Removal of the Oxygen Pressure Regulator/Transmitters

TASK 35-13-15-000-802-A
Removal of the Oxygen Pressure Regulator/Transmitters

WARNING: DO NOT FILL OR REPLACE A CREW OXYGEN CYLINDER OR REPLACE A VALVE ASSEMBLY ON THE CREW OXYGEN SYSTEM WHEN YOU FUEL OR DEFUEL THE AIRCRAFT. KEEP ALL HYDROCARBONS (FUELS, LUBRICANTS, ETC.) AWAY FROM ALL SOURCES OF OXYGEN. OXYGEN BECOMES EXPLOSIVE WHEN IT TOUCHES HYDROCARBONS.

WARNING: CLEAN THE TOOLS AND MAKE SURE YOUR HANDS ARE CLEAN TO PREVENT CONTAMINATION OF THE OXYGEN SYSTEM.

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.

CAUTION: PUT DRY AND CLEAN METAL OR PLASTIC PLUGS ON ALL PIPES OR UNITS THAT YOU REMOVE TEMPORARILY. THEN PUT EACH PIPE OR UNIT IN A SEALED VINYL BAG. IF YOU DO NOT OBEY THESE INSTRUCTIONS, CONTAMINATION OF THE OXYGEN SYSTEM CAN OCCUR.

ZONE: 123
ZONE: 210
FIN: 4HT ** ON A/C NOT FOR ALL
FIN: 4HT2 ** 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)
No specific	AR	SAFETY CLIP - CIRCUIT BREAKER
No specific	AR	WARNING NOTICE(S)
FOR [5750HM1] (OXYGEN CYLINDER)
No specific	AR	BAG - VINYL
No specific	AR	BAG - VINYL, SEALED
No specific	AR	CAP - BLANKING
No specific	AR	PLUG - BLANKING, APPROVED FOR USE WITH OXYGEN
FOR [5750HM2] (OXYGEN CYLINDER)
No specific	AR	BAG - VINYL
No specific	AR	BAG - VINYL, SEALED
No specific	AR	CAP - BLANKING
No specific	AR	PLUG - BLANKING, APPROVED FOR USE WITH OXYGEN

B. Work Zones and Access Panels

ZONE/ACCESS	ZONE DESCRIPTION
123	NOSE GEAR WELL
210	CKPT,FWD COMPT BHD TO FLT COMPT BULKHEAD
812

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 35-00-00-860-001-A	Special Precautions When Working on a Gaseous Oxygen System
TASK 35-10-00-870-801-A	Depressurization of the Crew Oxygen System (Manual Shutoff Valve(s) of the Crew Oxygen-Storage Cylinder(s) is (are) Closed)
TASK 52-41-00-010-002-A	Open the Avionics Compartment Doors for Access
Oxygen Pressure Regulator/Transmitters

3. Job Set-up
Subtask 35-13-15-860-060-A ** ON A/C NOT FOR ALL

A. Aircraft Maintenance Configuration

WARNING: WHEN YOU DO WORK ON THE GASEOUS OXYGEN SYSTEM, MAKE SURE THAT YOU OBEY ALL THE APPLICABLE SAFETY PRECAUTIONS. IF YOU DO NOT OBEY THESE PRECAUTIONS, INJURY TO PERSONS AND/OR DAMAGE TO THE AIRCRAFT CAN OCCUR.

(1) Obey the special precautions when you do work on a gaseous oxygen system (Ref. AMM TASK 35-00-00-860-001).
(2) Energize the aircraft electrical circuits
(Ref. AMM TASK 24-41-00-861-002).

Subtask 35-13-15-010-052-A ** ON A/C NOT FOR ALL

B. Get Access
(1) Put the ACCESS PLATFORM 2M (6 FT) in position at access door 812.
(2) Open access door 812 (Ref. AMM TASK 52-41-00-010-002).
(3) Get access to the avionics compartment.

Subtask 35-13-15-860-056-A ** ON A/C NOT FOR ALL

C. Aircraft Maintenance Configuration
(1) Fully close the manual shutoff valves of the crew oxygen-storage cylinders (5750HM1 and 5750HM2).
(2) Put a WARNING NOTICE(S) in position to tell persons not to open the manual shutoff valves of the crew oxygen-storage cylinders (5750HM1 and 5750HM2).

Subtask 35-13-15-614-052-A ** ON A/C NOT FOR ALL

D. Bleeding of the Crew Oxygen System
(1) Release the pressure from the crew oxygen system (Ref. AMM TASK 35-10-00-870-801).
(2) In the cockpit, on the OXYGEN section of overhead control and indicating panel 21VU:

Put a WARNING NOTICE(S) in position to tell persons not to push the CREW SUPPLY pushbutton switch.

