Installation of the Refuel Diffuser Assembly - Center Tank

TASK 28-25-42-400-002-A
Installation of the Refuel Diffuser Assembly - Center Tank

WARNING: THIS PROCEDURE USES A FUEL SYSTEM ITEM THAT IS IN A CATEGORY KNOWN AS A CRITICAL DESIGN CONFIGURATION CONTROL LIMITATION (CDCCL). CDCCL IDENTIFIES AN ITEM THAT CAN BE THE SOURCE OF A POSSIBLE FUEL TANK IGNITION. YOU MUST KEEP ALL CDCCL ITEMS IN THE APPROVED CONFIGURATION. DAMAGE, WEAR OR CHANGES TO A CDCCL ITEM CAN CAUSE A POSSIBLE FUEL TANK EXPLOSION.

WARNING: MAKE SURE THAT THE FLIGHT CONTROL SAFETY-LOCKS AND THE WARNING NOTICES ARE IN POSITION.

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: BE CAREFUL WHEN YOU USE CONSUMABLE MATERIALS. OBEY THE MATERIAL MANUFACTURER'S INSTRUCTIONS AND YOUR LOCAL REGULATIONS.

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 5M (16 FT)- ADJUSTABLE
No specific	AR	SAFETY BARRIER(S)
No specific	AR	WARNING NOTICE(S)

B. Consumable Materials

REFERENCE	DESIGNATION
(Material No.01ABA1)	Turbine Fuel-- Kerosene -
(Material No.03FAB1)	Mineral Oil base Grease-- Vaseline or Petrolatum -
(Material No.06ABA1)	Polysulfide Sealant-Fuel Tank Brushable -
(Material No.08BAA9)	Non Aqueous Cleaner-General - -
(Material No.14SBA1)	Textile-Lint free Cotton -

C. Work Zones and Access Panels

ZONE/ACCESS	ZONE DESCRIPTION
148AZ

D. Expendable Parts

FIG.ITEM	DESIGNATION	IPC-CSN
5	O-RING	AIPC 28-25-05-02-230
5	O-RING	AIPC 28-25-85-02-040

E. Referenced Information

REFERENCE	DESIGNATION
TASK 12-11-28-650-003-A	Pressure Refuel with Automatic Control
TASK 20-28-00-912-802-A	Electrical Bonding - General Maintenance Procedure
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 28-25-00-869-001-A	Fuel Transfer
TASK 32-12-00-010-001-A	Open the Main Gear Doors for Access
TASK 32-12-00-410-001-A	Close the Main Gear Doors after Access
TASK 57-17-11-000-001-A	Removal of Access Cover 147AZ(148AZ)
TASK 57-17-11-000-001-B	Removal of Access Cover 148AZ or/and the ACT-Equipment Support Door
TASK 57-17-11-400-001-A	Installation of Access Cover 147AZ(148AZ)
TASK 57-17-11-400-001-B	Installation of Access Cover 148AZ or/and the ACT-Equipment Support-Door
Refuel Diffuser Assembly, Center Tank.

3. Job Set-up
Subtask 28-25-42-941-055-A

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) As necessary, use the applicable SAFETY BARRIERS, specified by the operator's instructions and your local regulations.
(3) Make sure that the WARNING NOTICE(S) is in position to tell persons not to operate the MLG doors.

Subtask 28-25-42-860-053-A ** ON A/C NOT FOR ALL

B. Aircraft Maintenance Configuration
(1) Make sure that the center tank is defueled (Ref. AMM TASK 28-25-00-650-001).
(2) Make sure that the remaining fuel has been drained from the center tank (Ref. AMM TASK 28-25-00-650-003).
(3) Make sure that the ACCESS PLATFORM 5M (16 FT)- ADJUSTABLE is in position below the access panel 148AZ.
(4) Make sure that the RH MLG door is open (Ref. AMM TASK 32-12-00-010-001).
(5) Make sure that the 460005835 SLEEVE - GROUND LOCK is installed on the RH MLG door actuating-cylinder.
(6) Make sure that the access panel 148AZ is removed (Ref. AMM TASK 57-17-11-000-001), (Ref. AMM TASK 28-10-00-910-002).

