Replacement of the Overboard Discharge Indicators

TASK 35-13-22-920-802-A
Replacement of the Overboard Discharge Indicators

WARNING: KEEP ALL HYDROCARBONS (FUELS, LUBRICANTS, ETC.) AWAY FROM ALL SOURCE 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.

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: 5756HM1 ** ON A/C NOT FOR ALL
FIN: 5756HM2 ** 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	SAFETY CLIP - CIRCUIT BREAKER
No specific	AR	WARNING NOTICE(S)
FOR [5750HM1] (OXYGEN CYLINDER)
No specific	1	AIR SOURCE 0.3 TO 0.7 BAR (5 TO 10 PSI)- FILTERED, DRY
No specific	AR	BAG - VINYL, SEALED
No specific	AR	CAP - BLANKING, APPROVED FOR USE WITH OXYGEN
No specific	1	PLIERS - CIRCLIP
No specific	AR	PLUG - BLANKING, APPROVED FOR USE WITH OXYGEN
No specific	Torque wrench: range to between 2.7 and 1.9 m.daN (19.91 and 14.01 lbf.ft )
No specific	Torque wrench: range to between 3.95 and 3.05 m.daN (29.13 and 22.49 lbf.ft )
FOR [5750HM2] (OXYGEN CYLINDER)
No specific	1	AIR SOURCE 0.3 TO 0.7 BAR (5 TO 10 PSI)- FILTERED, DRY
No specific	AR	BAG - VINYL, SEALED
No specific	AR	CAP - BLANKING, APPROVED FOR USE WITH OXYGEN
No specific	1	PLIERS - CIRCLIP
No specific	AR	PLUG - BLANKING, APPROVED FOR USE WITH OXYGEN
No specific	Torque wrench: range to between 2.7 and 1.9 m.daN (19.91 and 14.01 lbf.ft )
No specific	Torque wrench: range to between 3.95 and 3.05 m.daN (29.13 and 22.49 lbf.ft )

B. Consumable Materials

REFERENCE	DESIGNATION
FOR [5750HM1] (OXYGEN CYLINDER)
(Material No.14SBA1)	Textile-Lint free Cotton -
FOR [5750HM2] (OXYGEN CYLINDER)
(Material No.14SBA1)	Textile-Lint free Cotton -

C. Work Zones and Access Panels

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

D. Expendable Parts

FIG.ITEM	DESIGNATION	IPC-CSN
FOR [5750HM1] (OXYGEN CYLINDER)
6	RING FOR FLARED TUBE	AIPC 35-12-81-09-010
3	RING FOR FLARED TUBE	AIPC 35-12-81-09-020
11	KIT	AIPC 35-13-22-01-010
FOR [5750HM2] (OXYGEN CYLINDER)
13	RING FOR FLARED TUBE	AIPC 35-12-81-11-010
16	RING FOR FLARED TUBE	AIPC 35-12-81-11-030
22	KIT	AIPC 35-13-22-01-010

E. 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 52-41-00-010-002-A	Open the Avionics Compartment Doors for Access
TASK 52-41-00-410-002-A	Close the Avionics Compartment Doors after Access
Overboard Discharge Indicators
FOR [5750HM1] (OXYGEN CYLINDER)
TASK 20-23-22-910-001-A	Marking of the Unions after Application of Standard or Specific Tightening Torque
FOR [5750HM2] (OXYGEN CYLINDER)
TASK 20-23-22-910-001-A	Marking of the Unions after Application of Standard or Specific Tightening Torque

3. Job Set-up
Subtask 35-13-22-860-051-A ** ON A/C NOT FOR ALL

A. Aircraft Maintenance Configuration
(1) Obey the special precautions when you do work on a gaseous oxygen system (Ref. AMM TASK 35-00-00-860-001).
(2) In the cockpit, on the OXYGEN section of the overhead control and indicating panel 21VU:

Make sure that the CREW SUPPLY pushbutton switch is released (OFF legend on).
Put a WARNING NOTICE(S) in position to tell persons not to operate the oxygen system.

