Functional Check for Leakage of the ACT Pressurization System

TASK 28-28-00-790-803-A
Functional Check for Leakage of the ACT Pressurization System

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: 130
ZONE: 150

1. Reason for the Job
Refer to the MPD TASK: 282800-23
FUNCTIONAL CHECK FOR LEAKAGE OF THE ACT PRESSURIZATION SYSTEM.
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	1	AIR SOURCE 0.3 TO 0.7 BAR (5 TO 10 PSI)- FILTERED, DRY
No specific	1	GAGE 5 BAR (75 PSI) - PRESSURE
No specific	AR	PLUG - BLANKING
No specific	AR	SAFETY CLIP - CIRCUIT BREAKER
No specific	AR	WARNING NOTICE(S)
No specific	Torque wrench: range to between 0.06 and 0.055 m.daN (5.31 and 4.87 lbf.in )
No specific	Torque wrench: range to between 4.3 and 3.9 m.daN (31.71 and 28.76 lbf.ft )
98D28108658000	1	TOOL-PRESSURE TEST,ACT

B. Work Zones and Access Panels

ZONE/ACCESS	ZONE DESCRIPTION
130	FWD CARGO COMPT AFT BULKHEAD OF AVNCS COMPT TO FWD PRESSURE BULKHEAD OF WING CENTER BOX
150	AFT CARGO COMPARTMENT FWD PRESS BULKHEAD TO AFT BULKHEAD OF AFT CARGO COMPARTMENT
151NC, 192MB, 197AB, 826

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 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 25-55-11-400-002-A	Installation of the Ceiling Panels in the Aft Cargo-Compartment - FR47/FR59
TASK 28-00-00-910-001-A	Fuel Safety Procedures
TASK 28-11-27-000-003-A	Removal of the Additional Center Tank No.2 (ACT AFT2)
TASK 28-11-27-400-003-A	Installation of the Additional Center Tank No.2 (ACT AFT2)
TASK 28-25-00-650-001-A	Pressure Defuel
TASK 28-25-00-650-005-A	To Drain the Remaining Fuel from the Additional Center Tank (ACT)
TASK 33-14-00-710-001-A	Operational Check of the Light Test 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
TASK 53-22-12-000-001-A	Removal of the Cabin Floor Panels
TASK 53-22-12-400-001-A	Installation of the Cabin Floor Panels
TASK 53-35-13-000-001-A	Removal of the Belly Fairing Access Panels
TASK 53-35-13-400-001-A	Installation of the Belly Fairing Access Panels
TASK 06-41-53-00	FUSELAGE-DESCRIPTION AND OPERATION
Access to Test Ports T1 and T2
Test Tool Arrangement ACT
Access to Test Ports T1 and T2
Datum pipe guard
ACT Inlet Check Valve
Pressurization Check valves

3. Job Set-up
Subtask 28-28-00-860-255-A ** ON A/C NOT FOR ALL

A. Aircraft Maintenance Configuration
(1) Obey the fuel safety procedure (Ref. AMM TASK 28-00-00-910-001).
(2) Energize the aircraft electrical circuits
(Ref. AMM TASK 24-41-00-861-002).
(3) Defuel all the Additional Center Tank(s) (ACT(s)) (Ref. AMM TASK 28-25-00-650-001).
(4) Drain the remaining fuel from the applicable ACT(s) (Ref. AMM TASK 28-25-00-650-005).
(5) On the right side of the belly fairing, open quick-release access-door 192MB.
(6) On refuel/defuel control panels 800VU and 801VU, make sure that:

The MODE SELECT switch is in the OFF position
All the REFUEL VALVE switches are in the NORM position.

(7) Put a WARNING NOTICE(S) in position on refuel/defuel control panels 800VU and 801VU:

To tell persons not to operate the refuel/defuel system.

(8) On the right side of the belly fairing, close quick-release access-door 192MB.

