DOC AIRBUS | AMM A320FCONTROL AND INDICATING - DESCRIPTION AND OPERATION
** ON A/C NOT FOR ALL
1. General
The crew oxygen system has control and indicating functions.
In the cockpit, on the OXYGEN section of the overhead control and indicating panel 21VU, the CREW SUPPLY pushbutton switch controls the opening of the two Low Pressure (LP) oxygen-supply solenoid valves (3HT1 and 3HT2) at the same time.
The system pressure status and pressure warnings are shown on:
** ON A/C NOT FOR ALL The crew oxygen system has control and indicating functions.
In the cockpit, on the OXYGEN section of the overhead control and indicating panel 21VU, the CREW SUPPLY pushbutton switch controls the opening of the two Low Pressure (LP) oxygen-supply solenoid valves (3HT1 and 3HT2) at the same time.
The system pressure status and pressure warnings are shown on:
- A direct-reading pressure gage installed on each crew oxygen-storage cylinder
- An overboard discharge indicator
- The ECAM Display Units (DUs) (DOOR/OXY page on the lower ECAM DU and warning/resolution messages on the Engine/Warning Display (EWD)).
2. Component Location
** ON A/C NOT FOR ALL | FIN | FUNCTIONAL DESIGNATION | PANEL | ZONE | ACCESS DOOR | ATA REF |
|---|---|---|---|---|---|
| ** ON A/C NOT FOR ALL | |||||
| 5755HM1 | PORT.ASSY TEST | 125 | 35-13-41 | ||
| 5755HM2 | PORT.ASSY TEST | 126 | 35-13-41 | ||
| 5756HM1 | IND.DISCHARGE | 125 | 35-13-22 | ||
| 5756HM2 | IND.DISCHARGE | 126 | 35-13-22 | ||
| 4WV1 | PRESSURE SWITCH | 125 | 35-13-14 | ||
| 4WV2 | PRESSURE SWITCH | 125 | 35-13-14 | ||
| 3HT1 | LP SOLENOID SUPPLY VALVE | 125 | 35-13-51 | ||
| 3HT2 | LP SOLENOID SUPPLY VALVE | 126 | 35-13-51 | ||
| 4HT | XMTR/PRESS REG-OXY | 125 | 35-13-15 | ||
| 4HT2 | PRESS.TRANSM.REGULATO | 126 | 35-13-15 | ||
SchematicA. Controls
(1) CREW SUPPLY pushbutton switch:
In the cockpit, on the OXYGEN section of the overhead control and indicating panel 21VU, the CREW SUPPLY pushbutton switch sends a 28VDC control signal to the two LP oxygen-supply solenoid valves (3HT1 and 3HT2) at the same time.
Thus, the LP oxygen-supply solenoid valves open and the LP oxygen flows in the two distribution circuits.
The 28VDC ESS BUS busbar 801PP supplies the CREW SUPPLY pushbutton switch through circuit breaker 1HT.
A switch sends a signal for the position of the LP oxygen-supply solenoid valves to the two System Data Acquisition Concentrators (SDACs) for monitoring and display.
In the cockpit, on the OXYGEN section of the overhead control and indicating panel 21VU, the CREW SUPPLY pushbutton switch sends a 28VDC control signal to the two LP oxygen-supply solenoid valves (3HT1 and 3HT2) at the same time.
Thus, the LP oxygen-supply solenoid valves open and the LP oxygen flows in the two distribution circuits.
The 28VDC ESS BUS busbar 801PP supplies the CREW SUPPLY pushbutton switch through circuit breaker 1HT.
A switch sends a signal for the position of the LP oxygen-supply solenoid valves to the two System Data Acquisition Concentrators (SDACs) for monitoring and display.
(2) System Data Acquisition Concentrator (SDAC)
(Ref. AMM D/O 31-54-00-00).
Each SDAC receives the High Pressure (HP) oxygen values from the HP chambers of the oxygen pressure regulator/transmitters (4HT and 4HT2).
If an LP switch (4WV1 or 4WV2) is activated, it sends a signal to the SDAC.
Thus, each SDAC also receives the LP oxygen status.
Then, each SDAC transmits these HP oxygen values (and the LP oxygen status if an LP switch is activated) to the DOOR/OXY page of the lower ECAM DU.
(Ref. AMM D/O 31-54-00-00).
Each SDAC receives the High Pressure (HP) oxygen values from the HP chambers of the oxygen pressure regulator/transmitters (4HT and 4HT2).
If an LP switch (4WV1 or 4WV2) is activated, it sends a signal to the SDAC.
Thus, each SDAC also receives the LP oxygen status.
Then, each SDAC transmits these HP oxygen values (and the LP oxygen status if an LP switch is activated) to the DOOR/OXY page of the lower ECAM DU.
(3) System test
Two test ports (5755HM1 and 5755HM2) are used for the pressure and leak tests on the ground.
The test ports are connected through tubes to the LP distribution manifolds (5753HM1 and 5753HM2).
Two test ports (5755HM1 and 5755HM2) are used for the pressure and leak tests on the ground.