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

Subtask 35-13-22-010-052-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 35-13-22-941-052-A ** ON A/C NOT FOR ALL

C. Aircraft Maintenance Configuration
(1) Fully close the manual shutoff valve of the crew oxygen-storage cylinder 5750HM1.
(2) Fully close the manual shutoff valve of the crew oxygen-storage cylinder 5750HM2.
(3) Put 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 35-13-22-614-050-A ** ON A/C NOT FOR ALL

D. Bleeding of the Two Oxygen Systems
(1) In the cockpit, on the OXYGEN section of the overhead control and indicating panel 21VU, push the CREW SUPPLY pushbutton switch (the OFF legend goes off).
(2) On the Captain oxygen-mask stowage-box, push and hold the PRESS TO TEST AND RESET control button.
At the same time, push and hold the PRESS TO TEST/EMERGENCY knob on the mask regulator.
(a) Keep them pushed for a minimum of three seconds.

NOTE: During this time, the flow rate indicator changes from yellow to black and the volume of the sound of the oxygen flow decreases.

(b) When the flow rate indicator is black and when you no longer hear the sound of the oxygen flow:

Release the PRESS TO TEST/EMERGENCY knob.
Release the PRESS TO TEST AND RESET control button.

WARNING: MAKE SURE THAT THE PRESS TO TEST/EMERGENCY KNOB IS NOT IN THE EMERGENCY POSITION. IF IT IS IN THE EMERGENCY POSITION, THERE CAN BE A LEAK OF OXYGEN.

1 Make sure that the PRESS TO TEST/EMERGENCY knob is not in the EMERGENCY position.
(3) On the First-Officer oxygen-mask stowage-box, push and hold the PRESS TO TEST AND RESET control button.
At the same time, push and hold the PRESS TO TEST/EMERGENCY knob on the mask regulator.
(a) Keep them pushed for a minimum of three seconds.

NOTE: During this time, the flow rate indicator changes from yellow to black and the volume of the sound of the oxygen flow decreases.

(b) When the flow rate indicator is black and when you no longer hear the sound of the oxygen flow:

Release the PRESS TO TEST/EMERGENCY knob.
Release the PRESS TO TEST AND RESET control button.

WARNING: MAKE SURE THAT THE PRESS TO TEST/EMERGENCY KNOB IS NOT IN THE EMERGENCY POSITION. IF IT IS IN THE EMERGENCY POSITION, THERE CAN BE A LEAK OF OXYGEN.

1 Make sure that the PRESS TO TEST/EMERGENCY knob is not in the EMERGENCY position.
(4) In the cockpit, on the OXYGEN section of the overhead control and indicating panel 21VU:

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

Subtask 35-13-22-865-050-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 35-13-22-020-051-A ** ON A/C NOT FOR ALL

A. Replacement of the Overboard Discharge Indicators (5756HM1, 5756HM2)

(1) FOR [5750HM1] (OXYGEN CYLINDER)
(a) Disconnect the LP oxygen-overpressure-hose 5762HM1 from the oxygen pressure-regulator/transmitter 4HT (1) as follows:

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 Release and disconnect the union (4).
2 Discard the ring for flared tube (3).
3 Put an CAP - BLANKING, APPROVED FOR USE WITH OXYGEN on the LP overpressure port (2).
(b) Disconnect the HP oxygen-overpressure-hose 5761HM1 from the valve (5) as follows:

1 Release and disconnect the union (7).
2 Discard the ring for flared tube (6).
3 Put an CAP - BLANKING, APPROVED FOR USE WITH OXYGEN on the HP overpressure outlet (8).
(c) Get access to the overboard-discharge indicator 5756HM1 (10) from the outside of the aircraft.
(d) Remove and discard the replaceable units of the overboard-discharge indicator 5756HM1 (10) as follows:

CAUTION: DO NOT LET UNWANTED PARTICLES GO INTO THE OXYGEN SYSTEM.

