Installation of the AC Service Bus Normal Supply Contactor
TASK 24-51-55-400-001-A
Installation of the AC Service Bus Normal Supply Contactor
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 24-51-55-860-051-A
Subtask 24-51-55-420-050-A ** ON A/C NOT FOR ALL
Subtask 24-51-55-862-050-A Subtask 24-51-55-410-050-A
[Rev.10 from 2021]
2026.03.31 23:24:52 UTC
Installation of the AC Service Bus Normal Supply Contactor
WARNING:
MAKE SURE THAT NO AC OR DC POWER IS CONNECTED TO THE AIRCRAFT ELECTRICAL CIRCUITS.
THERE IS A RISK OF ELECTROCUTION IF THE AC OR DC POWER STAYS CONNECTED.
1. Reason for the JobSelf explanatory
2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment
| REFERENCE | QTY | DESIGNATION |
|---|---|---|
| No specific | 1 | ACCESS PLATFORM 1M (3 FT)-ADJUSTABLE |
| No specific | AR | WARNING NOTICE(S) |
| No specific | Torque wrench: range to between 0.17 and 0.14 m.daN (15.04 and 12.39 lbf.in ) ![]() |
| ZONE/ACCESS | ZONE DESCRIPTION |
|---|---|
| 212 | COCKPIT |
| 121AL |
| REFERENCE | DESIGNATION |
|---|---|
| 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 25-11-41-000-001-A | Removal of the Third Occupant Seat |
| TASK 25-11-41-400-001-A | Installation of the Third Occupant Seat |
Subtask 24-51-55-860-051-A
A. Aircraft Maintenance Configuration
(1) Make sure that the ACCESS PLATFORM 1M (3 FT)-ADJUSTABLE is in position at the access door 121AL.
(2) Make sure that the access door 121AL is open.
(3) Make sure that the external power connector is not connected to the aircraft receptacle.
(4) Make sure that, on the access door 121AL, there is a WARNING NOTICE(S) to tell persons not to connect the external power connector.
(5) In the cockpit, on the overhead ELEC panel 35VU, make sure that these pushbutton switches are released:
(8) In the cockpit, make sure that the third occupant seat is removed (Ref. AMM TASK 25-11-41-000-001).
(9) Make sure that the front panel (8) of the panel 123VU is removed.
Subtask 24-51-55-865-051-A (1) Make sure that the ACCESS PLATFORM 1M (3 FT)-ADJUSTABLE is in position at the access door 121AL.
(2) Make sure that the access door 121AL is open.
(3) Make sure that the external power connector is not connected to the aircraft receptacle.
(4) Make sure that, on the access door 121AL, there is a WARNING NOTICE(S) to tell persons not to connect the external power connector.
(5) In the cockpit, on the overhead ELEC panel 35VU, make sure that these pushbutton switches are released:
- BAT 1, BAT 2,
- APU GEN,
- GEN 1, GEN 2,
- EXT PWR.
- 21VU (EMER ELEC PWR),
- 35VU (ELEC).
(8) In the cockpit, make sure that the third occupant seat is removed (Ref. AMM TASK 25-11-41-000-001).
(9) Make sure that the front panel (8) of the panel 123VU is removed.
B. Make sure that this(these) circuit breaker(s) is(are) open, safetied and tagged:
4. Procedure| PANEL | DESIGNATION | FIN | LOCATION |
|---|---|---|---|
| ** ON A/C ALL | |||
| 122VU | ELEC/AC PWR/SVCE/CTL | 3XX | V29 |
Subtask 24-51-55-420-050-A ** ON A/C NOT FOR ALL
A. Installation of the Contactor
(1) Install the contactor (3) on the 6 tapped barrels (5) of the contactor base (6).
(2) TORQUE the six captive screws (2) to between 0.17 and 0.14 m.daN (15.04 and 12.39 lbf.in )
.
(3) Remove the blanking caps from the electrical connectors (1) and (7).
(4) Make sure that all the electrical connections are clean and in the correct condition.
(5) Connect the electrical connector (1).
Subtask 24-51-55-420-050-B ** ON A/C NOT FOR ALL (1) Install the contactor (3) on the 6 tapped barrels (5) of the contactor base (6).
(2) TORQUE the six captive screws (2) to between 0.17 and 0.14 m.daN (15.04 and 12.39 lbf.in )
. (3) Remove the blanking caps from the electrical connectors (1) and (7).
(4) Make sure that all the electrical connections are clean and in the correct condition.
(5) Connect the electrical connector (1).
A. Installation of the Contactor
(1) Install the contactor (3) on the module 20XX (6).
(2) TORQUE the six captive screws (2) to between 0.17 and 0.14 m.daN (15.04 and 12.39 lbf.in )
.
(3) Remove the blanking caps from the electrical connector (1) and the electrical receptacle (7).
(4) Make sure that all the electrical connections are clean and in the correct condition.
(5) Connect the electrical connector (1) to the contactor (3).
Subtask 24-51-55-865-052-A (1) Install the contactor (3) on the module 20XX (6).
(2) TORQUE the six captive screws (2) to between 0.17 and 0.14 m.daN (15.04 and 12.39 lbf.in )
. (3) Remove the blanking caps from the electrical connector (1) and the electrical receptacle (7).
(4) Make sure that all the electrical connections are clean and in the correct condition.
(5) Connect the electrical connector (1) to the contactor (3).
B. Remove the safety clip(s) and the tag(s) and close this(these) circuit breaker(s):
Subtask 24-51-55-710-050-A | PANEL | DESIGNATION | FIN | LOCATION |
|---|---|---|---|
| ** ON A/C ALL | |||
| 122VU | ELEC/AC PWR/SVCE/CTL | 3XX | V29 |
C. Test of Lights in the Cockpit
(1) Energize the aircraft electrical circuits
(Ref. AMM TASK 24-41-00-861-002).
(2) On the FWD ATTENDANT panel 120RH, push the MAIN ON pushbutton switch.
Make sure that these lights come on:
5. Close-up(1) Energize the aircraft electrical circuits
(Ref. AMM TASK 24-41-00-861-002).
(2) On the FWD ATTENDANT panel 120RH, push the MAIN ON pushbutton switch.
Make sure that these lights come on:
- CEILING FWD RH,
- CEILING AFT RH,
- WINDOW FWD LH,
- WINDOW AFT LH.
Subtask 24-51-55-862-050-A Subtask 24-51-55-410-050-A
B. Close Access
(1) Make sure that the work area is clean and clear of tools and other items.
(2) Install the front panel (8) of the panel 123VU.
(3) Install the Third Occupant seat (Ref. AMM TASK 25-11-41-400-001).
(4) Remove the WARNING NOTICE(S).
(5) Close the access door 121AL.
(6) Remove the access platform(s).
(1) Make sure that the work area is clean and clear of tools and other items.
(2) Install the front panel (8) of the panel 123VU.
(3) Install the Third Occupant seat (Ref. AMM TASK 25-11-41-400-001).
(4) Remove the WARNING NOTICE(S).
(5) Close the access door 121AL.
(6) Remove the access platform(s).
Contactor