Flameout
Encyclopedia
A flameout refers to the failure of a jet engine
caused by the extinction of the flame in the combustion chamber
. It can be caused by a number of factors, including fuel
exhaustion; compressor stall
; insufficient oxygen
supply; foreign object damage
(such as birds
, hail
or even volcanic ash
); severe inclement weather; and mechanical failure.
Early jet engines, such as Junkers Jumo 004
used in early German jets, including the Messerschmitt Me 262
, were at relatively high risk of flameout. Fast acceleration or inappropriate throttle settings could impoverish the fuel/air mixture
causing a flameout. If this happened at low altitude, it would often lead to the total loss of the aircraft. However, modern jets are engineered to a higher degree of technical quality and are controlled by systems (FADEC
) that constantly fine-tune their performance; as such flameouts are not such a risk as they were in the early days of jet-powered aviation.
of the aircraft to attempt to restart the engine. The procedure is designed to force air into the engine housing to spin the rotors and create enough pneumatic pressure for ignition. Typically in jet aircraft, to achieve the needed compression, airspeed of at least 300 knots (163.3 m/s) is required, at which point the engine may be able to restart. However, due to the significant loss of altitude required for the procedure, it is generally deemed a last resort.
Jet engine
A jet engine is a reaction engine that discharges a fast moving jet to generate thrust by jet propulsion and in accordance with Newton's laws of motion. This broad definition of jet engines includes turbojets, turbofans, rockets, ramjets, pulse jets...
caused by the extinction of the flame in the combustion chamber
Combustion chamber
A combustion chamber is the part of an engine in which fuel is burned.-Internal combustion engine:The hot gases produced by the combustion occupy a far greater volume than the original fuel, thus creating an increase in pressure within the limited volume of the chamber...
. It can be caused by a number of factors, including fuel
Fuel
Fuel is any material that stores energy that can later be extracted to perform mechanical work in a controlled manner. Most fuels used by humans undergo combustion, a redox reaction in which a combustible substance releases energy after it ignites and reacts with the oxygen in the air...
exhaustion; compressor stall
Compressor stall
A compressor stall is a situation of abnormal airflow resulting from a stall of the aerofoils within the compressor of a jet engine. Stall is found in dynamic compressors, particularly axial compressors, as used in jet engines and turbochargers for reciprocating engines.Compressor stalls result in...
; insufficient oxygen
Oxygen
Oxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...
supply; foreign object damage
Foreign object damage
Foreign Object Debris is a substance, debris or article alien to a vehicle or system which would potentially cause damage.Foreign Object Damage is any damage attributed to a foreign object that can be expressed in physical or economic terms that may or may not degrade the product's required...
(such as birds
Bird strike
A bird strike—sometimes called birdstrike, avian ingestion , bird hit, or BASH —is a collision between an airborne animal and a man-made vehicle, especially aircraft...
, hail
Hail
Hail is a form of solid precipitation. It consists of balls or irregular lumps of ice, each of which is referred to as a hail stone. Hail stones on Earth consist mostly of water ice and measure between and in diameter, with the larger stones coming from severe thunderstorms...
or even volcanic ash
Volcanic ash
Volcanic ash consists of small tephra, which are bits of pulverized rock and glass created by volcanic eruptions, less than in diameter. There are three mechanisms of volcanic ash formation: gas release under decompression causing magmatic eruptions; thermal contraction from chilling on contact...
); severe inclement weather; and mechanical failure.
Description
Flameouts occur most frequently when the engine is at an intermediate or low power setting (such as during the cruise and descent phases of flight). Most of the time, they are recovered from uneventfully. To recover from a flameout, the pilot should ensure the engine's fuel supply has been restored and then simply perform an engine restart as detailed in the aircraft's Flight Operations Manual.Early jet engines, such as Junkers Jumo 004
Junkers Jumo 004
The Jumo 004 was the world's first turbojet engine in production and operational use, and the first successful axial compressor jet engine ever built. Some 8,000 units were manufactured by Junkers in Germany during late World War II and powered the operational Messerschmitt Me 262 jet fighter,...
used in early German jets, including the Messerschmitt Me 262
Messerschmitt Me 262
The Messerschmitt Me 262 Schwalbe was the world's first operational jet-powered fighter aircraft. Design work started before World War II began, but engine problems prevented the aircraft from attaining operational status with the Luftwaffe until mid-1944...
, were at relatively high risk of flameout. Fast acceleration or inappropriate throttle settings could impoverish the fuel/air mixture
Air-fuel ratio
Air–fuel ratio is the mass ratio of air to fuel present in an internal combustion engine. If exactly enough air is provided to completely burn all of the fuel, the ratio is known as the stoichiometric mixture, often abbreviated to stoich...
causing a flameout. If this happened at low altitude, it would often lead to the total loss of the aircraft. However, modern jets are engineered to a higher degree of technical quality and are controlled by systems (FADEC
FADEC
Full Authority Digital Engine Control is a system consisting of a digital computer, called an electronic engine controller or engine control unit , and its related accessories that control all aspects of aircraft engine performance...