1 Remove the retaining ring with PLIERS - CIRCLIP.
2 Remove the reflective green disc.
3 Remove the support of the reflective green disc.
4 Remove the adhesive reflective yellow washer.
(e) Clean the overboard-discharge indicator 5756HM1 (10) with a clean Textile-Lint free Cotton - (Material No.14SBA1) .
(f) Clean the HP oxygen-overpressure-hose 5761HM1 and the LP oxygen-overpressure-hose 5762HM1 with air to remove contamination and unwanted objects as follows:
1 Get a AIR SOURCE 0.3 TO 0.7 BAR (5 TO 10 PSI)- FILTERED, DRY.
2 Blow air two or three times (one hose after the other each time) to make sure that there are no unwanted objects in the system.
3 Put an PLUG - BLANKING, APPROVED FOR USE WITH OXYGEN on the unions (4) and (7).
4 Put a BAG - VINYL, SEALED on the unions (4) and (7).
(g) Install the new replaceable units of the kit on the overboard-discharge indicator 5756HM1 as follows:
1 Get access to the overboard-discharge indicator 5756HM1 (10) from the outside of the aircraft.
2 Make sure that the overboard-discharge indicator 5756HM1 (10) is clean.
3 Get the AIPC 35-13-22-01-010 KIT (11) and install the new units as follows:

Install the adhesive reflective yellow washer into the bottom of the overboard-discharge indicator 5756HM1 (10). Make sure that the yellow side is out.
Attach the reflective green disc on its support and put this assembly on the overboard-discharge indicator 5756HM1 (10). Make sure that the green side is out.
Use PLIERS - CIRCLIP and install the retaining ring with its rounded edges in.

(h) Connect the LP oxygen-overpressure-hose 5762HM1 to the oxygen pressure-regulator/transmitter 4HT (1) as follows:

1 Remove the CAP - BLANKING, APPROVED FOR USE WITH OXYGEN from the LP overpressure port (2).
2 Install a new AIPC 35-12-81-09-020 RING FOR FLARED TUBE (3) on the union (4).
3 Install the union (4) on the LP overpressure port (2).
4 TORQUE the union (4) to between 3.95 and 3.05 m.daN (29.13 and 22.49 lbf.ft )

.
5 Identify the tightened union nuts with a red line (Ref. AMM TASK 20-23-22-910-001).
(i) Connect the HP oxygen-overpressure-hose 5761HM1 to the valve (5):

1 Remove the CAP - BLANKING, APPROVED FOR USE WITH OXYGEN from the HP overpressure outlet (8).
2 Install a new AIPC 35-12-81-09-010 RING FOR FLARED TUBE (6) on the union (7).
3 Install the union (7) on the HP overpressure outlet (8).
4 TORQUE the union (7) to between 2.7 and 1.9 m.daN (19.91 and 14.01 lbf.ft )

.
5 Identify the tightened union nuts with a red line (Ref. AMM TASK 20-23-22-910-001).
(2) FOR [5750HM2] (OXYGEN CYLINDER)
(a) Disconnect the LP oxygen-overpressure-hose 5762HM2 from the oxygen pressure-regulator/transmitter 4HT2 (20) as follows:

1 Release and disconnect the union (14).
2 Discard the ring for flared tube (13).
3 Put an CAP - BLANKING, APPROVED FOR USE WITH OXYGEN on the LP overpressure port (12).
(b) Disconnect the HP oxygen-overpressure-hose 5761HM2 from the valve (15) as follows:

1 Release and disconnect the union (17).
2 Discard the ring for flared tube (16).
3 Put an CAP - BLANKING, APPROVED FOR USE WITH OXYGEN on the HP overpressure outlet (18).
(c) Get access to the overboard-discharge indicator 5756HM2 (21) from the outside of the aircraft.
(d) Remove and discard the replaceable units of the overboard-discharge indicator 5756HM2 (21) as follows:

CAUTION: DO NOT LET UNWANTED PARTICLES GO INTO THE OXYGEN SYSTEM.

