Installation of the Refuel Diffuser Assembly - Wing Tanks

TASK 28-25-42-400-001-A
Installation of the Refuel Diffuser Assembly - Wing Tanks

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	SAFETY BARRIER(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
540JB, 540KB, 640JB, 640KB
540HB, 640HB

D. Expendable Parts

FIG.ITEM	DESIGNATION	IPC-CSN
3	O-RING	AIPC 28-25-05-28-120
5	O-RING	AIPC 28-25-05-28-120
5	O-RING	AIPC 28-25-85-28-300

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 28-00-00-000-001-A	Removal of the Fuel Pipes
TASK 28-00-00-400-001-A	Installation of the Fuel Pipes
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 57-27-11-000-002-A	Removal of the Access Panel
TASK 57-27-11-400-002-A	Installation of the Access Panel
Refuel Diffuser Assembly - Wing Tanks ** ON A/C NOT FOR ALL
Refuel Diffuser Assembly - Wing Tanks ** ON A/C NOT FOR ALL

3. Job Set-up
Subtask 28-25-42-941-054-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) Make sure that the SAFETY BARRIER(S)S are in position.

Subtask 28-25-42-865-051-A

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/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

Subtask 28-25-42-860-052-A ** ON A/C NOT FOR ALL

C. Aircraft Maintenance Configuration
(1) Make sure that the applicable fuel tank is defueled (Ref. AMM TASK 28-25-00-650-001).
(2) Make sure that the remaining fuel has been drained from the applicable fuel tank (Ref. AMM TASK 28-25-00-650-003).
(3) Make sure that the access platform is below the applicable zone 540 (640).
(4) Make sure that the applicable access panels 540JB (640JB), 540KB (640KB) are removed (Ref. AMM TASK 28-10-00-910-002), (Ref. AMM TASK 57-27-11-000-002).
(5) Make sure that the pipe assembly is removed (Ref. AMM TASK 28-00-00-000-001).

Subtask 28-25-42-860-052-B ** ON A/C NOT FOR ALL

C. Aircraft Maintenance Configuration
(1) Make sure that the applicable fuel tank is defueled (Ref. AMM TASK 28-25-00-650-001) .
(2) Make sure that the remaining fuel has been drained from the applicable fuel tank (Ref. AMM TASK 28-25-00-650-003).
(3) Make sure that the access platform is below the applicable access panel 540HB (640HB).
(4) Make sure that the applicable access panel 540HB (640HB) is removed (Ref. AMM TASK 28-10-00-910-002), (Ref. AMM TASK 57-27-11-000-002).

4. Procedure
Subtask 28-25-42-420-052-A ** ON A/C NOT FOR ALL

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 (8)
the bonding lug
the bolts (4) and (7) and the washers (6)
the screw (1), the nut (3)
the end of the bonding strip (2)
the interface of the support bracket assembly and the support angle assembly.

(2) Do an inspection of the component interfaces and the adjacent area.
(3) Make sure that the parts retained from the removed component are clean and in the correct condition.
(4) Lubricate the new AIPC 28-25-05-28-120 O-RING (5) or AIPC 28-25-85-28-300 O-RING (5) with Turbine Fuel-- Kerosene - (Material No.01ABA1) or Mineral Oil base Grease-- Vaseline or Petrolatum - (Material No.03FAB1) .

Subtask 28-25-42-420-052-B ** ON A/C NOT FOR ALL

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 (2)
the bonding lug
the bolts (5) and (6)
the bolt (1) and the nut (7)
the end of the bonding strap (8)
the interface of the support brackets and the diffuser (2).

(2) Do an inspection of the component interfaces and the adjacent area.
(3) Make sure that the parts retained from the removed component are clean and in the correct condition.
(4) Lubricate the new AIPC 28-25-05-28-120 O-RING (3) with Turbine Fuel-- Kerosene - (Material No.01ABA1) or Mineral Oil base Grease-- Vaseline or Petrolatum - (Material No.03FAB1) .

Subtask 28-25-42-420-050-E ** ON A/C NOT FOR ALL

B. Installation of the Refuel Diffuser Assembly - Wing Tanks
(1) Install the O-ring (5) in the connector.

NOTE: You must bond one each of the bolts (4) and (7) (Ref. AMM TASK 20-28-00-912-802).

(2) Put the diffuser (8) in position and install the washers (6) and the bolts (4) and (7).
(3) Make sure that one of the bolts (4) and one of the bolts (7) 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 (4) and one of the bolts (7) (Ref. AMM TASK 20-28-00-912-802). The bonding resistance must be less than 10 milliohms.
(4) Attach the bonding strip (2) to the bonding lug with the screw (1) and the nut (3) (Ref. AMM TASK 20-28-00-912-802).
(5) Make sure that the bonding strip (2) is correctly bonded to the diffuser (8):
(a) Do a bonding check between the bonding strip (2) and the diffuser (8) (Ref. AMM TASK 20-28-00-912-802). The bonding resistance must be less than 10 milliohms.
(6) Apply Polysulfide Sealant-Fuel Tank Brushable - (Material No.06ABA1) to:

the ends of the bonding strip (2)
the screw (1)
the nut (3)
the bolts (4) and (7).

Subtask 28-25-42-420-050-F ** ON A/C NOT FOR ALL

B. Installation of the Refuel Diffuser Assembly - Wing Tanks
(1) Install the O-ring (3) on the pipe (4).
(2) Put the diffuser (2) in position on the pipe (4).

NOTE: You must bond one each of the bolts (5) and (6) (Ref. AMM TASK 20-28-00-912-802).

(3) Install the bolts (5) and the bolts (6).
(4) Make sure that one of the bolts (5) and one of the bolts (6) are correctly bonded:

(a) Do a bonding check of one of the bolts (5) and one of the bolts (6) (Ref. AMM TASK 20-28-00-912-802). The bonding resistance must be less than 10 milliohms.
(5) Attach the bonding strap (8) to the diffuser with the bolt (1) and the nut (7) (Ref. AMM TASK 20-28-00-912-802).
(6) Make sure that the bonding strap (8) is correctly bonded to the diffuser (2):
(a) Do a bonding check between the bonding strap (8) and the diffuser (2) (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 ends of the bonding strap (8)
the bolt (1)
the nut (7)
the bolts (5) and the bolts (6).

5. Close-up
Subtask 28-25-42-410-051-A ** ON A/C NOT FOR ALL

A. Close Access
(1) Install the pipe assembly (Ref. AMM TASK 28-00-00-400-001).
(2) Make sure that the work area is clean and clear of tools and other items.
(3) Install the applicable access panels 540JB 640JB, 540KB 640KB (Ref. AMM TASK 28-10-00-910-002), (Ref. AMM TASK 57-27-11-400-002).

Subtask 28-25-42-410-051-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) Install the applicable access panel 540HB 640HB (Ref. AMM TASK 28-10-00-910-002), (Ref. AMM TASK 57-27-11-400-002).

Subtask 28-25-42-865-052-A

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/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

Subtask 28-25-42-650-053-A

C. 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 28-25-42-942-050-A

D. Removal of Equipment
(1) Remove the safety barriers.
(2) Remove the WARNING NOTICE(S).
(3) Remove the access platform(s).
(4) 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