Functional Check of Tank Vapor Seal and Vent Drain System (Aircraft Fitted with a Center Tank)

TASK 28-18-00-700-001-A
Functional Check of Tank Vapor Seal and Vent Drain System (Aircraft Fitted with a Center Tank)

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

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: 137
ZONE: 138
ZONE: 148

1. Reason for the Job
Refer to the MPD TASK: 281800-01
FUNCTIONAL CHECK OF TANK VAPOUR SEAL AND VENT DRAIN SYSTEM (SFAR88)
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	GAGE 300 MM (12 IN) - PRESSURE, U-TUBE
No specific	1	LOCALLY MANUFACTURED - ADAPTER
No specific	1	REGULATOR - PRESSURE
No specific	AR	SAFETY BARRIER(S)
No specific	AR	WARNING NOTICE(S)
98D28108647000	1	DEVICE-CHECK,VAPOR SEAL

B. Consumable Materials

REFERENCE	DESIGNATION
(Material No.14CBB1)	Testing Medium-Leak Detection Bubbles -
(Material No.14CCB6)	Testing Medium-Leak Detection - Oxygen System
(Material No.14QFB1)	Wire-Locking Dia: 0.8 mm CRES Nickel Alloy -

C. Work Zones and Access Panels

ZONE/ACCESS	ZONE DESCRIPTION
137	BAY BETW AFT PART. BULKHEAD OF FWD CARGO
138	BAY BETW AFT PART. BULKHEAD OF FWD CARGO
148	MAIN GEAR WELL AND HYDRAULIC COMPARTMENT
132PW
131NW, 825
241AF

D. 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 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 53-32-12-000-002-A	Removal of the Cabin Floor Panels
TASK 53-32-12-400-002-A	Installation of the Cabin Floor Panels
TASK 28-13-42-300-001-A	Center-Tank Vapor-Seal-Membrane Repair (for corrective action)
Center Tank External Vent System ** ON A/C NOT FOR ALL
Center Tank External Vent System ** ON A/C NOT FOR ALL
Center Tank External Vent System ** ON A/C NOT FOR ALL
Center-Tank External Vent-System ** ON A/C NOT FOR ALL

3. Job Set-up
Subtask 28-18-00-941-050-A

WARNING: OBEY THE FUEL SAFETY PROCEDURES.

A. Safety Precautions

Center Tank External Vent System ** ON A/C NOT FOR ALL

Center-Tank External Vent-System ** ON A/C NOT FOR ALL

(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) As necessary, use the applicable SAFETY BARRIERS, specified by the operator's instructions and your local regulations.
(3) Put the WARNING NOTICE(S) on the applicable panels that follow, to tell persons not to operate refuel/defuel system:

Refuel/defuel control-panels 801VU and 800VU
Fuel control-panel 40VU
Additional Center Tank (ACT) fuel control-panel 28VU.

Subtask 28-18-00-010-050-A ** ON A/C NOT FOR ALL

B. Get Access

NOTE: Do one of the two procedures that follow.

(1) Get access:
(a) Put the ACCESS PLATFORM 2M (6 FT) in position below the applicable access panel.
(b) Open the forward cargo-compartment door 825 (Ref. AMM TASK 52-30-00-860-001).
(c) Remove the access panel 131NW.
(2) Get access:
(a) Remove the floor panel 241AF (Ref. AMM TASK 53-32-12-000-002).

Subtask 28-18-00-010-050-C ** ON A/C NOT FOR ALL

B. Get Access
(1) Put the ACCESS PLATFORM 2M (6 FT) in position below the applicable access panel.
(2) Open the forward cargo-compartment door 825 (Ref. AMM TASK 52-30-00-860-001).
(3) Remove the access panels 131NW and 132PW.

Subtask 28-18-00-010-050-F ** ON A/C NOT FOR ALL

B. Get Access
(1) Remove floor panel 231BMG (Ref. AMM TASK 53-22-12-000-001).

Subtask 28-18-00-020-050-A ** ON A/C NOT FOR ALL

C. Preparation for Check

WARNING: MAKE SURE THAT THE TEST EQUIPMENT HAS A SAFETY SYSTEM TO PREVENT ACCIDENTAL PRESSURE INCREASE.

