Removal of the ACT Overpressure Protector

TASK 28-12-42-000-001-A
Removal of the ACT Overpressure Protector

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.

WARNING: OBEY THE FUEL SAFETY PROCEDURES.

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.

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: 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: 141
ZONE: 142
FIN: 256QM ** 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	1	CONTAINER 5 L (1.32 USGAL)
No specific	1	PLUG - BLANKING
No specific	AR	SAFETY CLIP - CIRCUIT BREAKER
No specific	AR	WARNING NOTICE(S)

B. Work Zones and Access Panels

ZONE/ACCESS	ZONE DESCRIPTION
141	WING CENTER BOX
142	WING CENTER BOX
147AZ

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 28-00-00-910-001-A	Fuel Safety Procedures
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 32-12-00-010-001-A	Open the Main Gear Doors for Access
TASK 57-17-11-000-001-B	Removal of Access Cover 148AZ or/and the ACT-Equipment Support Door
ACT Overpressure Protector (256QM, 257QM)

3. Job Set-up
Subtask 28-12-42-941-050-A ** ON A/C NOT FOR ALL

A. Safety Precautions
(1) You must obey the fuel safety procedures when you do work on the fuel system (Ref. AMM TASK 28-00-00-910-001).
(2) Energize the aircraft electrical circuits
(Ref. AMM TASK 24-41-00-861-002).
(3) On the APU section of overhead panel 25VU, make sure that the MASTER SW pushbutton switch is released (the ON legend is off).
(4) On the FUEL section of fuel panel 40VU, make sure that all the L TK PUMPS and R TK PUMPS pushbutton switches are released (the OFF legends are on).
(5) Put the WARNING NOTICE(S) in position:

On the APU section of overhead panel 25VU, to tell persons not to operate the MASTER SW pushbutton switch
On the FUEL section of fuel panel 40VU, to tell persons not to operate the fuel system
On ENG/APU FIRE panel 1WD installed on overhead panel 20VU, to tell persons not to operate the fire extinguishing system.

(6) Put the WARNING NOTICE(S) in position to tell persons not to operate the main gear doors.

Subtask 28-12-42-650-050-A ** ON A/C NOT FOR ALL

B. Defuel the center tank (Ref. AMM TASK 28-25-00-650-001).

Subtask 28-12-42-865-050-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
49VU	FUEL/FQI/CHAN/1	1QT	A13
49VU	ALSCU SPLY	66QJ	B10
49VU	AFMC SPLY	3QN	B08
121VU	FUEL/ACT RFL/VLV/SPLY & CTL	43QU	J21
121VU	FUEL/ACT XFR VLV/MOT2	66QH	J18
121VU	FUEL/ACT XFR VLV/MOT1	65QH	J17
121VU	FUEL/ALSCU/HI LEVEL/SPLY	64QJ	K21
121VU	FUEL/ALSCU/SPLY	65QJ	K20
121VU	FUEL/AFMC/SPLY	4QN	K19
121VU	FUEL/FQI/CHANNEL/1 AND 2	8QT	L25
121VU	FUEL/ACT VENT VLV/MAN/SPLY	62QH	L21
121VU	FUEL/ACT VENT VLV/AUTO/SPLY	61QH	L20
121VU	FUEL/FQI/CHAN/2	2QT	M27
121VU	FUEL/ACT/FUEL PUMP/SPLY	25QH	Q29
121VU	FUEL/RFL/ON BAT	5QN	R30

Subtask 28-12-42-010-050-A ** ON A/C NOT FOR ALL

D. Get Access
(1) Open the right MLG door (Ref. AMM TASK 32-12-00-010-001).
(2) Put an ACCESS PLATFORM 2M (6 FT) in position at the right MLG door.
(3) Get access to the fuel center tank (Ref. AMM TASK 28-10-00-910-002).
(4) Remove access cover 147AZ (Ref. AMM TASK 57-17-11-000-001).

4. Procedure
Subtask 28-12-42-020-051-A ** ON A/C NOT FOR ALL

A. Removal of the ACT Overpressure Protector
(1) Put a CONTAINER 5 L (1.32 USGAL) below the ACT overpressure protector (1).
(2) Remove the nuts (2) and the bolts (3).
(3) Remove the ACT overpressure protector (1) from the machined tee.
(4) Put the PLUG - BLANKING on the disconnected line ends.

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