Installation of the Pressure Regulating Valve - Aft Cargo-Compartment Heating

TASK 21-43-52-400-001-A
Installation of the Pressure Regulating Valve - Aft Cargo-Compartment Heating

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.

FIN: 11HC ** 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 2M (6 FT)
No specific	1	WARNING NOTICE(S)

B. Work Zones and Access Panels

ZONE/ACCESS	ZONE DESCRIPTION
197BB
197KB

C. Expendable Parts

FIG.ITEM	DESIGNATION	IPC-CSN
25	O-RINGS	AIPC 21-43-04-14-070
25	O-RINGS	AIPC 21-43-84-16-030

D. Referenced Information

REFERENCE	DESIGNATION
TASK 12-33-21-618-001-A-01	Pre-conditioning through the HP Ground Connection
TASK 12-33-21-618-001-A-02	Pre-conditioning with the APU
TASK 20-28-00-912-802-A	Electrical Bonding - General Maintenance Procedure
TASK 20-28-00-912-803-A	Bonding Surface Preparation
TASK 21-43-00-710-003-A	Operational Test of the AFT Cargo Compartment Heating System
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 53-35-13-000-002-A	Removal of the Quick-Release Access Panels from the Belly Fairing Structure
TASK 53-35-13-400-002-A	Installation of the Quick-Release Access Panels on the Belly Fairing Structure
Pressure Regulating Valve - Component Location ** ON A/C NOT FOR ALL
Pressure Regulating Valve - Component Location ** ON A/C NOT FOR ALL
Pressure Regulating Valve - Component Location ** ON A/C NOT FOR ALL

3. Job Set-up
Subtask 21-43-52-860-050-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 WARNING NOTICE(S) is (are) in position in the cockpit to tell persons not to start the APU.
(3) In the cockpit, on AIR COND panel 30VU, make sure that:

The APU BLEED pushbutton switch is released (the OFF legend is on).
The ENG 1 BLEED and the ENG 2 BLEED pushbutton switches are released (the OFF legends are on).

(a) The WARNING NOTICE(S) is (are) in position to tell persons not to operate these pushbutton switches.
(4) On the HP ground connector, make sure that the WARNING NOTICE(S) is (are) in position to tell persons not to supply the ground air.
(5) Make sure that the ACCESS PLATFORM 2M (6 FT) is in position at access panel 197BB.
(6) Make sure that access panel 197BB is removed (Ref. AMM TASK 53-35-13-000-002).

Subtask 21-43-52-860-050-C ** ON A/C NOT FOR ALL

The APU BLEED pushbutton switch is released (the OFF legend is on).
The ENG 1 BLEED and the ENG 2 BLEED pushbutton switches are released (the OFF legends are on).

(a) The WARNING NOTICE(S) is (are) in position to tell persons not to operate these pushbutton switches.
(4) On the HP ground connector, make sure that the WARNING NOTICE(S) is (are) in position to tell persons not to supply the ground air.
(5) Make sure that the ACCESS PLATFORM 2M (6 FT) is in position at access panel 197KB.
(6) Make sure that access panel 197KB is removed (Ref. AMM TASK 53-35-13-000-002).

Subtask 21-43-52-865-061-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
49VU	AIR COND/AFT CARGO/VENT/CTL & MONG	31HN	C07
** ON A/C NOT FOR ALL
49VU	AIR COND/AFT CARGO/VENT & HTG/CTL & MONG	31HN	C07
** ON A/C NOT FOR ALL
121VU	APU/APU/CTL	2KD	L42
121VU	APU/ECB/SPLY	1KD	L41
121VU	APU/FIRE/EXTIG/SQUIB/B	2WF	L39
121VU	APU/FIRE/EXTIG/SQUIB/A	1WF	L38
122VU	AIR COND/AFT CARGO VENT/FAN	30HN	S22

4. Procedure
Subtask 21-43-52-420-050-A ** ON A/C NOT FOR ALL

A. Installation of the Pressure Regulating Valve
(1) Unlock and turn the manual override and the position indicator (14) to the open position.
(2) Remove the protective covers from the pressure regulating valve (30), the pipe assembly (27) and the ducts (24) and (32).
(3) Make sure that the parts retained from the removed component are clean and in the correct condition.
(4) Clean the component interfaces and the adjacent area.
(5) Prepare the surface of the bonding point(s)
(Ref. AMM TASK 20-28-00-912-803).
(6) Make sure that the O-rings (25) are in good condition.
(7) If necessary, replace the AIPC 21-43-04-14-070 O-RINGS (25).
(8) Put the O-ring (25) in position on the pipe assembly (27).
(9) Put the pressure regulating valve (30) in position on the pipe assembly (27) and install the clamp (28):
(a) Make sure that the arrow on the body of the pressure regulating valve points in the direction of the airflow.
(b) Do not fully tighten the clamp (28) at this time.
(10) Put the O-rings (25) in position on the flange of the duct (32) and the pressure regulating valve (30).
(11) Put the pressure regulating valve (30) and the pipe assembly (27) in position on the ducts (24) and (32) and install the clamps (26) and (33):
(a) Do not fully tighten the clamps (26) and (33) at this time.
(12) Make sure that the pipe assembly (27) is in its correct installation position.
(13) Put the tie-rods (1) and (5) in position and install the bolts (2), the washers (3) and the nuts (4).
(14) Make sure that the pressure regulating valve (30) is in its correct installation position.

NOTE: When you look in the forward direction, the manual override and the position indicator (14) are at the 5 o'clock position.

