Removal of the Ground Power Control Unit (GPCU)

TASK 24-41-34-000-001-A
Removal of the Ground Power Control Unit (GPCU)

CAUTION: MAKE SURE THAT NO AC OR DC POWER IS CONNECTED TO THE AIRCRAFT ELECTRICAL CIRCUITS. THERE IS A RISK OF DAMAGE TO EQUIPMENT DURING ITS REMOVAL/ INSTALLATION IF THE AC OR DC POWER STAYS CONNECTED.

ZONE: 122
FIN: 1XG ** ON A/C NOT FOR ALL

1. Reason for the Job
Self 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	1	ACCESS PLATFORM 2M (6 FT) - ADJUSTABLE
No specific	AR	CAP - BLANKING
No specific	AR	SAFETY CLIP - CIRCUIT BREAKER
No specific	AR	WARNING NOTICE(S)

B. Work Zones and Access Panels

ZONE/ACCESS	ZONE DESCRIPTION
122	AVIONICS COMPARTMENT
121AL, 811

C. Referenced Information

REFERENCE	DESIGNATION
Ground Power Control Unit (GPCU)

3. Job Set-up
Subtask 24-41-34-010-050-A ** ON A/C NOT FOR ALL

A. Get Access
(1) Put an ACCESS PLATFORM 2M (6 FT) - ADJUSTABLE at the access door 811.
(2) Open the access door 811.
(3) Put an ACCESS PLATFORM 1M (3 FT)-ADJUSTABLE at the access door 121AL.
(4) Open the access door 121AL.

Subtask 24-41-34-941-051-A ** ON A/C NOT FOR ALL

B. Safety Precautions
(1) Make sure that the external power connector is not connected to the aircraft receptacle.
(2) Put WARNING NOTICE(S) on the access door 121AL to tell persons not to use the external power receptacle.
(3) In the cockpit, on the overhead ELEC panel 35VU, release these pushbutton switches:

BAT 1, BAT 2,
APU GEN,
GEN 1, GEN 2,
EXT PWR.

(4) In the cockpit, put WARNING NOTICE(S) to tell persons not to operate the pushbutton switches on these overhead panels:

21VU (EMER ELEC PWR),
35VU (ELEC).

(5) In the cockpit, on the APU section of the overhead panel 25VU, put WARNING NOTICE(S) to tell persons not to start the APU.

Subtask 24-41-34-865-056-A ** ON A/C NOT FOR ALL

C. Open, safety and tag this(these) circuit breaker(s):

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C NOT FOR ALL
122VU	ELEC/EXT PWR/CTL	11XG	X29
122VU	ELEC/GPCU	7XG	Y24
123VU	GND/PWR/PROT	2XG	AB07

4. Procedure
Subtask 24-41-34-020-050-A ** ON A/C NOT FOR ALL

A. Removal of the GPCU
(1) Loosen the two knurled nuts (1).
(2) Lower the two knurled nuts (1) to release the two studs (2).
(3) Carefully pull on the handle (3) of the GPCU (4) until the fixed connector (5) is disconnected.
(4) Remove the GPCU from its rack (6).
(5) Put the CAP-BLANKING on each disconnected electrical connector and receptacle.

[Rev.10 from 2021] 2026.03.31 23:24:16 UTC