Removal of the Sequence Valve
TASK 28-21-45-000-001-A
Removal of the Sequence Valve
Self Explanatory
2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment
B. Work Zones and Access Panels
C. Referenced Information
3. Job Set-up
Subtask 28-21-45-941-050-A ** ON A/C NOT FOR ALL
Subtask 28-21-45-020-051-A ** ON A/C NOT FOR ALL
[Rev.10 from 2021]
2026.04.02 06:17:26 UTC
Removal of the Sequence Valve
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.
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.
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 |
| 98D57004014000 | 1 | HOOK-COVER (RIB2-SURGE DOORS) |
| ZONE/ACCESS | ZONE DESCRIPTION |
|---|---|
| 540AB, 540BZ, 640AB, 640BZ |
| REFERENCE | DESIGNATION |
|---|---|
| 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 57-27-11-000-001-A | Removal of the Access Panel |
Subtask 28-21-45-941-050-A ** ON A/C NOT FOR ALL
A. Safety Precautions
(2) Put the SAFETY BARRIER(S) in position.
Subtask 28-21-45-865-050-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) Put the SAFETY BARRIER(S) in position.
B. Open, safety and tag this(these) circuit breaker(s):
Subtask 28-21-45-650-052-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. Fuel Configuration
(1) Defuel the applicable fuel tank (Ref. AMM TASK 28-25-00-650-001).
(2) Drain the remaining fuel from the applicable fuel tank (Ref. AMM TASK 28-25-00-650-003).
Subtask 28-21-45-010-050-A ** ON A/C NOT FOR ALL (1) Defuel the applicable fuel tank (Ref. AMM TASK 28-25-00-650-001).
(2) Drain the remaining fuel from the applicable fuel tank (Ref. AMM TASK 28-25-00-650-003).
D. Get Access
(1) Put the ACCESS PLATFORM 3M (10 FT) in position below the applicable access panel 540AB(640AB).
(2) Remove the applicable access panel 540AB 640AB (Ref. AMM TASK 28-10-00-910-002), (Ref. AMM TASK 57-27-11-000-001).
(3) Open the applicable access door 540BZ 640BZ and install the 98D57004014000 HOOK-COVER (RIB2-SURGE DOORS).
4. Procedure(1) Put the ACCESS PLATFORM 3M (10 FT) in position below the applicable access panel 540AB(640AB).
(2) Remove the applicable access panel 540AB 640AB (Ref. AMM TASK 28-10-00-910-002), (Ref. AMM TASK 57-27-11-000-001).
(3) Open the applicable access door 540BZ 640BZ and install the 98D57004014000 HOOK-COVER (RIB2-SURGE DOORS).
Subtask 28-21-45-020-051-A ** ON A/C NOT FOR ALL
A. Removal of the Sequence Valve
(1) Remove the bolts (8) and then the sequence valve assembly from the pump canister. Remove and discard the O-ring (1).
(2) Remove the bolts (3), move the mounting plate (9) and the elbow (5) apart and discard the O-ring (2).
(3) Remove the bolts (4), move the elbow (5) and the sequence valve (7) apart and discard the O-ring (6).
(1) Remove the bolts (8) and then the sequence valve assembly from the pump canister. Remove and discard the O-ring (1).
(2) Remove the bolts (3), move the mounting plate (9) and the elbow (5) apart and discard the O-ring (2).
(3) Remove the bolts (4), move the elbow (5) and the sequence valve (7) apart and discard the O-ring (6).
NOTE: It is possible to adapt this procedure to remove only part of the assembly.
Sequence Valves - Wing-Fuel-Tank Inner-Cell