General Aircraft United Practice Test

The emergency cabin oxygen system is designed to deliver oxygen to all occupied areas of the aircraft, including both the cabin and the flight deck, in the event of a decompression. When cabin pressure rises or is lost, this system automatically supplies oxygen through fixed masks and distribution lines to everyone onboard for the required duration, ensuring crew and passengers can breathe while the aircraft descends to a safe altitude.

First aid oxygen is for medical use and typically not distributed to the whole cabin or cockpit. Supplemental oxygen is usually provided for individual use by crew or passengers and not automatically routed to both areas. A portable oxygen bottle also serves a single person or a few people, not the entire cabin and flight deck.