DOC AIRBUS | AMM A320FOXYGEN DISTRIBUTION - DESCRIPTION AND OPERATION
** ON A/C NOT FOR ALL
** ON A/C NOT FOR ALL
1. General
Each crew oxygen-distribution system supplies Low Pressure (LP) oxygen to two crew oxygen stations.
One LP oxygen-supply solenoid-valve controls each LP crew oxygen-distribution.
The LP oxygen-supply solenoid-valve has an electrical shutoff function between the oxygen supply sub-system and the downstream crew-oxygen-distribution sub-system.
Each system is mechanically isolated from the other system. Thus, if there is a malfunction in one of the systems, this will not have an effect on the other system.
** ON A/C NOT FOR ALL Each crew oxygen-distribution system supplies Low Pressure (LP) oxygen to two crew oxygen stations.
One LP oxygen-supply solenoid-valve controls each LP crew oxygen-distribution.
The LP oxygen-supply solenoid-valve has an electrical shutoff function between the oxygen supply sub-system and the downstream crew-oxygen-distribution sub-system.
Each system is mechanically isolated from the other system. Thus, if there is a malfunction in one of the systems, this will not have an effect on the other system.
2. Component Location
Distribution Manifold - Solenoid Valve - Low Pressure Switch - Test Port - Component Location ** ON A/C NOT FOR ALL
** ON A/C NOT FOR ALL Distribution Manifold - Solenoid Valve - Low Pressure Switch - Test Port - Component Location ** ON A/C NOT FOR ALL | FIN | FUNCTIONAL DESIGNATION | PANEL | ZONE | ACCESS DOOR | ATA REF |
|---|---|---|---|---|---|
| ** ON A/C NOT FOR ALL | |||||
| 5753HM1 | MANIFOLD DISTRIBUTION | 125 | 35-20-00 | ||
| 5753HM2 | MANIFOLD DISTRIBUTION | 126 | 35-20-00 | ||
| 3HT1 | LP SOLENOID SUPPLY VALVE | 125 | 35-13-51 | ||
| 3HT2 | LP SOLENOID SUPPLY VALVE | 126 | 35-13-51 | ||
| 4WV1 | PRESSURE SWITCH | 125 | 35-13-14 | ||
| 4WV2 | PRESSURE SWITCH | 125 | 35-13-14 | ||
| 5755HM1 | PORT.ASSY TEST | 125 | 35-13-41 | ||
| 5755HM2 | PORT.ASSY TEST | 126 | 35-13-41 | ||
| 10RN1 | STOWAGE BOX-OXY MASK, CAPT | 101VU | 211 | 35-12-41 | |
| 10RN2 | STOWAGE BOX-OXY MASK, F/O | 700VU | 212 | 35-12-41 | |
| 10RN3 | STOWAGE BOX-OXY MASK, 3RD OCCPNT | 700VU | 212 | 35-12-41 | |
| 5774HM | STOWAGE BOX-OXY MASK, 4TH OCCPNT | 211 | 35-12-41 | ||
| 5759HM | MASK-FULL FACE/Q.D. OXY, CAPT | 211 | 35-12-41 | ||
| 5758HM | MASK-FULL FACE/Q.D. OXY, F/O | 212 | 35-12-41 | ||
| 5757HM | MASK-FULL FACE/Q.D. OXY, 3RD OCCPNT | 210 | 35-12-41 | ||
| 5760HM | MASK-FULL FACE/Q.D. OXY, 4TH OCCPNT | 210 | 35-12-41 | ||
3. System Description
Each LP oxygen-distribution circuit includes:
** ON A/C NOT FOR ALL Each LP oxygen-distribution circuit includes:
- An electrical LP oxygen-supply solenoid-valve with a position switch
- A test port connected to the mechanical distribution manifold through a test line
- A mechanical distribution manifold with an oxygen low-pressure switch
- An LP supply distribution-line with stainless-steel rigid pipes and flexible hoses.
- Two full-face/quick-donning oxygen masks and their related stowage boxes.
- A full-face/quick-donning oxygen mask and its related stowage box.
4. Component Description
A. LP Oxygen-Supply Solenoid-Valve
The LP oxygen-supply solenoid-valve is installed between the pressure regulator/transmitter and the distribution manifold. A 28VDC signal opens/closes this valve (Ref. AMM D/O 35-13-00-00).
On the valve housing, an arrow shows the direction of the LP oxygen flow.
The valve has an integrated electronic circuit which changes the permanent control voltage into a pulse which operates the valve. When there is no pulse, the valve coil is not energized. The valve position agrees with the last control signal.
A switch sends the valve position data to the System Data Acquisition Concentrator (SDAC) (Ref. AMM D/O 31-54-00-00) for monitoring and display (Ref. AMM D/O 35-13-00-00).
The LP oxygen-supply solenoid-valve is installed between the pressure regulator/transmitter and the distribution manifold. A 28VDC signal opens/closes this valve (Ref. AMM D/O 35-13-00-00).