Subtask 28-25-42-860-053-C ** ON A/C NOT FOR ALL

Subtask 28-25-42-865-054-A

C. 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/RFL/DFL/SPLY	2QU	L24
121VU	FUEL/RFL/DFL/XFR/DEFUEL/VALVE	1QU	L23
** ON A/C NOT FOR ALL
121VU	FUEL/RFL/DFL/SPLY	2QU	L23
121VU	FUEL/RFL/DFL/XFR/DEFUEL/VALVE	1QU	L22

4. Procedure
Subtask 28-25-42-420-053-A

A. Preparation for Installation
(1) Use a clean Textile-Lint free Cotton - (Material No.14SBA1) made moist with Non Aqueous Cleaner-General - - (Material No.08BAA9) to clean:

the interface of the diffuser assembly (9)
the bonding lug
the bolts (3), (7) and (11)
the washers (4), (8) and (10)
the end of the bonding strip (1)
the interface of the support brackets.

(2) Make sure that the parts retained from the removed component are clean and in the correct condition.
(3) Do an inspection of the component interfaces and the adjacent area.
(4) Lubricate the new AIPC 28-25-05-02-230 O-RING (5) or AIPC 28-25-85-02-040 O-RING (5) with Turbine Fuel-- Kerosene - (Material No.01ABA1) or Mineral Oil base Grease-- Vaseline or Petrolatum - (Material No.03FAB1) .

Subtask 28-25-42-420-051-A

B. Installation of the Refuel Diffuser Assembly - Center Tank
(1) Install the restrictor (6) and the O-ring (5) in the diffuser assembly (9).

NOTE: You must bond one each of the bolts (7) and (11) (Ref. AMM TASK 20-28-00-912-802).

(2) Put the diffuser assembly (9) in position and install the washers (8) and (10) and the bolts (7) and (11).
(3) Make sure that one of the bolts (7) and one of the bolts (11) are correctly bonded:

WARNING: THIS INSTRUCTION IS APPLICABLE TO A CRITICAL DESIGN CONFIGURATION CONTROL LIMITATION (CDCCL) ITEM. CAREFULLY OBEY ALL GIVEN INSTRUCTIONS WHEN YOU DO THIS STEP. IF YOU DO NOT OBEY THESE INSTRUCTIONS, A DANGEROUS CONDITION CAN OCCUR THAT CAN CAUSE A POSSIBLE FUEL TANK EXPLOSION.

(a) Do a bonding check of one of the bolts (7) and one of the bolts (11) (Ref. AMM TASK 20-28-00-912-802). The bonding resistance must be less than 10 milliohms.
(4) Put the pipe assembly in position on the diffuser assembly (9) and tighten the nut (2).
(5) Install the bonding strip (1) on the bonding lug with the washer (4) and the bolt (3) (Ref. AMM TASK 20-28-00-912-802).
(6) Make sure that the bonding strip (1) is correctly bonded to the diffuser assembly (9):
(a) Do a bonding check between the bonding strip (1) and the diffuser assembly (9) (Ref. AMM TASK 20-28-00-912-802). The bonding resistance must be less than 10 milliohms.
(7) Apply Polysulfide Sealant-Fuel Tank Brushable - (Material No.06ABA1) to:

the bolts (3), (7) and (11)
the washers (4), (8) and (10)
the end of the bonding strip (1)
the bottom surface of the bonding lug.

5. Close-up
Subtask 28-25-42-410-052-A ** 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) Install the access panel 148AZ (Ref. AMM TASK 57-17-11-400-001).
(3) Remove the access platform(s).
(4) Close the RH MLG door (Ref. AMM TASK 32-12-00-410-001).

Subtask 28-25-42-410-052-C ** ON A/C NOT FOR ALL

Subtask 28-25-42-650-054-A

B. Fuel Configuration
(1) Refuel, defuel or transfer fuel as necessary (Ref. AMM TASK 12-11-28-650-003), (Ref. AMM TASK 28-25-00-650-001) or (Ref. AMM TASK 28-25-00-869-001).

Subtask 28-25-42-942-051-A

C. Removal of Equipment
(1) Remove the safety barriers.
(2) Remove the WARNING NOTICE(S).
(3) Remove the ground support and maintenance equipment, the special and standard tools and all other items.

[Rev.10 from 2021] 2026.04.02 06:17:40 UTC