Installation of the Sequence Valve
TASK 28-21-45-400-003-A
Installation of the Sequence Valve
Self explanatory
2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment
B. Consumable Materials
C. Work Zones and Access Panels
D. Expendable Parts
E. Referenced Information
3. Job Set-up
Subtask 28-21-45-941-053-A ** ON A/C NOT FOR ALL
Subtask 28-21-45-420-058-A ** ON A/C NOT FOR ALL
Subtask 28-21-45-865-057-A ** ON A/C NOT FOR ALL
[Rev.10 from 2021]
2026.04.02 06:17:26 UTC
Installation of the Sequence Valve
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 JobSelf explanatory
2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment
| REFERENCE | QTY | DESIGNATION |
|---|---|---|
| No specific | AR | ACCESS PLATFORM 3M (10 FT) |
| No specific | AR | SAFETY BARRIER(S) |
| No specific | AR | SAFETY CLIP - CIRCUIT BREAKER |
| 99A28404000000 | 1 | ADAPTOR-SEQUENCE VALVE |
| REFERENCE | DESIGNATION |
|---|---|
| (Material No.01ABA1) | Turbine Fuel-- Kerosene - |
| (Material No.03FAB1) | Mineral Oil base Grease-- Vaseline or Petrolatum - |
| (Material No.06ABB1) | Polysulfide Sealant-Fuel Tank Fillet - |
| (Material No.08BAA9) | Non Aqueous Cleaner-General - - |
| (Material No.14SBA1) | Textile-Lint free Cotton - |
| ZONE/ACCESS | ZONE DESCRIPTION |
|---|---|
| 540AB, 540BZ, 640AB, 640BZ |
| FIG.ITEM | DESIGNATION | IPC-CSN |
|---|---|---|
| 1 | O-RING | AIPC 28-21-05-31-030 |
| 2 | O-RING | AIPC 28-21-45-01-040 |
| 6 | O-RING | AIPC 28-21-45-01-070 |
| REFERENCE | DESIGNATION |
|---|---|
| TASK 12-11-28-650-003-A | Pressure Refuel with Automatic Control |
| 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 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 28-21-15-000-003-A | Removal of the Fuel-Pump Pressure-Switch |
| TASK 28-21-15-400-001-A | Installation of the Fuel-Pump Pressure-Switch |
| 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 57-27-11-000-001-A | Removal of the Access Panel |
| TASK 57-27-11-400-001-A | Installation of the Access Panel |
Subtask 28-21-45-941-053-A ** ON A/C NOT FOR ALL
A. Safety Precautions
(2) Make sure that the SAFETY BARRIER(S) are in position.
Subtask 28-21-45-865-055-A ** ON A/C NOT FOR ALL 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) are in position.
B. Make sure that this(these) circuit breaker(s) is(are) open, safetied and tagged:
Subtask 28-21-45-860-052-A ** ON A/C NOT FOR ALL | PANEL | DESIGNATION | FIN | LOCATION |
|---|---|---|---|
| ** ON A/C NOT FOR ALL | |||
| 121VU | FUEL/L WING TK/PUMP2 SPLY | 7QA | N26 |
| 121VU | FUEL/L WING TK/PUMP1 SPLY | 1QA | N23 |
| 121VU | FUEL/R WING TK/PUMP2 SPLY | 8QA | Q26 |
| 121VU | FUEL/R WING TK/PUMP1 SPLY | 2QA | Q23 |
| 123VU | L WING TK/PUMP 1/STBY SPLY | 11QA | AD12 |
| 123VU | R WING TK/PUMP 1/STBY SPLY | 12QA | AE12 |
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 3M (10 FT) is below the applicable access door 540AB(640AB).
(4) Make sure that the applicable access panel is removed 540AB(640AB) (Ref. AMM TASK 28-10-00-910-002), (Ref. AMM TASK 57-27-11-000-001).
(5) Make sure that the applicable surge door 540BZ(640BZ) is held open with the 98D57004014000 HOOK-COVER (RIB2-SURGE DOORS).
4. Procedure(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 3M (10 FT) is below the applicable access door 540AB(640AB).
(4) Make sure that the applicable access panel is removed 540AB(640AB) (Ref. AMM TASK 28-10-00-910-002), (Ref. AMM TASK 57-27-11-000-001).
