Cold Weather Conditions - Put the Oxygen System back into Service

TASK 12-31-35-660-803-A
Cold Weather Conditions - Put the Oxygen System back into Service

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.

WARNING: BE CAREFUL WHEN YOU USE CONSUMABLE MATERIALS. OBEY THE MATERIAL MANUFACTURER'S INSTRUCTIONS AND YOUR LOCAL REGULATIONS.

1. Reason for the Job
Self explanatory
2. Job Set-up Information
A. Consumable Materials

REFERENCE	DESIGNATION
(Material No.14CCB6)	Testing Medium-Leak Detection - Oxygen System
(Material No.14SBA1)	Textile-Lint free Cotton -

B. Referenced Information

REFERENCE	DESIGNATION
TASK 12-33-21-618-001-A	Pre-conditioning through the LP Ground Connection (Aircraft Electrical Power Available)
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 12-33-21-618-001-A-03	Pre-conditioning through the LP Ground Connection (Aircraft Electrical Power Not Available)
TASK 35-00-00-860-001-A	Special Precautions When Working on a Gaseous Oxygen System
TASK 35-12-00-710-001-A	Functional Check of Low Pressure Switch
TASK 35-32-42-400-001-A	Installation of the Portable Oxygen Cylinder

3. Job Set-up
Subtask 12-31-35-941-052-A

A. Not Applicable

4. Procedure
Subtask 12-31-35-420-050-A

A. If removed, install the portable oxygen cylinder-assemblies (Ref. AMM TASK 35-32-42-400-001).

Subtask 12-31-35-660-058-A

B. Prepare the Opening of the Manual Shutoff Valve(s) of the Crew Oxygen-Storage Cylinder(s) when the Outside Air Temperature (OAT) is Less than or Equal to -15 deg.C (5.00 deg.F).
(1) Obey the special precautions when you do work on a gaseous oxygen system (Ref. AMM TASK 35-00-00-860-001).

Subtask 12-31-35-865-056-A

C. Remove the safety clip(s) and the tag(s) and close this(these) circuit breaker(s):

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C ALL
49VU	OXYGEN/CREW/OXY/SPLY	1HT	HA01

Subtask 12-31-35-660-059-A ** ON A/C NOT FOR ALL

D. Procedure to Open the Manual Shutoff Valve(s) of the Crew Oxygen-Storage Cylinder(s) when the Outside Air Temperature (OAT) is Less than or Equal to -15 deg.C (5.00 deg.F).
(1) Do not put the oxygen system back to service if the temperature in the oxygen cylinder compartment is less than or equal to -15 deg.C (5.00 deg.F).
(a) If the temperature in the oxygen cylinder compartment is less than or equal to -15 deg.C (5.00 deg.F), do the pre-conditioning of the aircraft on the ground (Ref. AMM TASK 12-33-21-618-001) and wait for the times that follow:
1 If the OAT is between -55 deg.C (-67.00 deg.F) and -40 deg.C (-40.00 deg.F), wait a minimum time of two hours after the air temperature in the oxygen cylinder compartment is more than or equal to -15 deg.C (5.00 deg.F).
2 If the OAT is between -40 deg.C (-40.00 deg.F) and -15 deg.C (5.00 deg.F), wait a minimum time of one hour after the air temperature in the oxygen cylinder compartment is more than or equal to -15 deg.C (5.00 deg.F).
(2) Do a leak test:
(a) Apply the oxygen leak detector Testing Medium-Leak Detection - Oxygen System (Material No.14CCB6) to the mechanical connections.
(b) Slowly and fully open in one step the manual shutoff valve of the crew oxygen-storage cylinder (5750HM).
(c) Examine each connection to make sure that there are no leaks.
(d) Remove the oxygen leak detector Testing Medium-Leak Detection - Oxygen System (Material No.14CCB6) from the mechanical connections with a lint-free cotton cloth Textile-Lint free Cotton - (Material No.14SBA1) .
(3) Do the operational test of the crew oxygen distribution (Ref. AMM TASK 35-12-00-710-001).
(4) Make sure that the work area is clean and clear of tools and other items.
(5) Remove the WARNING NOTICE(S).

Subtask 12-31-35-660-059-B ** ON A/C NOT FOR ALL

D. Procedure to Open the Manual Shutoff Valves of the Crew Oxygen-Storage Cylinders when the Outside Air Temperature (OAT) is Less than or Equal to -15 deg.C (5.00 deg.F).
(1) Do not put the oxygen system back to service if the temperature in the oxygen cylinder compartment is less than or equal to -15 deg.C (5.00 deg.F).
(a) If the temperature in the oxygen cylinder compartment is less than or equal to -15 deg.C (5.00 deg.F), do the pre-conditioning of the aircraft on the ground (Ref. AMM TASK 12-33-21-618-001) and wait for the times that follow:
1 If the OAT is between -55 deg.C (-67.00 deg.F) and -40 deg.C (-40.00 deg.F), wait a minimum time of two hours after the air temperature in the oxygen cylinder compartment is more than or equal to -15 deg.C (5.00 deg.F).
2 If the OAT is between -40 deg.C (-40.00 deg.F) and -15 deg.C (5.00 deg.F), wait a minimum time of one hour after the air temperature in the oxygen cylinder compartment is more than or equal to -15 deg.C (5.00 deg.F).
(2) Do a leak test:
(a) Apply the oxygen leak detector Testing Medium-Leak Detection - Oxygen System (Material No.14CCB6) to the mechanical connections.
(b) On the manual shutoff valves of the two crew-oxygen-storage cylinders (5750HM1) and (5750HM2):

Remove the WARNING NOTICE(S).

(c) Slowly and fully open in one step the manual shutoff valves of the two crew-oxygen-storage cylinders (5750HM1) and (5750HM2).
(d) Examine each connection to make sure that there are no leaks.
(e) Remove the oxygen leak detector Testing Medium-Leak Detection - Oxygen System (Material No.14CCB6) from the mechanical connections with a lint-free cotton cloth Textile-Lint free Cotton - (Material No.14SBA1) .
(3) Do the operational test of the crew oxygen distribution (Ref. AMM TASK 35-12-00-710-001).
(4) Make sure that the work area is clean and clear of tools and other items.
(5) In the cockpit, on the OXYGEN section of the overhead control and indicating panel 21VU:

Remove the WARNING NOTICE(S).

[Rev.10 from 2021] 2026.04.02 06:10:34 UTC