Plain English Meaning

Getting the airplane down to a lower altitude quickly and safely because something serious has happened and staying high is no longer an option.

Full Definition

A maneuver used to descend an airplane from altitude as rapidly as possible, within structural and operating limits, in response to an in-flight emergency such as an uncontrollable fire, loss of cabin pressurization, or other condition that demands immediate descent to a lower altitude.

Context Anchor

Seen in descent training, emergency procedure practice, and real situations such as smoke, fire, loss of cabin , or another condition where staying high would make the worse.