Oxygen Supply
There are 3 independent sources of Oxygen:
- Flight Crew Oxygen in the flight deck
- Passenger Oxygen in the overhead passenger service units
- Portable Oxygen tanks throughout the cabin for emergency use
Controls and indications are in the flight deck, on the overhead panel.
Flight Crew Oxygen
The FC oxygen system is designed to provide pilots and observers with oxygen in the event of pressure emergencies or smoke.
The oxygen is stored in a single cylinder located in the E&E compartment. Flow is controlled by a regulator that provides low pressure oxygen to the masks.
The pressure is indicated on the aft overhead panel. Minimum oxygen pressure requirements are determined in the QRH Performance In-flight Section, based on the ambient temperature.
A selection of those is presented here:
| Bottle Temperature | Number | Of | Crew |
|---|---|---|---|
| C | 2 | ||
| 25 | 485 | 680 | 870 |
| 15 | 470 | 655 | 840 |
| 5 | 455 | 635 | 815 |
Note that an oxygen pressure of 500 psi is sufficient for two crew members up to 30 degrees ambient temperatures. The oxygen pressure gauge measures from 0 to 2000 psi, but pressure may be as high as 1,850 psi.
There is a green discharge indicator disk on the bottom right side, indicating thermal discharge.
Each flight crew position includes a quick-don oxygen masks with a diluter-demand regulator and a self-adjusting pneumatic harness, while the two flight deck observer seats have regular oxygen masks with independent smoke goggles.
There are 3 modes of oxygen deliver:
- Normal: ambient air mixed with O2
- 100%: 100% demand oxygen
- Regulator selector can be set to EMER 100% O2 under pressure.
When the left oxygen panel door is opened, the mask microphone is enabled and the boom microphone is disabled. The microphone is then used like the boom microphone using the ACP.
To re-enable the boom mic and disable the mask mic, close the oxygen panel door and push the TEST/RESET Switch. Note that the mask does not need to be stowed.
The stowage doors can be closed without shutting the O2 supply; to shut it off push the TEST/RESET switch. Note that this is a maintenance function at WestJet.
Passenger Oxygen
The passenger ixtgen system provides emergency oxygen for pasengers, CCMs, and lav occupants. It consists of individual chemical generators andd oyxgen masks.
It is activated by:
- Automatic pressure switch at cabin altitude of 14,000 ft, or
- Activating the PASS OXYGEN switch is placed to on in the Aft Overhead
- This defines whether masks are deployed automatically or manually; either auto “in Normal” or to “on”.
There are 4 masks above all passenger seats, while each FA station and each lavatory contains 2 masks.
Each oxygen module contains its own chemical generator, which begins to operate when a mask is pulled. This will also cause the other masks to drop and will fire a fire pin to start the generation of oxygen.
Once the generator begins, 100% oxygen will begin to flow for approximately 12 minutes, and cannot be shut off. Because these generators produce heat in excess of 260 degrees C, they may produce light smoke and some odours.
Portable Oxygen
These bottles are pressures to 1800 PSI and provide 30 min of oxygen. Can be used as first aidd or emergency walk-around. Each of these contain:
- Pressure flow selector
- Low pressure port
- High pressure port
- Pressure gauge
- Oxygen mask
A single high pressure oxygen cylinder provides O2 for::Only the flight deck crew. What is the maximum pressure for the flight crew oxygen system?::1850 psi. The O2 mask microphone is disabled and the boom microphone is enabled when the left O2 mask panel door is closed and the TEST/RESET Switch is pushed::True. How is the individual oxygen shutoff valve closed after stowing the flight deck O2 mask and closing the left panel door?::By pressing the TEST/RESET switch. At what cabin altitude will passenger O2 masks deploy automatically?::14,000 ft.