On the valve housing, an arrow shows the direction of the LP oxygen flow.
The valve has an integrated electronic circuit which changes the permanent control voltage into a pulse which operates the valve. When there is no pulse, the valve coil is not energized. The valve position agrees with the last control signal.
A switch sends the valve position data to the System Data Acquisition Concentrator (SDAC) (Ref. AMM D/O 31-54-00-00) for monitoring and display (Ref. AMM D/O 35-13-00-00).
(1) A test port:
The test port has an internal filter, an internal shutoff valve and a protective cap. The test port is used for the ground maintenance, for the pressure and leak tests of the LP part of the distribution system.
The test port has a maximum operating pressure of 102 psi (7.03 bar).
The test port has an internal filter, an internal shutoff valve and a protective cap. The test port is used for the ground maintenance, for the pressure and leak tests of the LP part of the distribution system.
The test port has a maximum operating pressure of 102 psi (7.03 bar).
C. LP Distribution Manifold
The LP distribution manifold is an aluminum-forged component.
The LP distribution manifold has the components and connections that follow:
The LP distribution manifold is an aluminum-forged component.
The LP distribution manifold has the components and connections that follow:
(1) An oxygen low-pressure switch:
The oxygen low-pressure switch senses if the pressure is too low in the LP distribution circuit. This switch sends an electrical signal to the SDAC for monitoring ( (Ref. AMM D/O 35-13-00-00)).
It operates at a pressure between 45 psi (3.10 bar) and 60 psi (4.14 bar).
The oxygen low-pressure switch senses if the pressure is too low in the LP distribution circuit. This switch sends an electrical signal to the SDAC for monitoring ( (Ref. AMM D/O 35-13-00-00)).
It operates at a pressure between 45 psi (3.10 bar) and 60 psi (4.14 bar).
(2) Connections:
- An LP inlet port to which the oxygen comes from the LP supply solenoid-valve.
- An LP outlet port from which the oxygen goes through the LP oxygen-distribution lines and is supplied to the oxygen mask stowage-boxes.
- An LP outlet port from which the oxygen goes through the test line. The test port is connected at the end of this test line.
D. Oxygen-Mask Stowage Boxes
The oxygen-mask stowage boxes are installed in the cockpit, adjacent to each flight crew station. Each stowage box is the connection point for the full-face/quick-donning oxygen mask.
The oxygen-mask stowage boxes are installed in the cockpit, adjacent to each flight crew station. Each stowage box is the connection point for the full-face/quick-donning oxygen mask.
(1) Stowage box
Each stowage box includes:
Each stowage box includes:
- A connector for the LP oxygen supply
- An electrical plug for the radio connection
- A two-flap door, which keeps the mask in its housing
- A PRESS TO TEST AND RESET control button on the left flap of the door
- A pneumatic supply valve, which operates when you open the door or when you push the PRESS TO TEST AND RESET control button
- An oxygen flow indicator, which flashes when the LP oxygen flows
- An OXY ON flag, which shows that the doors are closed and the LP oxygen continues to supply the mask.
(2) Connection of the mask
Each stowage box has:
Each stowage box has:
- A flexible hose which connects the box oxygen valve to the mask. One end has a quick-disconnect connection with a self-sealing coupling. This coupling prevents oxygen leakage when the mask is disconnected and removed.
- A microphone lead with a quick-disconnect device for the connection to the radio communication system.
E. Full-Face/Quick-Donning Oxygen Mask
The full-face/quick-donning oxygen mask is an emergency breathing equipment that protects the eyes and respiratory system of the crew members.
It is necessary in the conditions that follow:
The mask has the parts that follow:
The full-face/quick-donning oxygen mask is an emergency breathing equipment that protects the eyes and respiratory system of the crew members.
It is necessary in the conditions that follow:
- Cockpit depressurization
- Smoke and poisonous fumes.
The mask has the parts that follow:
(1) Mask and goggles assembly
The mask face piece is a full-face piece that protects the eyes, nose, mouth and respiratory system of the crew members.
The mask has a plastic window.
The mask window has a protective film to prevent damage to it when you remove the mask from its stowage box for cleaning or maintenance.
This protective film is made of electrostatic adhesive soft plastic. You can remove it easily with its side strip.
The protective film must not be on the mask when the aircraft is in service.
The mask face piece is a full-face piece that protects the eyes, nose, mouth and respiratory system of the crew members.
The mask has a plastic window.
The mask window has a protective film to prevent damage to it when you remove the mask from its stowage box for cleaning or maintenance.
This protective film is made of electrostatic adhesive soft plastic. You can remove it easily with its side strip.
The protective film must not be on the mask when the aircraft is in service.
(2) Inflatable harness
The harness keeps the mask and goggles assembly in position on the user's head. The harness is made of elastomer tubes which expand with oxygen pressure. The mask is stored in its stowage box with the harness deflated.