1 Remove the retaining ring with PLIERS - CIRCLIP.
2 Remove the reflective green disc.
3 Remove the support of the reflective green disc.
4 Remove the adhesive reflective yellow washer.
(e) Clean the overboard-discharge indicator 5756HM2 (21) with a clean Textile-Lint free Cotton - (Material No.14SBA1) .
(f) Clean the HP oxygen-overpressure-hose 5761HM2 and the LP oxygen-overpressure-hose 5762HM2 with air to remove contamination and unwanted objects as follows:
1 Get a AIR SOURCE 0.3 TO 0.7 BAR (5 TO 10 PSI)- FILTERED, DRY.
2 Blow air two or three times (one hose after the other each time) to make sure that there are no unwanted objects in the system.
3 Put an PLUG - BLANKING, APPROVED FOR USE WITH OXYGEN on the unions (14) and (17).
4 Put a BAG - VINYL, SEALED on the unions (14) and (17).
(g) Install the new replaceable units of the kit on the overboard-discharge indicator 5756HM2 as follows:
1 Get access to the overboard-discharge indicator 5756HM2 (21) from the outside of the aircraft.
2 Make sure that the overboard-discharge indicator 5756HM2 (21) is clean.
3 Get the AIPC 35-13-22-01-010 KIT (22) and install the new units as follows:

Install the adhesive reflective yellow washer into the bottom of the overboard-discharge indicator 5756HM2 (21). Make sure that the yellow side is out.
Attach the reflective green disc on its support and put this assembly on the overboard-discharge indicator 5756HM2 (21). Make sure that the green side is out.
Use PLIERS - CIRCLIP and install the retaining ring with its rounded edges in.

(h) Connect the LP oxygen-overpressure-hose 5762HM2 to the oxygen pressure-regulator/transmitter 4HT2 (20) as follows:

1 Remove the CAP - BLANKING, APPROVED FOR USE WITH OXYGEN from the LP overpressure port (12).
2 Install a new AIPC 35-12-81-11-010 RING FOR FLARED TUBE (13) on the union (14).
3 Install the union (14) on the LP overpressure port (12).
4 TORQUE the union (14) to between 3.95 and 3.05 m.daN (29.13 and 22.49 lbf.ft )

.
5 Identify the tightened union nuts with a red line (Ref. AMM TASK 20-23-22-910-001).
(i) Connect the HP oxygen-overpressure-hose 5761HM2 to the valve (15):

1 Remove the CAP - BLANKING, APPROVED FOR USE WITH OXYGEN from the HP overpressure outlet (18).
2 Install a new AIPC 35-12-81-11-030 RING FOR FLARED TUBE (16) on the union (17).
3 Install the union (17) on the HP overpressure outlet (18).
4 TORQUE the union (17) to between 2.7 and 1.9 m.daN (19.91 and 14.01 lbf.ft )

.
5 Identify the tightened union nuts with a red line (Ref. AMM TASK 20-23-22-910-001).

5. Close-up
Subtask 35-13-22-865-051-A ** ON A/C NOT FOR ALL

A. 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	OXYGEN/CREW/OXY/SPLY	1HT	HA01

Subtask 35-13-22-942-053-A ** ON A/C NOT FOR ALL

B. Put the aircraft back to its initial configuration.
(1) Turn the manual shutoff valves.

CAUTION: WHEN YOU OPEN THE MANUAL SHUTOFF VALVE ON THE CREW OXYGEN-STORAGE CYLINDER, MAKE SURE THAT:

YOU TURN IT VERY SLOWLY
YOU TURN IT UNTIL IT IS FULLY OPEN.

IF YOU TURN THE MANUAL SHUTOFF VALVE TOO QUICKLY, YOU CAN CAUSE DAMAGE TO THE EQUIPMENT. IF THE MANUAL SHUTOFF VALVE IS NOT FULLY OPEN, THE OXYGEN PRESSURE DATA CAN BE INCORRECT.

(a) Turn the manual shutoff valves of the crew oxygen-storage-cylinders 5750HM1 and 5750HM2 very slowly until they are fully open.
(2) Get access to the overboard-discharge indicators 5756HM1 (11) and 5756HM2 (21) from the outside of the aircraft.
(a) Make sure that you cannot see the adhesive reflective yellow washer.
(3) In the avionics compartment:
(a) Remove the WARNING NOTICE(S).
(4) In the cockpit:
(a) Remove the WARNING NOTICE(S).

Subtask 35-13-22-410-052-A ** ON A/C NOT FOR ALL

C. Close Access
(1) Make sure that the work area is clean and clear of tools and other items.
(2) Close access door 812 (Ref. AMM TASK 52-41-00-410-002).
(3) Remove the access platform(s).

[Rev.10 from 2021] 2026.04.01 01:04:39 UTC