Installation of the Drain Mast

TASK 28-13-43-400-001-A
Installation of the Drain Mast

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: OBEY THE FUEL SAFETY PROCEDURES.

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	SCRAPER - NON METALLIC
No specific	Torque wrench: range to between 2.0 and 1.8 m.daN (14.75 and 13.27 lbf.ft )

B. Consumable Materials

REFERENCE	DESIGNATION
(Material No.03KBB1)	Fluorosilicone base Grease-System Fuel and oil resistant -
(Material No.04QAB2)	Coating_- Flexible Structure
(Material No.06AAB1)	Polysulfide Sealant-General Purpose Fillet -
(Material No.06AAC1)	Polysulfide Sealant-General Purpose Interfay -
(Material No.06AEA1)	Polysulfide Sealant-Low Adhesion Brushable -
(Material No.08BAA9)	Non Aqueous Cleaner-General - -

C. Work Zones and Access Panels

ZONE/ACCESS	ZONE DESCRIPTION
148FB

D. Expendable Parts

FIG.ITEM	DESIGNATION	IPC-CSN
3	O-RING	AIPC 28-13-03-04-200
3	O-RING	AIPC 28-13-83-04-230
6	O-RING	AIPC 28-22-03-01-080
6	O-RING	AIPC 28-22-83-01-090

E. Referenced Information

REFERENCE	DESIGNATION
TASK 20-28-00-912-802-A	Electrical Bonding - General Maintenance Procedure
TASK 28-00-00-910-001-A	Fuel Safety Procedures
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
Drain Mast

3. Job Set-up
Subtask 28-13-43-869-050-A

A. Aircraft Maintenance Configuration
(1) Obey the fuel safety procedures (Ref. AMM TASK 28-00-00-910-001).
(2) Make sure that the access panel 148FB is open (Ref. AMM TASK 53-35-13-000-001).

4. Procedure
Subtask 28-13-43-560-050-A

A. Preparation for the Replacement Component
(1) Remove the straight union (7) from the drain mast (5) and discard the O-ring (6).
(2) Remove the sealant with a SCRAPER - NON METALLIC from the mount base of the drain mast and from the fuselage.
(3) Clean the mount base of the drain mast and the fuselage with Non Aqueous Cleaner-General - - (Material No.08BAA9) .
(4) Make sure that the straight union (7) is in a clean and correct condition.
(5) Apply a thin layer of Fluorosilicone base Grease-System Fuel and oil resistant - (Material No.03KBB1) to the new AIPC 28-22-03-01-080 O-RING (6) or AIPC 28-22-83-01-090 O-RING (6).
(6) Install the O-ring (6) on the straight union (7).
(7) Install the straight union (7) with Polysulfide Sealant-Low Adhesion Brushable - (Material No.06AEA1) on the drain mast (5).
(8) Torque the straight union (7) to between 2.0 and 1.8 m.daN (14.75 and 13.27 lbf.ft )

.
(9) Apply Coating_- Flexible Structure (Material No.04QAB2) to the installed and torqued straight union (7).

Subtask 28-13-43-420-051-A

B. Installation of the Drain Mast
(1) Preparation for installation
(a) Remove the blanking plugs from the disconnected line ends.
(b) Apply a thin layer of the Fluorosilicone base Grease-System Fuel and oil resistant - (Material No.03KBB1) to the new AIPC 28-13-03-04-200 O-RING (3) or AIPC 28-13-83-04-230 O-RING (3).
(c) Put the new O-ring (3) on the end of the center tank vent-pipe (2).
(d) Apply the Fluorosilicone base Grease-System Fuel and oil resistant - (Material No.03KBB1) to the end of the center tank vent-pipe (2).
(e) Apply the Polysulfide Sealant-General Purpose Interfay - (Material No.06AAC1) to the mount base of the drain mast (5).
(f) Make sure that the drain mast outlets are not blocked.
(2) Install the drain mast (5)
(a) Carefully push the end of the center tank vent-pipe (2) into the drain mast (5).
(b) Install the drain mast (5) to the fuselage and tighten the four countersunk screws (4).
(c) Prepare for electrical bonding:

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.

1 Make sure that the screws (4) are correctly bonded (Ref. AMM TASK 20-28-00-912-802).
(d) Seal the end of the center tank vent-pipe (2) with Fluorosilicone base Grease-System Fuel and oil resistant - (Material No.03KBB1) .
(e) Connect the APU vent-pipe (1) to the straight union (7). Torque the nut (8) to between 2.0 and 1.8 m.daN (14.75 and 13.27 lbf.ft )

.
(f) Apply a thin bead of the Polysulfide Sealant-General Purpose Fillet - (Material No.06AAB1) to the drain mast.
(g) Make sure that the drain mast outlets are not blocked.

5. Close-up
Subtask 28-13-43-410-050-A

A. Close Access
(1) Make sure that the work area is clean and clear of tools and other items.
(2) Remove the ground support and maintenance equipment, the special and standard tools and all other items.
(3) Install access panel 148FB on the right side of the belly fairing (Ref. AMM TASK 53-35-13-400-001).

[Rev.10 from 2021] 2026.04.02 07:02:11 UTC