) that constantly fine-tune their performance; as such flameouts are not such a risk as they were in the early days of jet-powered aviation.
Windmill restart
A way to try and restart an engine that has experienced a flameout is by using a procedure called a windmill restart; this is a maneuver that uses the kinetic energyKinetic energy
The kinetic energy of an object is the energy which it possesses due to its motion.It is defined as the work needed to accelerate a body of a given mass from rest to its stated velocity. Having gained this energy during its acceleration, the body maintains this kinetic energy unless its speed changes...
of the aircraft to attempt to restart the engine. The procedure is designed to force air into the engine housing to spin the rotors and create enough pneumatic pressure for ignition. Typically in jet aircraft, to achieve the needed compression, airspeed of at least 300 knots (163.3 m/s) is required, at which point the engine may be able to restart. However, due to the significant loss of altitude required for the procedure, it is generally deemed a last resort.
Notable incidents of flameout
- On 6th August 1945 the top USAAF fighter aceFighter AceFighter Ace was a massively multiplayer online computer game in which one flies World War II fighter and bomber planes in combat against other players and virtual pilots...
Richard BongRichard BongRichard Ira "Dick" Bong is the United States' highest-scoring air ace, having shot down at least 40 Japanese aircraft during World War II. He was a fighter pilot in the U.S. Army Air Forces and a recipient of the Medal of Honor...
lost his life in a flight accident as his Lockheed P-80 Shooting Star fighter suffered a flame out and dived to ground.
- In June 1972, Jean Boulet piloted an Aérospatiale LamaAérospatiale Lama|-See also:-External links:...
helicopterHelicopterA helicopter is a type of rotorcraft in which lift and thrust are supplied by one or more engine-driven rotors. This allows the helicopter to take off and land vertically, to hover, and to fly forwards, backwards, and laterally...
to an absolute altitude recordFlight altitude recordThese are the records set for going the highest in the atmosphere from the age of ballooning onward. Some records are certified by Fédération Aéronautique Internationale.-Fixed-wing aircraft:-Piston-driven propeller aeroplane:...
of 12,442 meters (40,814 ft) http://records.fai.org/rotorcraft/aircraft.asp?id=188. At the extreme altitude the engine flamed out. The helicopter landed safely after the longest ever autorotationAutorotationIn aviation, autorotation refers to processes in both fixed-wing and rotary-wing aircraft. The term means significantly different things in each context....
in history.
- In a huge hailstorm in 1977, Southern Airways 242, a DC-9, lost both engines due to the hail. The plane landed on a highway and crashed into a gas station, killing 72.
- In 1982, British Airways Flight 9British Airways Flight 9British Airways Flight 9, sometimes referred to by its callsign Speedbird 9 or Jakarta incident, was a scheduled British Airways flight from London Heathrow to Auckland, with stops in Bombay, Madras, Kuala Lumpur, Perth, and Melbourne....
suffered flameouts in all four of its engines after flying through a cloud of pyroclastic materialPyroclastic flowA pyroclastic flow is a fast-moving current of superheated gas and rock , which reaches speeds moving away from a volcano of up to 700 km/h . The flows normally hug the ground and travel downhill, or spread laterally under gravity...
thrown up by the eruption of Mount Galunggung. The pilots were eventually able to restart three of the engines and make a safe landing.
- On 21 November 2002, during a routine test flight the Eurofighter DA6, a Spanish development prototype, crashed following an irrecoverable ‘double engine flame-out’ in flight; both crew members escaped unharmed.
- In 2004, Pinnacle Airlines Flight 3701Pinnacle Airlines Flight 3701Pinnacle Airlines Flight 3701 crashed on October 14, 2004, near Jefferson City, Missouri, United States. It was an overnight ferry flight from Little Rock, Arkansas, U.S. to Minneapolis-St. Paul International Airport, U.S...
suffered flameouts in both of its engines. The aircraft crashed near Jefferson City, Missouri after being unable to restart the engines. The pilot and co-pilot were both killed.
- In September 2007, while engaged in separation tests of the GBU-39 Small Diameter Bomb, an F-22 RaptorF-22 RaptorThe Lockheed Martin/Boeing F-22 Raptor is a single-seat, twin-engine fifth-generation supermaneuverable fighter aircraft that uses stealth technology. It was designed primarily as an air superiority fighter, but has additional capabilities that include ground attack, electronic warfare, and signals...
suffered a brief dual-engine flameout while performing a negative-g, 360 degree roll with eight SDBsSmall Diameter BombThe GBU-39 Small Diameter Bomb is a 250 pound guided bomb that is intended to provide aircraft with the ability to carry a higher number of bombs...
loaded in the weapons bay. The flameout occurred because the aircraft entered the maneuver with an incorrect trim setting. The engines were restarted almost immediately, allowing the pilot to remain in control of the aircraft and land at Edwards AFB, California, without further incident.