In aviation, a flameout (or flame-out) is the run-down of a jet engine or other

turbine engine A gas turbine, also called a combustion turbine, is a type of continuous flow internal combustion engine. The main parts common to all gas turbine engines form the power-producing part (known as the gas generator or core) and are, in the directi ...

due to the extinction of the flame in its

combustor A combustor is a component or area of a gas turbine, ramjet, or scramjet engine where combustion takes place. It is also known as a burner, combustion chamber or flame holder. In a gas turbine engine, the ''combustor'' or combustion chamber is f ...

. The loss of flame can have a variety of causes, such as

fuel starvation In an internal combustion engine, fuel starvation is the failure of the fuel system to supply sufficient fuel to allow the engine to run properly, for example due to blockage, vapor lock, contamination by water, malfunction of the fuel pump or in ...

, excessive altitude,

compressor stall A compressor stall is a local disruption of the airflow in the compressor of a gas turbine or turbocharger. A stall that results in the complete disruption of the airflow through the compressor is referred to as a compressor surge. The severity of ...

foreign object damage In aviation and aerospace, foreign object debris (FOD), is any particle or substance, alien to an aircraft or system, which could potentially cause damage. External FOD hazards include bird strikes, hail, ice, sandstorms, ash-clouds or obje ...

deriving from birds, hail, or

volcanic ash Volcanic ash consists of fragments of rock, mineral crystals, and volcanic glass, created during volcanic eruptions and measuring less than 2 mm (0.079 inches) in diameter. The term volcanic ash is also often loosely used to refer ...

, severe

precipitation In meteorology, precipitation is any product of the condensation of atmospheric water vapor that falls under gravitational pull from clouds. The main forms of precipitation include drizzle, rain, sleet, snow, ice pellets, graupel and hail. ...

, mechanical failure, or very low ambient temperatures.

Engine control

Early jet engines were prone to flameout following disturbances of inlet airflow, or sudden or inappropriate

thrust lever Thrust levers or throttle levers are found in the cockpit of aircraft, and are used by the pilot, copilot, or autopilot to control the thrust output of the aircraft's engines, by controlling the fuel flow to those engines. In multi-engine air ...

movements, which resulted in incorrect air-fuel ratios in the combustion chamber. Modern engines are much more robust in this respect, and are often digitally controlled, which allows for a significantly more effective control of all engine parameters to prevent flameouts and even initiate an automatic restart if a flameout occurs. Flameouts occur most frequently at intermediate or low power settings such as in cruise and descent. To prevent a flameout when atmospheric or operational conditions are conducive to it, engine control systems usually provide a continuous ignition function. Ignitors are normally used only at engine start, until the flame in the combustion chamber becomes self-sustaining. With continuous ignition, instead, the ignitors are continually sparked every second or less, so that if a flameout occurs, combustion can immediately be restored.

Engine restart

Following a flameout, jet engines can normally be restarted in flight, provided the aircraft is flying within the portion of its

flight envelope In aerodynamics, the flight envelope, service envelope, or performance envelope of an aircraft or spacecraft refers to the capabilities of a design in terms of airspeed and load factor or atmospheric density, often simplified to altitude. The t ...

defined as the ''engine relight envelope''. Depending on where in the relight envelope the restart is attempted (that is depending on the aircraft's airspeed and altitude), the procedure may simply rely on the airflow (''windmill restart'') or require the use of the starter (''starter-assisted restart'') in order for the compressor to achieve sufficient rotational speed for successful ignition. For example, the

Airbus A320 The Airbus A320 family is a series of narrow-body airliners developed and produced by Airbus. The A320 was launched in March 1984, first flew on 22 February 1987, and was introduced in April 1988 by Air France. The first member of the famil ...

passenger jet has a maximum ceiling of over , but its certified engine relight envelope only extends to . Up to that altitude, a windmill restart can be attempted at airspeeds greater than ; below that speed, a starter-assisted relight is required.

Core lock Core lock is a jet engine failure that can happen to aircraft in flight. When an engine is shut down in flight, the design of the engine causes some parts to cool quicker than others. Since materials change sizes in different temperatures, this hap ...

can make restart impossible.

References

{{Authority control Aviation risks Jet engines