Installation of the Fwd Cargo Compartment Isolation Valve

TASK 21-28-51-400-001-A
Installation of the Fwd Cargo Compartment Isolation Valve

WARNING: MAKE SURE THAT AIR IS NOT SUPPLIED TO THE AIR CONDITIONING SYSTEM FROM THE MAIN ENGINE, THE APU OR A GROUND SOURCE. HOT COMPRESSED AIR CAN CAUSE INJURY TO PERSONNEL.

CAUTION: BE VERY CAREFUL WHEN YOU DO WORK ON OR NEAR THE AIR-CONDITIONING DUCTS. THE DUCTS ARE MADE OF THIN MATERIAL AND YOU CAN EASILY BREAK THEM.

ZONE: 131
ZONE: 132
FIN: 4HN ** ON A/C NOT FOR ALL
FIN: 5HN ** 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 3M (10 FT)- ADJUSTABLE
No specific	AR	WARNING NOTICE(S)

B. Work Zones and Access Panels

ZONE/ACCESS	ZONE DESCRIPTION
131	FORWARD CARGO COMPARTMENT
132	FORWARD CARGO COMPARTMENT
825
FOR [4HN] (ISOL VALVE FWD CARGO OUTLET)
132KW
FOR [5HN] (ISOL VALVE FWD CARGO INLET)
131QW

C. Referenced Information

REFERENCE	DESIGNATION
TASK 21-28-00-710-004-A	Operational Test of the FWD Cargo-Compartment Outlet Isolation-Valve in the Ditching Configuration
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 25-54-12-000-003-A	Removal of the Sidewall Panels in the Forward Cargo Compartment
TASK 25-54-12-400-003-A	Installation of the Sidewall Panels in the Forward Cargo Compartment
TASK 52-30-00-860-001-A	Open the FWD or Aft Cargo-Compartment Door with the Yellow Electric Pump
TASK 52-30-00-860-002-A	Close the FWD or Aft Cargo-Compartment Door with the Yellow Electric Pump
Isolation Valve
Isolation Valve

3. Job Set-up
Subtask 21-28-51-860-050-A ** ON A/C NOT FOR ALL

A. Aircraft Maintenance Configuration
(1) Make sure that the aircraft electrical circuits are energized.
(Ref. AMM TASK 24-41-00-861-002).
(2) Make sure that the ACCESS PLATFORM 3M (10 FT)- ADJUSTABLE is in position below the forward cargo compartment.

Subtask 21-28-51-941-052-A ** ON A/C NOT FOR ALL

B. Safety Precautions
(1) In the cockpit, on the overhead panel, on the AIR COND section of panel 30VU:
(a) Make sure that:
1 The APU BLEED pushbutton switch is in the off position (the ON legend is off).
2 The ENG 1 BLEED and the ENG 2 BLEED pushbutton switches are in the off position (the OFF legends are on).
3 The PACK 1 and PACK 2 pushbutton switches are released (the OFF legends are on).
(b) Make sure that the WARNING NOTICE(S) are in position to tell persons not to operate these pushbutton switches.
(2) On the HP and the LP ground connectors:
(a) Make sure that the WARNING NOTICE(S) is in position to tell persons not to supply the ground air.

Subtask 21-28-51-010-051-B ** ON A/C NOT FOR ALL

C. Get Access
(1) Make sure that forward cargo-compartment door 825 is open (Ref. AMM TASK 52-30-00-860-001).
(2) Make sure that the sidewall panels are removed (Ref. AMM TASK 25-54-12-000-003):
(a) FOR [4HN] (ISOL VALVE FWD CARGO OUTLET)
132KW.
(b) FOR [5HN] (ISOL VALVE FWD CARGO INLET)
131QW.

Subtask 21-28-51-865-054-A ** ON A/C NOT FOR ALL

D. 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	AIR COND/FWD CARGO/VENT/CTL & MONG	2HN	C08
122VU	FWD CARGO VENT AND HTG/FAN	1HN	T22

Subtask 21-28-51-210-050-A ** ON A/C NOT FOR ALL

E. Make sure that the clamps, the sleeve and the valve are in the correct condition. Replace them if necessary.

Subtask 21-28-51-160-050-A ** ON A/C NOT FOR ALL

F. Clean the component interfaces and the adjacent area.

4. Procedure
Subtask 21-28-51-420-050-A ** ON A/C NOT FOR ALL

A. Installation of the Valve
(1) Remove the blanking plugs:
(a) For FIN 5HN from the ducts (1) and (9).
(b) For FIN 4HN from the duct (1) and the fan (9).
(2) Install the sleeve (7):
(a) For FIN 5HN on the duct (9).
(b) For FIN 4HN on the fan (9).
(3) Install the valve (4) in the sleeve (7):
(a) For FIN 5HN the arrow which shows the airflow direction must point forward.
(b) For FIN 4HN the arrow which shows the airflow direction must point rearward.
(4) Put the centering lug (1) in position in the valve housing and install the valve (4).
(5) Install the clamp (2) and TORQUE to the value given on the clamp (2).
(6) Put the sleeve (7) in position.
(7) Install the clamps (6) and (8) and tighten them.
(8) Remove the blanking cap from the electrical connector (5) and make sure that the electrical connector is clean and in the correct condition.
(9) Connect the electrical connector (5).
(10) Connect the bonding strip (3).

Subtask 21-28-51-942-050-A ** ON A/C NOT FOR ALL

B. Make sure that the work area is clean and clear of tools and other items.

Subtask 21-28-51-865-055-A ** ON A/C NOT FOR ALL

C. 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	AIR COND/FWD CARGO/VENT/CTL & MONG	2HN	C08
122VU	FWD CARGO VENT AND HTG/FAN	1HN	T22

Subtask 21-28-51-710-050-A ** ON A/C NOT FOR ALL

D. Do an operational test of the FWD cargo compartment ventilation (Ref. AMM TASK 21-28-00-710-004).

5. Close-up
Subtask 21-28-51-410-050-B ** ON A/C NOT FOR ALL

A. Close Access
(1) Install the sidewall panels (Ref. AMM TASK 25-54-12-400-003):
(a) FOR [4HN] (ISOL VALVE FWD CARGO OUTLET)
132KW.
(b) FOR [5HN] (ISOL VALVE FWD CARGO INLET)
131QW.
(2) Close forward cargo-compartment door 825 (Ref. AMM TASK 52-30-00-860-002).
(3) Remove the access platform(s).
(4) Remove the WARNING NOTICE(S).

Subtask 21-28-51-862-050-A ** ON A/C NOT FOR ALL

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

[Rev.10 from 2021] 2026.04.02 06:11:11 UTC