Subtask 28-28-00-865-190-A ** ON A/C NOT FOR ALL

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

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C NOT FOR ALL
121VU	FUEL/ACT/FUEL PUMP/SPLY	25QH	Q29

Subtask 28-28-00-010-130-A ** ON A/C NOT FOR ALL

C. Get Access
(1) Open the forward and aft cargo-compartment doors (Ref. AMM TASK 52-30-00-860-001).
(2) Put an ACCESS PLATFORM 2M (6 FT) - ADJUSTABLE in position at aft cargo-compartment door 826.
(3) If installed, remove ACT AFT2 from the aft cargo compartment (Ref. AMM TASK 28-11-27-000-003).
(4) For Test port T1 and T2:
(a) Open ceiling panel 151NC (1) to get access to test ports T1 and T2.

Access to Test Ports T1 and T2 ** ON A/C NOT FOR ALL

1 Loosen the studs (2) and open the access panel (1).
(5) For check valve 231QM4:
(a) In the forward cabin compartment, remove cabin floor panel 231BMG to get access to the ACT FWD (Ref. AMM D/O 06-41-53-00) (Ref. AMM TASK 53-22-12-000-001).

NOTE: Removal of the floor panel is only necessary if the ACT FWD is installed.

(b) Open the applicable maintenance panel on cargo ceiling panels above the ACT(s).
(6) For the datum pipe guard:
(a) Remove access panel 197AB from the belly fairing (Ref. AMM TASK 53-35-13-000-001).

4. Procedure
Subtask 28-28-00-860-256-A ** ON A/C NOT FOR ALL

A. Preparation for the Test

Pressurization Check valves ** ON A/C NOT FOR ALL

(1) In the cockpit, close the ACT air shut-off valve actuator (90QH):
(a) On the ACT control panel 28VU:

Make sure the ACT XFR rotary switch to OFF position.
Make sure that the "MAN" legend in the "MOD SEL" pushbutton switch is off.

(2) Connect to 98D28108658000 TOOL-PRESSURE TEST,ACT test ports T1 and T2.
(3) Connect an AIR SOURCE 0.3 TO 0.7 BAR (5 TO 10 PSI)- FILTERED, DRY and a GAGE 5 BAR (75 PSI) - PRESSURE to test port T1.
(4) Remove the datum pipe guard (1) from the belly fairing.

CAUTION: USE A SECOND WRENCH TO APPLY COUNTERTORQUE TO THE UNION WHEN YOU DISCONNECT/CONNECT EQUIPMENT FROM FLEXIBLE HOSES AND RIGID TUBING. IF YOU DO NOT USE THE SECOND WRENCH, THERE IS A RISK THAT YOU WILL CAUSE DAMAGE TO THE HOSES AND TUBES.

(5) Disconnect the pressure lines (3) of check valves 231QM1 (ACT AFT1) and 231QM4 (ACT AFT4):
(a) Loosen the union nuts (4) and disconnect the pressure lines (3) from the elbow unions (5).
(6) Put the PLUG-BLANKING in each disconnected line end.

Subtask 28-28-00-790-059-A ** ON A/C NOT FOR ALL

WARNING: WHEN YOU USE COMPRESSED AIR:

USE THE CORRECT PROTECTION (FACE SHIELD OR GOGGLES)
DO NOT POINT THE AIRFLOW AT YOURSELF OR OTHER PERSONS.

LOOSE PARTICLES AND/OR HIGH PRESSURE AIR CAN CAUSE INJURY.

