What is a rapid decompression?

• A. A gradual loss of cabin pressure
• B. A sudden loss of cabin pressure, taking less than 10 seconds to equalize with outside pressure
• C. A leak that lasts several minutes
• D. A minor pressure drop without equalization

Answer: (B)

Rapid decompression means a sudden, rapid drop in cabin pressure due to a breach or failure that allows outside air to rush in. The key feature is how quickly the cabin pressure becomes equal to the outside pressure, which happens in just a few seconds. That abrupt change is what distinguishes rapid decompression from a slow or gradual loss of pressure.

So this option matches best because it describes a sudden loss of cabin pressure and specifies that the pressure equalizes with the outside environment in less than about ten seconds, capturing both the abruptness and the rapid equalization.

The other descriptions describe slower or less dramatic situations: a gradual loss takes time to develop; a leak lasting minutes implies a slow, persistent leak rather than a rapid event; a minor pressure drop without equalization doesn’t reflect the rapid exchange with outside air that defines decompression.