 52-30-00-860-001-A	Open the FWD or Aft Cargo-Compartment Door with the Yellow Electric Pump
ACT Pressurization Check Valve

3. Job Set-up
Subtask 28-28-38-860-050-A ** 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) Energize the aircraft electrical circuits
(Ref. AMM TASK 24-41-00-861-002).
(3) Put a WARNING NOTICE(S) in position on the panels that follow:

Refuel/defuel panel 801VU
Fuel panel 28VU and 40VU
to tell persons not to operate the refuel/defuel system.

Subtask 28-28-38-010-051-A ** ON A/C NOT FOR ALL

B. Get Access
(1) Open the aft cargo-compartment door (Ref. AMM TASK 52-30-00-860-001).
(2) Put an ACCESS PLATFORM 2M (6 FT) in position at the opening of the aft cargo compartment.
(3) In the aft cargo compartment, remove cargo ceiling panel 151BC (Ref. AMM TASK 25-55-11-000-002).

Subtask 28-28-38-865-050-A ** ON A/C NOT FOR ALL

C. Open, safety and tag this(these) circuit breaker(s):

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C NOT FOR ALL
121VU	ACT1/REFUEL & SPLY	33QU	L29
121VU	FUEL/HI/LVL/SPLY	1QJ	L25
121VU	FUEL/RFL/DFL/SPLY	2QU	L24
121VU	FUEL/RFL/DFL/XFR/DEFUEL/VALVE	1QU	L23
121VU	ACT XFR VALVE MAN CTL	30QH	N29
121VU	ACT1/CTL & SPLY	9QH	P29
121VU	ACT PUMP SUPPLY	25QH	Q29

4. Procedure
Subtask 28-28-38-020-050-A ** ON A/C NOT FOR ALL

A. Removal of the ACT Pressurization Check-Valve
(1) Loosen the union nut (2) from the check valve (4) and remove the pipe (3).
(2) Loosen the union nut (5) of the check valve (4).
(3) Remove the check valve (4) from the T-pipe section (6).
(4) Put the PLUG-BLANKING in each disconnected line end.

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