(5) Make sure that the applicable surge door 540BZ(640BZ) is held open with the 98D57004014000 HOOK-COVER (RIB2-SURGE DOORS).
Subtask 28-21-45-420-058-A ** ON A/C NOT FOR ALL
A. Preparation for Installation
(1) Clean the component interfaces and the adjacent areas with a Textile-Lint free Cotton - (Material No.14SBA1) made moist with Non Aqueous Cleaner-General - - (Material No.08BAA9) .
(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 O-rings (1), (2) and (6) with Turbine Fuel-- Kerosene - (Material No.01ABA1) or Mineral Oil base Grease-- Vaseline or Petrolatum - (Material No.03FAB1) .
Subtask 28-21-45-420-054-A ** ON A/C NOT FOR ALL (1) Clean the component interfaces and the adjacent areas with a Textile-Lint free Cotton - (Material No.14SBA1) made moist with Non Aqueous Cleaner-General - - (Material No.08BAA9) .
(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 O-rings (1), (2) and (6) with Turbine Fuel-- Kerosene - (Material No.01ABA1) or Mineral Oil base Grease-- Vaseline or Petrolatum - (Material No.03FAB1) .
B. Installation of the Sequence Valve
(1) Install the new AIPC 28-21-45-01-070 O-RING (6) between the sequence valve (7) and the elbow (5).
(2) Attach the sequence valve (7) to the elbow (5) with the bolts (4).
(3) Install the new AIPC 28-21-45-01-040 O-RING (2) between the elbow (5) and the mounting plate (9).
(4) Attach the mounting plate (9) to the elbow (5) with the bolts (3).
(5) Install the new AIPC 28-21-05-31-030 O-RING (1) between the sequence valve assembly and the pump canister.
(6) Attach the sequence valve assembly to the pump canister with the bolts (8).
(7) Apply a layer of Polysulfide Sealant-Fuel Tank Fillet - (Material No.06ABB1) to the heads of the bolts (3), (4) and (8).
Subtask 28-21-45-410-051-A ** ON A/C NOT FOR ALL (1) Install the new AIPC 28-21-45-01-070 O-RING (6) between the sequence valve (7) and the elbow (5).
(2) Attach the sequence valve (7) to the elbow (5) with the bolts (4).
(3) Install the new AIPC 28-21-45-01-040 O-RING (2) between the elbow (5) and the mounting plate (9).
(4) Attach the mounting plate (9) to the elbow (5) with the bolts (3).
(5) Install the new AIPC 28-21-05-31-030 O-RING (1) between the sequence valve assembly and the pump canister.
(6) Attach the sequence valve assembly to the pump canister with the bolts (8).
(7) Apply a layer of Polysulfide Sealant-Fuel Tank Fillet - (Material No.06ABB1) to the heads of the bolts (3), (4) and (8).
C. Close Access
(1) Make sure that the work area is clean and clear of tools and other items.
(2) Remove the 98D57004014000 HOOK-COVER (RIB2-SURGE DOORS) and carefully close the applicable surge door 540BZ 640BZ.
(3) Install the applicable access panel 540AB 640AB (Ref. AMM TASK 57-27-11-400-001).
Subtask 28-21-45-860-050-A ** ON A/C NOT FOR ALL (1) Make sure that the work area is clean and clear of tools and other items.
(2) Remove the 98D57004014000 HOOK-COVER (RIB2-SURGE DOORS) and carefully close the applicable surge door 540BZ 640BZ.
(3) Install the applicable access panel 540AB 640AB (Ref. AMM TASK 57-27-11-400-001).
D. Preparation for Test
(1) Remove the applicable pressure switch (Ref. AMM TASK 28-21-15-000-003):
(3) Energize the aircraft electrical circuits (Ref. AMM TASK 24-41-00-861-002).
Subtask 28-21-45-865-056-A ** ON A/C NOT FOR ALL (1) Remove the applicable pressure switch (Ref. AMM TASK 28-21-15-000-003):
- for the sequence valve on the canister 1QM, remove the pressure switch 23QA
- for the sequence valve on the canister 2QM, remove the pressure switch 27QA
- for the sequence valve on the canister 3QM, remove the pressure switch 24QA
- for the sequence valve on the canister 4QM, remove the pressure switch 28QA.