Subtask 35-13-15-865-055-A ** ON A/C NOT FOR ALL

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

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C NOT FOR ALL
49VU	OXYGEN/CREW/OXY/SPLY	1HT	HA01

4. Procedure
Subtask 35-13-15-020-052-B ** ON A/C NOT FOR ALL

A. Removal of the Oxygen Pressure Regulator/Transmitters 4HT and 4HT2

CAUTION: USE A SECOND WRENCH TO APPLY COUNTERTORQUE TO THE UNION WHEN YOU DISCONNECT/CONNECT EQUIPMENT FROM FLEXIBLE HOSES AND RIGID TUBING. IF YOU DO NOT USE THE SECOND WRENCH, THERE IS A RISK THAT YOU WILL CAUSE DAMAGE TO THE HOSES AND TUBES.

(1) FOR [5750HM1] (OXYGEN CYLINDER)
(a) Disconnect the electrical connector (4HTA) (9) from the oxygen pressure regulator/transmitter (4HT) (10).
(b) Put a CAP - BLANKING on the electrical connector (4HTA) (9).
(c) Disconnect the HP oxygen-replenishing hose (5767HM1) (1) and discard the ring (2).
(d) Put a PLUG - BLANKING, APPROVED FOR USE WITH OXYGEN on the HP oxygen-replenishing hose (5767HM1) (1).
(e) Put a BAG - VINYL on the disconnected end of the HP oxygen-replenishing hose (5767HM1) (1).
(f) Disconnect the LP oxygen-supply hose (5763HM1) (7) and discard the ring (8).
(g) Put a PLUG - BLANKING, APPROVED FOR USE WITH OXYGEN on the LP oxygen-supply hose (5763HM1) (7).
(h) Put a BAG - VINYL on the disconnected end of the LP oxygen-supply hose (5763HM1) (7).
(i) Disconnect the HP oxygen-overpressure hose (5762HM1) (6) and discard the ring (5).
(j) Put a PLUG - BLANKING, APPROVED FOR USE WITH OXYGEN on the HP oxygen-overpressure hose (5762HM1) (6).
(k) Put a BAG - VINYL on the disconnected end of the HP oxygen-overpressure hose (5762HM1) (6).
(l) Loosen the nut (3) and remove the oxygen pressure regulator/transmitter (4HT) (10) from the oxygen supply outlet (4).
(m) Put the oxygen pressure regulator/transmitter (4HT) (10) in a BAG - VINYL, SEALED.
(n) Put the stowage cap on the oxygen supply outlet (4).

NOTE: The stowage cap of the oxygen supply outlet (4) is in the bag attached to the valve assy of the crew oxygen-storage cylinder (5750HM1).

(2) FOR [5750HM2] (OXYGEN CYLINDER)
(a) Disconnect the electrical connector (4HT2A) (19) from the oxygen pressure regulator/transmitter (4HT2) (20).
(b) Put a CAP - BLANKING on the electrical connector (4HT2A) (19).
(c) Disconnect the HP oxygen-replenishing hose (5767HM2) (11) and discard the ring (12).
(d) Put a PLUG - BLANKING, APPROVED FOR USE WITH OXYGEN on the HP oxygen-replenishing hose (5767HM2) (11).
(e) Put a BAG - VINYL on the disconnected end of the HP oxygen-replenishing hose (5767HM2) (11).
(f) Disconnect the LP oxygen-supply hose (5763HM2) (17) and discard the ring (18).
(g) Put a PLUG - BLANKING, APPROVED FOR USE WITH OXYGEN on the LP oxygen-supply hose (5763HM2) (17).
(h) Put a BAG - VINYL on the disconnected end of the LP oxygen-supply hose (5763HM2) (17).
(i) Disconnect the HP oxygen-overpressure hose (5762HM2) (16) and discard the ring (15).
(j) Put a PLUG - BLANKING, APPROVED FOR USE WITH OXYGEN on the HP oxygen-overpressure hose (5762HM2) (16).
(k) Put a BAG - VINYL on the disconnected end of the HP oxygen-overpressure hose (5762HM2) (16).
(l) Loosen the nut (13) and remove the oxygen pressure regulator/transmitter (4HT2) (20) from the oxygen supply outlet (14).
(m) Put the oxygen pressure regulator/transmitter (4HT2) (20) in a BAG - VINYL, SEALED.
(n) Put the stowage cap on the oxygen supply outlet (14).

NOTE: The stowage cap of the oxygen supply outlet (14) is in the bag attached to the valve assy of the crew oxygen-storage cylinder (5750HM2).

[Rev.10 from 2021] 2026.04.01 12:36:44 UTC