B. Functional Check for the Leakage of the ACT Pressurization System .

ACTION	RESULT
1.Do a check of check valve 179QM, the pipe connections and air-shutoff-valve actuator 90QH:
Slowly apply a pressure between 0.483 bar (7 psi) and 0.552 bar (8 psi) through test port T1.
Stop the pressurization.	On the pressure gage at test port T1: The air pressure is stable between 0.483 bar (7 psi) and 0.552 bar (8 psi) for more than 15 minutes On the pressure gage at test port T2, the pressure is constant at 0 bar (0 psi).
2.Release the pressure from all the pipelines.	On the pressure gage at test port T1, the pressure decreases to 0 bar (0 psi).
3.Do a check of check valve 178QM:
Open air shut-off valve 233QM: Do an operational test of the annunciator-light test system in the cockpit (Ref. AMM TASK 33-14-00-710-001) Make sure that all the lights on ACT FUEL control panel 28VU are on during the test On ACT FUEL control-panel 28VU, make sure that the ACT XFR rotary switch is in the OFF position Push the MOD SEL pushbutton switch Make sure that the MAN legend in the MOD SEL pushbutton switch is on. NOTE: The ACT air shutoff-valve (233QM) is open at this time.
Increase the pressure through test port T1 between 0.483 bar (7.0053 psi) and 0.552 bar (8.0061 psi).	On the pressure gage at test port T1: Pressure increases between 0.483 bar (7 psi) and 0.552 bar (8 psi). On the pressure gage at test port T2: Pressure decreases between 0.320 bar (4.64 psi) and 0.475 bar (6.89 psi).
4.Stop the pressurization.	At test ports T1 and T2: Pressure stays constant for more than 15 minutes.
5.Bleed air from test port T1 to atmosphere.	At test port T2: The pressure does not decrease for more than 15 minutes.
6.If the pressure decreases, use a soap solution or a leak detector spray to find the leaks.	Make sure that there are no leaks. If there are leaks, do an approved repair and do this test again.
7.Release the pressure from all the pipelines.	On the pressure gage at test port T1 pressure stays 0 bar (0.00 psi).

Subtask 28-28-00-860-257-A ** ON A/C NOT FOR ALL

C. Put the aircraft back to its initial configuration.

Pressurization Check valves ** ON A/C NOT FOR ALL

(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) Connect the pressure lines (3) of check valves 231QM1 (ACT AFT1) and 231QM4 (ACT AFT4):

CAUTION: USE TWO WRENCHES TO REMOVE OR INSTALL THE HOSE NUTS. USE ONE WRENCH TO HOLD THE FITTING AND ONE WRENCH TO LOOSEN OR TIGHTEN THE HOSE NUT. IF YOU DO NOT DO THIS, DAMAGE TO THE COMPONENTS CAN OCCUR.

CAUTION: MAKE SURE THAT THE FLEXIBLE HOSES ARE NOT TWISTED OR PULLED TIGHT. IF THE HOSES ARE TWISTED OR PULLED TIGHT, THE CONNECTIONS WILL BREAK AND CAUSE A LEAK.

(a) Connect the union nuts (4) to the pressure lines (3).
(b) Put the pressure lines (3) in position.
(c) TORQUE the union nuts (4) to between 4.3 and 3.9 m.daN (31.71 and 28.76 lbf.ft )

NOTE: The fuel movement from the ACT to the center tank will not work if the air hose is not correctly connected to the ACT pressurization system.

(5) Install the datum pipe guard (1) to the belly fairing.
(6) Make sure that in the cockpit the air shut-off valve 233QM is open.

5. Close-up
Subtask 28-28-00-410-091-A ** ON A/C NOT FOR ALL

A. Close Access
(1) Install belly fairing access panel 197AB (Ref. AMM TASK 53-35-13-400-001).
(2) Close the access to test ports T1 and T2:
(a) Put the access panel (1) in position and loosely install the studs (2).
(b) TORQUE the studs (2) to between 0.06 and 0.055 m.daN (5.31 and 4.87 lbf.in )

.
(3) In the aft cargo compartment, close cargo ceiling panel 151NC (Ref. AMM TASK 25-55-11-400-002).
(4) If removed, install cabin floor panels 231BMG in the forward cabin compartment (Ref. AMM TASK 53-22-12-400-001).
(5) If removed, install ACT AFT2 in the aft cargo compartment (Ref. AMM TASK 28-11-27-400-003).
(6) Close the forward and aft cargo-compartment doors (Ref. AMM TASK 52-30-00-860-002).

Subtask 28-28-00-865-189-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/FUEL PUMP/SPLY	25QH	Q29

Subtask 28-28-00-860-258-A ** ON A/C NOT FOR ALL

C. Put the aircraft back to its initial configuration.
(1) Remove the WARNING NOTICE(S).
(2) Remove the ground support and maintenance equipment, the special and standard tools and all other items.
(3) Make sure that the work area is clean and clear of tools and other items.
(4) De-energize the aircraft electrical circuits
(Ref. AMM TASK 24-41-00-862-002).

[Rev.10 from 2021] 2026.04.02 06:17:52 UTC