Definition
An unintended deployment of a thrust reverser without pilot input, occurring in flight or on the ground. Because reverse thrust during flight directs engine thrust forward, an uncommanded reverse can produce sudden asymmetric thrust, severe yaw, loss of lift, and potential loss of control. Modern thrust reverser systems include multiple mechanical, hydraulic, and electronic interlocks specifically designed to prevent this condition.
Plain English
A thrust reverser deploys on its own, without the pilot selecting it. If this happens in flight, it can be extremely dangerous because the engine is suddenly pushing the airplane backward instead of forward.
Context Anchor
Seen in thrust reverser discussions, abnormal procedures, system failure warnings, and accident reports involving reverse thrust.
Derivation
“Uncommanded” combines “un-,” meaning “not,” with “commanded,” meaning ordered or directed. “Reverse” comes from the idea of turning back or acting in the opposite direction. Together, the term means reverse thrust happening without an intended order.
Why Pilots Care
It can create sudden loss of directional control on the runway, especially during landing or a rejected takeoff.
Grounding Statement
Picture one engine suddenly trying to slow its side of the airplane while the other side is still being pushed normally.
Intuition Check
Do not read “reverse” as the airplane flying backward. Here it means an engine redirecting its push forward to help slow the airplane, and “uncommanded” means that happened without a valid pilot or system command.
Example Sentence 1
The crew briefed the uncommanded reverse procedure as part of their pre-departure review.
Example Sentence 2
Pilots train to recognize an uncommanded reverse quickly and take steps to restore normal thrust.