In a pressurized aircraft, how long must the supplemental oxygen supply be available for occupants other than pilots during a descent due to loss of cabin pressurization?

• A. 5 minutes
• B. 10 minutes
• C. 15 minutes
• D. 20 minutes

Answer: (B)

In a depressurization, non-pilot occupants must have a ready supply of supplemental oxygen long enough for the airplane to descend to a breathable cabin altitude. The minimum duration specified for this situation is ten minutes. This ensures there is enough time for the crew to execute a rapid descent to around 10,000 feet (or lower) while passengers continue to receive oxygen, reducing the risk of hypoxia or loss of consciousness during the descent. Shorter durations, like five minutes, could run out before the aircraft reaches a safe altitude, while longer durations aren’t required by the standard and aren’t necessary for the typical descent scenario.