Installation of the Standby Compass Bulb

TASK 34-22-23-400-002-A
Installation of the Standby Compass Bulb

ZONE: 210

1. Reason for the Job
Self explanatory
2. Job Set-up Information
A. Work Zones and Access Panels

ZONE/ACCESS	ZONE DESCRIPTION
210	CKPT,FWD COMPT BHD TO FLT COMPT BULKHEAD

B. Referenced Information

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 34-22-00-710-001-A	Operational Check of the Standby Compass Including Light Test and Visual Check
TASK 34-22-00-710-001-A-01	Operational Check of the Standby Compass Including Light Test and Visual Check (with the Standby Compass Calibrator)
Standby Compass Bulb

3. Job Set-up
Subtask 34-22-23-861-051-A

A. Aircraft Maintenance Configuration
(1) Make sure that the aircraft electrical circuits are energized
(Ref. AMM TASK 24-41-00-861-002).

Subtask 34-22-23-865-057-A

B. Make sure that this(these) circuit breaker(s) is(are) open, safetied and tagged:

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C NOT FOR ALL
49VU	LIGHTING/STBY/COMP/LIGHT	1LF	H04
** ON A/C NOT FOR ALL
49VU	LIGHTING/STBY/COMP/LIGHT	1LF	H02

4. Procedure
Subtask 34-22-23-420-051-B

A. Installation of the Standby Compass Bulb
(1) Clean the component interfaces and the adjacent area.
(2) Do an inspection of the component interfaces and the adjacent area.
(3) Make sure that the parts retained from the removed component are clean and in the correct condition.
(4) On overhead panel 25VU, on the INT LT section, make sure that STBY COMPASS switch 2LF is in the OFF position.
(5) On the windshield center post, on the standby compass (3):
(a) Put the bulb (2) in position on the coil spring of the standby compass (3).

NOTE: We recommend that you install a non-magnetized bulb in the standby compass.

(b) Put the lamp cap (1) in position on the standby compass (3).
(c) Turn the lamp cap (1) clockwise to tighten it.

Subtask 34-22-23-865-058-A

B. Remove the safety clip(s) and the tag(s) and close this(these) circuit breaker(s):

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C NOT FOR ALL
49VU	LIGHTING/STBY/COMP/LIGHT	1LF	H04
** ON A/C NOT FOR ALL
49VU	LIGHTING/STBY/COMP/LIGHT	1LF	H02

Subtask 34-22-23-710-051-A

C. Test(s)
(1) Do the operational test of the standby compass light (Ref. AMM TASK 34-22-00-710-001).

5. Close-up
Subtask 34-22-23-860-054-A

A. Put the aircraft back to its initial configuration.
(1) Remove all the fixtures, tools, test and support equipment used during this procedure.
(2) Make sure that the work area is clean and clear of tools and other items.
(3) De-energize the aircraft electrical circuits
(Ref. AMM TASK 24-41-00-862-002).

[Rev.10 from 2021] 2026.04.02 06:23:14 UTC