(1) If necessary, remove the check valve (3) as follows:

WARNING: USE PROTECTIVE GOGGLES AND GLOVES WHEN YOU REMOVE OR INSTALL LOCKWIRE. EACH TIME YOU CUT LOCKWIRE, REMOVE AND DISCARD IT IMMEDIATELY. LOOSE LOCKWIRE CAN CUT YOU OR MAKE YOU BLIND, AND/OR CAN CAUSE DAMAGE.

(a) Remove and discard the lockwire from the three bolts (1).
(b) Remove the three bolts (1) and the washers (2).
(c) Remove the check valve (3).
(2) Do one of the two steps that follow:
(a) If you use the 98D28108647000 DEVICE-CHECK,VAPOR SEAL test kit, do the steps that follow:
1 Connect the ADAPTOR-CHECK VALVE to the check valve housing (4).
2 Connect the ground air supply capable of 0.1 bar (1.4504 psi) to REGULATOR-PRESSURE.
3 Connect the REGULATOR-PRESSURE to the ADAPTOR-CHECK VALVE on the check valve housing (4).
(b) If you use the LOCALLY MANUFACTURED - ADAPTER, do the steps that follow:
1 Connect the LOCALLY MANUFACTURED - ADAPTER to the check valve housing (4).
2 Connect the ground air supply capable of 0.1 bar (1.4504 psi) to the REGULATOR - PRESSURE.
3 Connect the REGULATOR - PRESSURE to the LOCALLY MANUFACTURED - ADAPTER on the check valve housing (4).
(3) Set the ground air supply to a pressure of 0.1 bar (1.4504 psi) ( 1020 mm (40.1575 in.) of water).

Subtask 28-18-00-020-050-B ** ON A/C NOT FOR ALL

C. Preparation for Check

WARNING: MAKE SURE THAT THE TEST EQUIPMENT HAS A SAFETY SYSTEM TO PREVENT ACCIDENTAL PRESSURE INCREASE.

(1) Do one of the two steps that follow:
(a) If you use the 98D28108647000 DEVICE-CHECK,VAPOR SEAL test kit, do the steps that follow:
1 Connect the ADAPTOR-CHECK VALVE to the check-valve extension hose.
2 Connect the ground air supply capable of 0.1 bar (1.4504 psi) to REGULATOR-PRESSURE.
3 Connect the REGULATOR-PRESSURE to the ADAPTOR-CHECK VALVE on the check-valve extension hose.
(b) If you use the LOCALLY MANUFACTURED - ADAPTER, do the steps that follow:
1 Connect the LOCALLY MANUFACTURED - ADAPTER to the check-valve extension hose.
2 Connect the ground air supply capable of 0.1 bar (1.4504 psi) to the REGULATOR - PRESSURE.
3 Connect the REGULATOR - PRESSURE to the LOCALLY MANUFACTURED - ADAPTER on the check-valve extension hose.
(2) Set the ground air supply to a pressure of 0.1 bar (1.4504 psi) ( 1020 mm (40.1575 in.) of water).

4. Procedure
Subtask 28-18-00-720-050-A ** ON A/C NOT FOR ALL

A. Functional Check of Tank Vapor Seal and Vent Drain System
(1) Operate the ground air-supply and supply a pressure of 0.1 bar (1.4504 psi) (1020 mm (40.1575 in.) of water) through the vent and drain system.
(2) Make sure that the air flows freely through the check valve housing (4), the system and the drain mast.
(3) Stop the ground air-supply.
(4) Do one of the two steps that follow:
(a) If you use the 98D28108647000 DEVICE-CHECK,VAPOR SEAL test kit, do the steps that follow:
1 Connect the ADAPTOR-DRAIN MAST to the GAGE - PRESSURE, DIGITAL.
2 Install the ADAPTOR-DRAIN MAST on the ventilation pipe outlet of the center-tank drain mast.
(b) If you use the LOCALLY MANUFACTURED - ADAPTER, install the GAGE 300 MM (12 IN) - PRESSURE, U-TUBE on the ventilation pipe outlet of the center-tank drain mast.

CAUTION: MAKE SURE THAT THE VENT AND DRAIN SYSTEM IS NOT PRESSURIZED TO MORE THAN 0.01 BAR (0.1450 PSI). THIS CAN CAUSE DAMAGE TO THE VAPOUR SEAL.

(5) Pressurize the vent and drain system with one of the two steps that follow:
(a) If you use the 98D28108647000 DEVICE-CHECK,VAPOR SEAL test kit, do the steps that follow:
1 Operate the ground air-supply.
2 Slowly turn the REGULATOR-PRESSURE and make sure that the GAGE - PRESSURE, DIGITAL shows the pressure value 0.01 bar (0.1450 psi) (100 mm (3.9370 in.) of water).

