Boeing 747 oxygen system
Boeing 747 oxygen comes in three tiers: flight-crew quick-donning masks worn above FL250, cabin-crew protective breathing equipment, and passenger masks with chemical oxygen generators. Sizing assumes a pressurisation failure with a rapid descent to 10,000 ft.
Airliner oxygen on the 747 is delivered in layers: high-pressure demand masks for the two pilots, protective breathing equipment for the cabin crew, and chemical-generator masks that deploy from the ceiling for passengers.
| Key facts | |
|---|---|
| Flight crew | Quick-donning demand masks, mandatory above FL250 |
| Cabin crew | Protective breathing equipment (PBE) with its own generator |
| Passengers | Drop-down masks fed by chemical oxygen generators |
| Sizing case | Rapid descent to 10,000 ft plus continued supply to land |
Regulations require each flight-crew member on duty above FL250 to have a mask that can be donned quickly from its ready position and that supplies oxygen on demand; the pilot flying must wear oxygen at all times above FL250 unless quick-donning masks are fitted.
Passenger oxygen covers at least 10 percent of the seats with about a 30-minute supply, engineered to support a 10-minute descent to 10,000 ft followed by continued supply. Both crew and passenger systems are sized around survivable pressurisation failures.
Sources
- 14 CFR 121.333 supplemental oxygen — ECFR
- Chemical oxygen generator requirements — US Government Publishing Office
Sources
Facts on this page are checked against the primary and institutional references below.
- 14 CFR 121.333 supplemental oxygen — ECFR
- Chemical oxygen generator requirements — US Government Publishing Office
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