(15) Remove the PLUG-BLANKING from each disconnected line end.
(16) Connect the sense line (29).
(17) Tighten the clamps (26), (28) and (33).
(18) Put the bonding strap (7) in position on the pressure regulating valve (30) and install the screw (6), the washer (8) and the nut (9).
(19) Put the bonding straps (7) and (12) in position and install the screw (13), the washer (11) and the nut (10).
(20) Do the electrical resistance measurement and the final protection of the bonding point(s)
(Ref. AMM TASK 20-28-00-912-802).
(21) Remove the CAP-BLANKING from each electrical connector and receptacle.

CAUTION: MAKE SURE THAT THE BONDING STRAP(S) IS(ARE) CONNECTED BEFORE YOU CONNECT THE ELECTRICAL CONNECTOR(S).

CAUTION: MAKE SURE THAT THE ELECTRICAL CONNECTORS ARE CLEAN BEFORE YOU DISCONNECT OR CONNECT THEM. CONTAMINATION ON THE ELECTRICAL CONNECTORS CAN CAUSE DAMAGE TO EQUIPMENT.

(22) Connect the electrical connector (31).
(23) Make sure that the work area is clean and clear of tools and other items.

Subtask 21-43-52-420-050-C ** ON A/C NOT FOR ALL

A. Installation of the Pressure Regulating Valve
(1) Unlock and turn the manual override and the position indicator (14) to the open position.
(2) Remove the protective covers from the pressure regulating valve (30), the pipe assembly (27) and the ducts (24) and (32).
(3) Make sure that the parts retained from the removed component are clean and in the correct condition.
(4) Clean the component interfaces and the adjacent area.
(5) Prepare the surface of the bonding point(s)
(Ref. AMM TASK 20-28-00-912-803).
(6) Make sure that the O-rings (25) are in good condition.
(7) If necessary, replace the AIPC 21-43-04-14-070 O-RINGS (25) or AIPC 21-43-84-16-030 O-RINGS (25).
(8) Put the O-ring (25) in position on the pipe assembly (27).
(9) Put the pressure regulating valve (30) in position on the pipe assembly (27) and install the clamp (28):
(a) Make sure that the arrow on the body of the pressure regulating valve points in the direction of the airflow.
(b) Do not fully tighten the clamp (28) at this time.
(10) Put the O-rings (25) in position on the flange of the duct (32) and the pressure regulating valve (30).
(11) Put the pressure regulating valve (30) and the pipe assembly (27) in position on the ducts (24) and (32) and install the clamps (26) and (33):
(a) Do not fully tighten the clamps (26) and (33) at this time.
(12) Make sure that the pipe assembly (27) is in its correct installation position.
(13) Put the tie-rods (1) and (5) in position and install the bolts (2), the washers (3) and the nuts (4).
(14) Make sure that the pressure regulating valve (30) is in its correct installation position.

NOTE: When you look in the forward direction, the manual override and the position indicator (14) are at the 2 o'clock position at an angle of 52 degrees.

CAUTION: MAKE SURE THAT THE BONDING STRAP(S) IS(ARE) CONNECTED BEFORE YOU CONNECT THE ELECTRICAL CONNECTOR(S).

CAUTION: MAKE SURE THAT THE ELECTRICAL CONNECTORS ARE CLEAN BEFORE YOU DISCONNECT OR CONNECT THEM. CONTAMINATION ON THE ELECTRICAL CONNECTORS CAN CAUSE DAMAGE TO EQUIPMENT.

(22) Connect the electrical connector (31).
(23) Make sure that the work area is clean and clear of tools and other items.

Subtask 21-43-52-865-062-A ** ON A/C NOT FOR ALL

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	AIR COND/AFT CARGO/VENT/CTL & MONG	31HN	C07
** ON A/C NOT FOR ALL
49VU	AIR COND/AFT CARGO/VENT & HTG/CTL & MONG	31HN	C07
** ON A/C NOT FOR ALL
121VU	APU/APU/CTL	2KD	L42
121VU	APU/ECB/SPLY	1KD	L41
121VU	APU/FIRE/EXTIG/SQUIB/B	2WF	L39
121VU	APU/FIRE/EXTIG/SQUIB/A	1WF	L38
122VU	AIR COND/AFT CARGO VENT/FAN	30HN	S22

Subtask 21-43-52-710-050-A ** ON A/C NOT FOR ALL

C. Test
(1) Do the pre-conditioning through the HP ground connector (Ref. AMM TASK 12-33-21-618-001) or with the APU (Ref. AMM TASK 12-33-21-618-001).
(2) Do a leak check of the pressure regulating valve and sense line connections.

NOTE: Leaks are not permitted.

(3) After approx. 15 minutes stop the pre-conditioning (Ref. AMM TASK 12-33-21-618-001) or (Ref. AMM TASK 12-33-21-618-001).
(4) Do the operational test of the AFT cargo-compartment heating system (Ref. AMM TASK 21-43-00-710-003).

5. Close-up
Subtask 21-43-52-410-050-A ** ON A/C NOT FOR ALL

A. Close Access
(1) Make sure that the work area is clean and clear of tools and other items.
(2) Install the access panel 197BB (Ref. AMM TASK 53-35-13-400-002).
(3) Remove the access platform(s).
(4) Remove the WARNING NOTICE(S).

Subtask 21-43-52-410-050-C ** ON A/C NOT FOR ALL

A. Close Access
(1) Make sure that the work area is clean and clear of tools and other items.
(2) Install the access panel 197KB (Ref. AMM TASK 53-35-13-400-002).
(3) Remove the access platform(s).
(4) Remove the WARNING NOTICE(S).

Subtask 21-43-52-862-050-A ** ON A/C NOT FOR ALL

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

[Rev.10 from 2021] 2026.04.01 04:53:11 UTC