NOTE: The GAGE - PRESSURE, DIGITAL shows the pressure value in the vent and drain system.

(b) If you use the LOCALLY MANUFACTURED - ADAPTER, do the steps that follow:
1 Operate the ground air-supply.
2 Slowly turn the REGULATOR - PRESSURE and make sure that the GAGE 300 MM (12 IN) - PRESSURE, U-TUBE shows the pressure value 0.01 bar (0.1450 psi) (100 mm (3.9370 in.) of water).

NOTE: The GAGE 300 MM (12 IN) - PRESSURE, U-TUBE shows the pressure value in the vent and drain system.

(6) Stop the ground air-supply.
(7) Measure the leakage rate. It must not be more than 0.005 bar (0.0725 psi) (50 mm (1.9685 in.) of water) in 30 seconds.
(8) If the leak rate is more than permitted, continue as follows:
(a) Operate the ground air-supply to supply a constant pressure of 0.01 bar (0.1450 psi) (100 mm (3.9370 in.) of water) to the vent and drain system.
(b) Use Testing Medium-Leak Detection Bubbles - (Material No.14CBB1) or Testing Medium-Leak Detection - Oxygen System (Material No.14CCB6) to examine the vapor seal and its interfaces for leaks.
(c) Repair the vapor seal (Ref. AMM TASK 28-13-42-300-001) and/or the pipe connections.
(d) Do the leak test of the center-tank/box external ventilating-system again.
(9) Release the air pressure from the vent and drain system.
(10) Carefully remove the ADAPTOR-DRAIN MAST that is the part of 98D28108647000 DEVICE-CHECK,VAPOR SEAL or the GAGE 300 MM (12 IN) - PRESSURE, U-TUBE from the drain mast.

NOTE: All the pressure in the vent and drain system will be released.

Subtask 28-18-00-720-050-B ** ON A/C NOT FOR ALL

A. Functional Check of Tank Vapor Seal and Vent Drain System
(1) Operate the ground air-supply and supply a pressure of 0.1 bar (1.4504 psi) (1020 mm (40.1575 in.) of water) through the vent and drain system.
(2) Make sure the air flows freely through the check-valve extension hose, the system and the drain mast.
(3) Stop the ground air-supply.
(4) Do one of the two steps that follow:
(a) If you use the 98D28108647000 DEVICE-CHECK,VAPOR SEAL test kit, do the steps that follow:
1 Connect the ADAPTOR-DRAIN MAST to the GAGE - PRESSURE, DIGITAL.
2 Install the ADAPTOR-DRAIN MAST on the ventilation pipe outlet of the center-tank drain mast.
(b) If you use the LOCALLY MANUFACTURED - ADAPTER, install the GAGE 300 MM (12 IN) - PRESSURE, U-TUBE on the ventilation pipe outlet of the center-tank drain mast.

CAUTION: MAKE SURE THAT THE VENT AND DRAIN SYSTEM IS NOT PRESSURIZED TO MORE THAN 0.01 BAR (0.1450 PSI). THIS CAN CAUSE DAMAGE TO THE VAPOUR SEAL.

NOTE: The GAGE - PRESSURE, DIGITAL shows the pressure value in the vent and drain system.

NOTE: The GAGE 300 MM (12 IN) - PRESSURE, U-TUBE shows the pressure value in the vent and drain system.

(6) Stop the ground air-supply.
(7) Measure the leakage rate. It must not be more than 0.005 bar (0.0725 psi) (50 mm (1.9685 in.) of water) in 30 seconds.
(8) If the leak rate is more than permitted, continue as follows:
(a) Operate the ground air-supply to supply a constant pressure of 0.01 bar (0.1450 psi) (100 mm (3.9370 in.) of water) to the vent and drain system.
(b) Use Testing Medium-Leak Detection Bubbles - (Material No.14CBB1) or Testing Medium-Leak Detection - Oxygen System (Material No.14CCB6) to examine the vapor seal and its interfaces for leaks.
(c) Repair the vapor seal (Ref. AMM TASK 28-13-42-300-001) and/or the pipe connections.
(d) Do the leak test of the center-tank/box external ventilating-system again.
(9) Carefully remove the ADAPTOR-DRAIN MAST that is the part of 98D28108647000 DEVICE-CHECK,VAPOR SEAL or the GAGE 300 MM (12 IN) - PRESSURE, U-TUBE from the drain mast.

