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An engine failure occurs when one or more engines on an aircraft stop functioning normally. This is often assumed to mean a complete loss of power from the engine, but partial power loss and excess power are also engine failures.

An engine failure is any failure of an engine to produce power normally as commanded by the pilot. There are three main scenarios:

  • The engine stops producing power completely
  • The engine produces less power than commanded (partial power loss)
  • The engine produces more power than commanded

In basic pilot training in a single-engine aircraft, an "engine failure" almost always means a complete power loss from the engine, but pilots may train for other scenarios. If an engine stops because of fuel exhaustion or starvation, it is not usually considered to be an engine failure.

The response to an engine failure depends on how many engines the aircraft has and what the nature of the failure is. All powered aircraft have checklists and procedures for use in the event of engine failure, although if the failure occurs at a low altitude there may be little time to use them and therefore pilots are expected to memorize the most critical actions to take.

In a single-engine aircraft, if the engine fails completely the pilot will typically trim the aircraft to glide as efficiently as possible and then execute an emergency landing; if time allows he may run through an engine failure checklist or attempt to restart the engine.

In a multi-engine aircraft, the pilot will first stabilize the aircraft - to compensate for the asymmetric thrust from the remaining engine(s) - and then run a checklist, plan a diversion to an alternate landing site or take other action as required.

Engine failure on takeoff is a specific scenario in pilot training and a real failure is considered very challenging to handle because the pilot must react immediately with limited time and altitude available.

Use this tag for questions about training for or handling engine failures in any aircraft.

For more information, see the Wikipedia articles on:

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