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

TASK 21-43-52-000-001-A
Removal 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	AR	CAP - BLANKING
No specific	AR	PLUG - BLANKING
No specific	AR	SAFETY CLIP - CIRCUIT BREAKER
No specific	1	WARNING NOTICE(S)

B. Work Zones and Access Panels

ZONE/ACCESS	ZONE DESCRIPTION
197BB
197KB

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 53-35-13-000-002-A	Removal of the Quick-Release Access Panels from 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 21-43-52-861-050-A ** ON A/C NOT FOR ALL

A. Energize the aircraft electrical circuits (Ref. AMM TASK 24-41-00-861-002).

Subtask 21-43-52-865-060-A ** ON A/C NOT FOR ALL

B. Open, safety and tag 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 21-43-52-941-050-A ** ON A/C NOT FOR ALL

C. Safety Precautions
(1) Put the WARNING NOTICE(S) in the cockpit to tell persons not to start the APU.
(2) 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) Put the WARNING NOTICE(S) in position to tell persons not to operate these switches.
(3) On the HP ground connector, put the WARNING NOTICE(S) in position to tell persons not to supply the ground air.

Subtask 21-43-52-010-050-A ** ON A/C NOT FOR ALL

D. Get Access
(1) Put the ACCESS PLATFORM 2M (6 FT) in position at the access panel 197BB.
(2) Remove the access panel 197BB (Ref. AMM TASK 53-35-13-000-002).

Subtask 21-43-52-010-050-C ** ON A/C NOT FOR ALL

D. Get Access
(1) Put the ACCESS PLATFORM 2M (6 FT) in position at the access panel 197KB.
(2) Remove the access panel 197KB (Ref. AMM TASK 53-35-13-000-002).

4. Procedure
Subtask 21-43-52-020-051-A ** ON A/C NOT FOR ALL

A. Removal of the Pressure Regulating Valve
(1) Disconnect the electrical connector (31).
(2) Put the CAP-BLANKING on each disconnected electrical connector and receptacle.
(3) Disconnect the sense line (29).
(4) Put the PLUG-BLANKING in each disconnected line end.
(5) Remove the nut (10), the washer (11), the screw (13) and disconnect the bonding straps (7) and (12).
(6) Remove the nuts (4), the washers (3), the bolts (2) and disconnect the tie-rods (1) and (5).
(7) Remove the nut (9), the washer (8), the screw (6) and remove and retain the bonding strap (7).
(8) Hold the pressure regulating valve (30) together with the pipe assembly (27) and remove the clamps (26) and (33).
(9) Remove the regulating valve (30) and the pipe assembly (27) from the aircraft.
(10) Remove the O-rings (25).
(11) Remove the clamp (28) and move apart the pressure regulating valve (30) and the pipe assembly (27).
(12) Remove the O-ring (25).
(13) Put protective covers on the open ends of the ducts (24) and (32), the pipe assembly (27) and the regulating valve (30).
(14) On the pressure regulating valve (30) move and lock the manual override and position indicator (14) in the closed position.

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