Decompression
Loss of cabin pressure at altitude: oxygen masks drop, crew grab the nearest one, and the pilots descend to breathable air.
Definition
Decompression is a loss of the pressurised cabin environment, either rapid — a burst door seal or structural failure, with a bang, fog and a rush of air — or slow, from a pressurisation system fault that crew may only notice through ear discomfort or the mask deployment. At cruise altitude the time of useful consciousness can be under a minute, so passenger masks drop automatically when cabin altitude climbs past a set threshold and the pilots fly an emergency descent to around 10,000 feet.
What it means for you
The rule you are drilled on is brutal in its simplicity: take the nearest oxygen mask immediately and do not move to help anyone until the aircraft levels off, because an unconscious crew member helps nobody. After the descent, your job becomes the cabin — checking passengers, moving those without oxygen, treating ear and sinus injuries and preparing for the diversion that almost always follows.
In practice
In a Qatar Airways recurrent scenario the cabin mock-up simulates a rapid decompression at cruise: masks drop, the crew grab the nearest portable or drop-down unit, brace in a seat and wait for the flight deck's all-clear before moving.
Go deeper
Related terms
4 terms- First aidSafety & trainingThe medical training and kit that make cabin crew the first responders to any illness or injury at 38,000 feet.
- DiversionFlight operationsLanding at an airport other than the planned destination — for weather, a technical fault, fuel or a medical emergency on board.
- SEPSafety & trainingSafety and Emergency Procedures — the core safety syllabus every cabin crew member is trained and re-examined on.
- TurbulenceSafety & trainingIrregular air movement that shakes the aircraft — the leading cause of in-flight injury, mostly to unbelted passengers and working crew.