cabin pressure loss

Cabin pressure loss is a drop in the air pressure maintained inside an aircraft during flight.

At cruising altitude, the outside air is too thin to breathe, so cabins are pressurized to simulate lower altitudes.

When pressure drops—through a leak, structural failure, or system malfunction—oxygen masks deploy and pilots descend rapidly to breathable altitude.

The crew declared an emergency after cabin pressure loss at 35,000 feet.