When the mask is removed, the harness inflation control-plates are manually pushed. Then, the pneumatic harness inflates with oxygen pressure.
When the harness is inflated, it gets the diameter and rigidity necessary to put it on correctly.
When the user releases the harness control plates, the harness is depressurized and it keeps the mask tightly against the user's face.
The harness keeps the mask and goggles assembly in position on the user's head. The harness is made of elastomer tubes which expand with oxygen pressure. The mask is stored in its stowage box with the harness deflated.
When the mask is removed, the harness inflation control-plates are manually pushed. Then, the pneumatic harness inflates with oxygen pressure.
When the harness is inflated, it gets the diameter and rigidity necessary to put it on correctly.
When the user releases the harness control plates, the harness is depressurized and it keeps the mask tightly against the user's face.
(3) Microphone
In the distribution valve of the stowage box, a pressure switch is used to operate the microphone when the LP oxygen flows in the mask (Ref. AMM D/O 35-13-00-00).
In the distribution valve of the stowage box, a pressure switch is used to operate the microphone when the LP oxygen flows in the mask (Ref. AMM D/O 35-13-00-00).
(4) Regulator
The mask regulator controls the distribution of oxygen in the mask:
The mask regulator controls the distribution of oxygen in the mask:
- Air/oxygen mixture with an altimetric automatic control
- 100% pure oxygen
- 100% pure oxygen with overpressure
- Overpressure manual control.
(5) Flexible supply hose
The oxygen supply hose connects the mask to the stowage box with a quick-disconnect coupling.
The oxygen supply hose connects the mask to the stowage box with a quick-disconnect coupling.
F. Distribution Lines
Distribution Manifold - Solenoid Valve - Low Pressure Switch - Test Port - Component Location ** ON A/C NOT FOR ALL
Each distribution line is made with rigid aluminum pipes and flexible (PTFE) hoses.
The two distribution lines supply oxygen to the flight crew stations.
One line supplies the Captain and Third Occupant stations. The other line supplies the First Officer station.
Flexible hoses make the connection to the stowage box assemblies.
Distribution Manifold - Solenoid Valve - Low Pressure Switch - Test Port - Component Location ** ON A/C NOT FOR ALL The two distribution lines supply oxygen to the flight crew stations.
One line supplies the Captain and Third Occupant stations. The other line supplies the First Officer station.
Flexible hoses make the connection to the stowage box assemblies.
5. Operation/Control and Indicating
A. Mask Regulator
The mask regulator is of the pilot-valve type and has these functions:
The mask regulator is of the pilot-valve type and has these functions:
(1) Air and oxygen mixture (normal operation)
When the N/100% rocker switch is in the N position, the user breathes a mixture of air and oxygen. The position of the air/oxygen mixing aneroid-capsule controls the quantity of external air. This capsule is fully closed at a cabin altitude of 35000 ft. (10668 m) and the pilot breathes 100% oxygen.
When the N/100% rocker switch is in the N position, the user breathes a mixture of air and oxygen. The position of the air/oxygen mixing aneroid-capsule controls the quantity of external air. This capsule is fully closed at a cabin altitude of 35000 ft. (10668 m) and the pilot breathes 100% oxygen.
(2) 100% oxygen supply without overpressure
When the N/100% rocker switch is in the 100% position, the user breathes pure oxygen at all altitudes.
When the N/100% rocker switch is in the 100% position, the user breathes pure oxygen at all altitudes.
(3) Emergency function
Overpressure is necessary for breathing if there is smoke or poisonous gas in the cockpit.
The user turns the PRESS TO TEST/EMERGENCY knob to get a continuous oxygen-overpressure flow.
A 100% oxygen selection is necessary to operate this overpressure function (rocker switch in 100% position).
Overpressure is necessary for breathing if there is smoke or poisonous gas in the cockpit.
The user turns the PRESS TO TEST/EMERGENCY knob to get a continuous oxygen-overpressure flow.
A 100% oxygen selection is necessary to operate this overpressure function (rocker switch in 100% position).
(4) Functional test
The PRESS TO TEST/EMERGENCY knob is used to do a functional test of the regulator.
This test is possible when the mask is stowed in its housing, but the user must push the PRESS TO TEST AND RESET button (on the stowage box) at the same time.
The PRESS TO TEST/EMERGENCY knob is used to do a functional test of the regulator.
This test is possible when the mask is stowed in its housing, but the user must push the PRESS TO TEST AND RESET button (on the stowage box) at the same time.
B. Mask
In emergency conditions (smoke or poisonous gas in the cockpit), a vent valve releases a small quantity of oxygen from the mask cavity into the goggles cavity. This increases the pressure in the mask and thus, smoke or fumes cannot go into it.
In emergency conditions (smoke or poisonous gas in the cockpit), a vent valve releases a small quantity of oxygen from the mask cavity into the goggles cavity. This increases the pressure in the mask and thus, smoke or fumes cannot go into it.