(3) Energize the aircraft electrical circuits (Ref. AMM TASK 24-41-00-861-002).
E. Remove the safety clip(s) and the tag(s) and close this(these) circuit breaker(s):
Subtask 28-21-45-650-053-A ** ON A/C NOT FOR ALL | PANEL | DESIGNATION | FIN | LOCATION |
|---|---|---|---|
| ** ON A/C NOT FOR ALL | |||
| 121VU | FUEL/L WING TK/PUMP2 SPLY | 7QA | N26 |
| 121VU | FUEL/L WING TK/PUMP1 SPLY | 1QA | N23 |
| 121VU | FUEL/R WING TK/PUMP2 SPLY | 8QA | Q26 |
| 121VU | FUEL/R WING TK/PUMP1 SPLY | 2QA | Q23 |
F. Aircraft Maintenance Configuration
(1) Refuel the applicable wing tank to approximately 750 kg (1653.4665 lb) (Ref. AMM TASK 12-11-28-650-003).
Subtask 28-21-45-720-050-A ** ON A/C NOT FOR ALL (1) Refuel the applicable wing tank to approximately 750 kg (1653.4665 lb) (Ref. AMM TASK 12-11-28-650-003).
G. Test of the Sequence Valve
(1) Do this test:
5. Close-up(1) Do this test:
| ACTION | RESULT |
|---|---|
| 1.On the panel 40VU: | |
|
|
| 2.On the pressure gage: |
|
| 3.On the panel 40VU: | |
|
|
Subtask 28-21-45-865-057-A ** ON A/C NOT FOR ALL
A. Open, safety and tag this(these) circuit breaker(s):
Subtask 28-21-45-860-051-A ** ON A/C NOT FOR ALL | PANEL | DESIGNATION | FIN | LOCATION |
|---|---|---|---|
| ** ON A/C NOT FOR ALL | |||
| 121VU | FUEL/L WING TK/PUMP2 SPLY | 7QA | N26 |
| 121VU | FUEL/L WING TK/PUMP1 SPLY | 1QA | N23 |
| 121VU | FUEL/R WING TK/PUMP2 SPLY | 8QA | Q26 |
| 121VU | FUEL/R WING TK/PUMP1 SPLY | 2QA | Q23 |
| 123VU | L WING TK/PUMP 1/STBY SPLY | 11QA | AD12 |
| 123VU | R WING TK/PUMP 1/STBY SPLY | 12QA | AE12 |
B. Aircraft Maintenance Configuration
(1) De-energize the aircraft electrical circuits (Ref. AMM TASK 24-41-00-862-002).
(2) Remove the 99A28404000000 ADAPTOR-SEQUENCE VALVE.
(3) Install the applicable pressure switch (Ref. AMM TASK 28-21-15-400-001).
(4) Make sure that the work area is clean and clear of tools and other items.
Subtask 28-21-45-865-058-A ** ON A/C NOT FOR ALL (1) De-energize the aircraft electrical circuits (Ref. AMM TASK 24-41-00-862-002).
(2) Remove the 99A28404000000 ADAPTOR-SEQUENCE VALVE.
(3) Install the applicable pressure switch (Ref. AMM TASK 28-21-15-400-001).
(4) Make sure that the work area is clean and clear of tools and other items.
C. Remove the safety clip(s) and the tag(s) and close this(these) circuit breaker(s):
Subtask 28-21-45-942-051-A ** ON A/C NOT FOR ALL | PANEL | DESIGNATION | FIN | LOCATION |
|---|---|---|---|
| ** ON A/C NOT FOR ALL | |||
| 121VU | FUEL/L WING TK/PUMP2 SPLY | 7QA | N26 |
| 121VU | FUEL/L WING TK/PUMP1 SPLY | 1QA | N23 |
| 121VU | FUEL/R WING TK/PUMP2 SPLY | 8QA | Q26 |
| 121VU | FUEL/R WING TK/PUMP1 SPLY | 2QA | Q23 |
| 123VU | L WING TK/PUMP 1/STBY SPLY | 11QA | AD12 |
| 123VU | R WING TK/PUMP 1/STBY SPLY | 12QA | AE12 |
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.
(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.
Sequence Valves - Wing-Fuel-Tank Inner-Cell