A flame out (sometimes one word, 'flameout') is an event that can occur in jet engines
and qualifies as a Very Bad Thing
. In essence, if the airflow
flow through a jet (a turbojet
, or turbofan
) engine is disrupted sufficiently, the engine will stall
. In other words, the 'flame goes out.' This may also be accompanied by a burst of flame from the engine as unburnt fuel which has accumulated with the disrupted airflow ignites. Since most jet aircraft have the gliding
characteristics of a large gold brick
, it is imperative that the engine be restarted as soon as possible to avoid UFIT
, or Uncontrolled Flight Into Terrain. In order to restart the engine, the aircraft must be maneuvered
so that its flight profile forces a steady airflow through the engine.
In some cases, the aircraft may enter a condition whereby the airflow over the control surfaces is disrupted to the point that they become useless, depriving the pilot of the means to adjust the aircraft's attitude. One example of this sequence of events is the flat spin shown in the movie Top Gun when Iceman's jetwash causes Maverick and Goose's aircraft's engines to flame out. After losing power, they enter a flat spin, and Maverick is unable to recover, forcing them to eject.
This is further complicated by the fact that on modern jet aircraft, the flight control surfaces are nearly always moved by hydraulic or other assisted actuators which require power to operate, and that power is typically derived from a generate run by - you guessed it - the jet engine, or a parasite turbine which requires smooth airflow along the fuselage in order to function. Hence, if the aircraft has flamed out and entered one of these uncontrolled flight regimes, things get Very Bad Very Fast.