The test ports are connected through tubes to the LP distribution manifolds (5753HM1 and 5753HM2).
B. Indicating
(1) HP oxygen indicator
The HP oxygen value is shown on the direct-reading pressure gage of each valve assembly of the crew oxygen-storage cylinder.
There is no compensation in temperature for this HP value.
The HP oxygen value is shown on the direct-reading pressure gage of each valve assembly of the crew oxygen-storage cylinder.
There is no compensation in temperature for this HP value.
(2) Overboard discharge indicators
Each oxygen circuit has an overboard discharge line.
If there is too much pressure in the HP or in the LP oxygen circuit, the overpressure is released out of the aircraft through an overboard discharge line.
When the overpressure flows to the outside, the green disc (that you can usually see on the overboard discharge indicator, out of the aircraft) breaks and a yellow reflective area replaces the green disc.
The overboard discharge indicator of the Captain oxygen circuit is between FR12 and FR13, on the left side.
The overboard discharge indicator of the First Officer oxygen-circuit is between FR17 and FR18, on the left side.
The green disc breaks at a pressure between 40 psi (2.76 bar) and 100 psi (6.89 bar).
Each oxygen circuit has an overboard discharge line.
If there is too much pressure in the HP or in the LP oxygen circuit, the overpressure is released out of the aircraft through an overboard discharge line.
When the overpressure flows to the outside, the green disc (that you can usually see on the overboard discharge indicator, out of the aircraft) breaks and a yellow reflective area replaces the green disc.
The overboard discharge indicator of the Captain oxygen circuit is between FR12 and FR13, on the left side.
The overboard discharge indicator of the First Officer oxygen-circuit is between FR17 and FR18, on the left side.
The green disc breaks at a pressure between 40 psi (2.76 bar) and 100 psi (6.89 bar).
(3) CREW SUPPLY pushbutton switch
When the distribution circuits operate, the white OFF legend of the CREW SUPPLY pushbutton switch goes off.
When the distribution circuits are closed, the white OFF legend of the CREW SUPPLY pushbutton switch comes on.
When the distribution circuits operate, the white OFF legend of the CREW SUPPLY pushbutton switch goes off.
When the distribution circuits are closed, the white OFF legend of the CREW SUPPLY pushbutton switch comes on.
C. Lower ECAM DU
On the DOOR/OXY page of the lower ECAM DU, on the upper right part, you can see the indications that follow:
On the DOOR/OXY page of the lower ECAM DU, on the upper right part, you can see the indications that follow:
(1) HP values of the crew oxygen-storage cylinders
There is no compensation in temperature for these HP values. These HP values come into view in:
There is no compensation in temperature for these HP values. These HP values come into view in:
- Green when they are equal to or more than 500 psi (34.47 bar).
- Pulsing in green when the values are between 200 psi (13.79 bar) and 499 psi (34.40 bar).
- Amber when the values are less than 200 psi (13.79 bar).
(2) Amber half-box
There is an amber half-box around the HP oxygen value of the applicable crew oxygen-storage cylinder, in the two conditions that follow:
There is an amber half-box around the HP oxygen value of the applicable crew oxygen-storage cylinder, in the two conditions that follow:
- The HP oxygen value is less than 800 psi (55.16 bar), and
- The aircraft is in flight phase 1, 2, 9 or 10.
NOTE: If the Flight Warning Computer (FWC) is not valid, the amber half-box is shown in all the flight phases.
(3) REGUL (1), (2) or (1+2) LO PR message
This message comes into view in amber below the HP oxygen values in the two conditions that follow:
If only the LP switch 4WV1 operates, the REGUL 1 LO PR message comes into view.
If only the LP switch 4WV2 operates, the REGUL 2 LO PR message comes into view.
If the two LP switches (4WV1 and 4WV2) operate, the REGUL 1+2 LO PR message comes into view.
This message comes into view in amber below the HP oxygen values in the two conditions that follow:
- One and/or two LP switches (4WV1 and/or 4WV2) operate and send an LP oxygen status to the ECAM, and
- There is a confirmation time of this LP oxygen status of five seconds.
If only the LP switch 4WV1 operates, the REGUL 1 LO PR message comes into view.
If only the LP switch 4WV2 operates, the REGUL 2 LO PR message comes into view.
If the two LP switches (4WV1 and 4WV2) operate, the REGUL 1+2 LO PR message comes into view.
(4) CKPT OXY legend
In normal conditions, the CKPT OXY legend is white.
The CKPT OXY legend becomes amber if:
In normal conditions, the CKPT OXY legend is white.
The CKPT OXY legend becomes amber if:
- The LP switches (4WV1 and/or 4WV2) sense an LP oxygen status, or
- The LP oxygen-supply solenoid valves (3HT and 3HT2) are closed (they are closed if the CREW SUPPLY pushbutton switch is in the OFF position), or
- A minimum of one HP oxygen value is less than 200 psi (13.79 bar), or
- At minimum of one HP oxygen value is not available and is replaced with an amber XX legend.