Installation of the Additional Center-Tank (ACT) Relay-Box

TASK 25-71-11-400-001-A
Installation of the Additional Center-Tank (ACT) Relay-Box

ZONE: 122
FIN: 802VU ** 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	AR	ACCESS PLATFORM 2M (6 FT) - ADJUSTABLE

B. Work Zones and Access Panels

ZONE/ACCESS	ZONE DESCRIPTION
122	AVIONICS COMPARTMENT
822

C. 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)
Additional Center Tank (ACT) Relay Box

3. Job Set-up
Subtask 25-71-11-860-050-A ** ON A/C NOT FOR ALL

A. Aircraft Maintenance Configuration
(1) Make sure that the aircraft is energized (Ref. AMM TASK 24-41-00-861-002).
(2) Make sure that the ACCESS PLATFORM 2M (6 FT) - ADJUSTABLE is in position at the access door 822.
(3) Make sure that the access door 822 is open.

Subtask 25-71-11-865-052-A ** ON A/C NOT FOR ALL

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
121VU	ACT1/REFUEL & SPLY	33QU	L29
121VU	ACT XFR VALVE MAN CTL	30QH	N29
121VU	ACT1/CTL & SPLY	9QH	P29
** ON A/C NOT FOR ALL
121VU	ACT2/REFUEL & SPLY	34QU	L28
121VU	ACT2/CTL & SPLY	10QH	P28

4. Procedure
Subtask 25-71-11-420-050-A ** ON A/C NOT FOR ALL

A. Installation of the ACT Relay Box
(1) Install the mounting assy (8) and the four screws (9).
(2) Tighten the screws (9).
(3) Install the four clip nuts (7) on the mounting assy (8).
(4) Put the relay box (1) in position on the mounting assy (8).
(5) Install and tighten the four screws (6).
(6) Connect the electrical connectors (4) and (5) to the relay box (1).

NOTE: Make sure that the two electrical connectors are installed correctly.

(7) Install the cover (2) and the four screws (3).
(8) Tighten the screws (3).

5. Close-up
Subtask 25-71-11-865-053-A ** ON A/C NOT FOR ALL

A. 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
121VU	ACT1/REFUEL & SPLY	33QU	L29
121VU	ACT XFR VALVE MAN CTL	30QH	N29
121VU	ACT1/CTL & SPLY	9QH	P29
** ON A/C NOT FOR ALL
121VU	ACT2/REFUEL & SPLY	34QU	L28
121VU	ACT2/CTL & SPLY	10QH	P28

Subtask 25-71-11-410-050-A ** ON A/C NOT FOR ALL

B. Close Access
(1) Close the access door 822.
(2) Remove the access platform(s).

Subtask 25-71-11-862-050-A ** ON A/C NOT FOR ALL

C. De-energize the aircraft electrical circuits
(Ref. AMM TASK 24-41-00-862-002).

[Rev.10 from 2021] 2026.03.31 23:41:55 UTC