NOTE: All the pressure in the vent and drain system will be released.

5. Close-up
Subtask 28-18-00-410-050-A ** ON A/C NOT FOR ALL

A. Close Access
(1) Disconnect the ground air-supply connection from the REGULATOR-PRESSURE.
(2) Remove the REGULATOR-PRESSURE and the ADAPTOR-CHECK VALVE or LOCALLY MANUFACTURED - ADAPTER from the check valve housing (4).
(3) If necessary, install the check valve (3) as follows:
(a) Install the check valve (3) in the check valve housing (4).
(b) Install the three bolts (1) and the washers (2).

(c) Safety the bolts (1), as shown, with 14QFB1Wire-Locking Dia: 0.8 mm CRES Nickel Alloy -.
(4) Manually operate the check valve (3) to make sure it opens and closes correctly.
(5) Make sure that the work area is clean and clear of tools and other items.
(6) Make sure that all of the bonding straps are correctly installed and attached (Ref. AMM TASK 20-28-00-912-802), before you install the access panel(s).
(7) If applicable, install the access panel 131NW.
(8) If applicable, install the floor panel 241AF (Ref. AMM TASK 53-32-12-400-002).
(9) If applicable, close the forward cargo-compartment door (Ref. AMM TASK 52-30-00-860-002).

Subtask 28-18-00-410-050-C ** ON A/C NOT FOR ALL

A. Close Access
(1) Disconnect the ground air-supply connection from the REGULATOR-PRESSURE.
(2) Remove the REGULATOR-PRESSURE and the ADAPTOR-CHECK VALVE or LOCALLY MANUFACTURED - ADAPTER from the check-valve extension hose.
(3) Make sure that the work area is clean and clear of tools and other items.
(4) Make sure that all of the bonding straps are correctly installed and attached (Ref. AMM TASK 20-28-00-912-802), before you install the access panel(s).
(5) Install the access panels 131NW and 132PW.
(6) Close the forward cargo-compartment door (Ref. AMM TASK 52-30-00-860-002).

Subtask 28-18-00-410-050-G ** ON A/C NOT FOR ALL

A. Close Access
(1) Disconnect the ground air-supply connection from the REGULATOR-PRESSURE.
(2) Remove the REGULATOR-PRESSURE and the ADAPTOR-CHECK VALVE or LOCALLY MANUFACTURED - ADAPTER from the check valve housing (4).
(3) If necessary, install the check valve (3) as follows:
(a) Install the check valve (3) in the check valve housing (4).
(b) Install the three bolts (1) and the washers (2).

(c) Safety the bolts (1), as shown, with 14QFB1Wire-Locking Dia: 0.8 mm CRES Nickel Alloy -.
(4) Manually operate the check valve (3) to make sure it opens and closes correctly.
(5) Make sure that the work area is clean and clear of tools and other items.
(6) Make sure that all of the bonding straps are correctly installed and attached (Ref. AMM TASK 20-28-00-912-802), before you install the access panel(s).
(7) Install the access panels 131NW and 132PW.
(8) Close the forward cargo-compartment door (Ref. AMM TASK 52-30-00-860-002).

Subtask 28-18-00-410-050-H ** ON A/C NOT FOR ALL

A. Close Access
(1) Disconnect the ground air-supply connection from the REGULATOR - PRESSURE.
(2) Remove the REGULATOR - PRESSURE and the ADAPTOR-CHECK VALVE or LOCALLY MANUFACTURED - ADAPTER from the check valve housing (4).
(3) If necessary, install the check valve (3) as follows:
(a) Install the check valve (3) in the check valve housing (4).
(b) Install the bolts (1) and the washers (2).

(c) Safety the bolts (1) with a 14QFB1Wire-Locking Dia: 0.8 mm CRES Nickel Alloy -.
(4) Manually operate the check valve (3) to make sure it open and closes correctly.
(5) Make sure that the work area is clean and clear of tools and other items.
(6) Make sure that all of the bonding straps are correctly installed and attached (Ref. AMM TASK 20-28-00-912-802), before you install the access panel(s).
(7) Install floor panel 231BMG (Ref. AMM TASK 53-22-12-400-001).

Subtask 28-18-00-942-050-A

B. Removal of Equipment
(1) Remove the safety barriers.
(2) Remove the access platform(s).
(3) Remove the WARNING NOTICE(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 07:02:12 UTC