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A turbine engine failure occurs when a
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 direct ...
unexpectedly stops producing
power Power most often refers to: * Power (physics), meaning "rate of doing work" ** Engine power, the power put out by an engine ** Electric power * Power (social and political), the ability to influence people or events ** Abusive power Power may ...
due to a malfunction other than
fuel exhaustion 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 ...
. It often applies for
aircraft An aircraft is a vehicle that is able to fly by gaining support from the air. It counters the force of gravity by using either static lift or by using the dynamic lift of an airfoil, or in a few cases the downward thrust from jet engines. ...
, but other turbine engines can fail, like ground-based turbines used in power plants or
combined diesel and gas Combined diesel and gas (CODAG) is a type of propulsion system for ships that need a maximum speed that is considerably faster than their cruise speed, particularly warships like modern frigates or corvettes. Pioneered by Germany with the , a C ...
vessels and vehicles.


Reliability

Turbine engines in use on today's turbine-powered aircraft are very reliable. Engines operate efficiently with regularly scheduled inspections and maintenance. These units can have lives ranging in the thousands of hours of operation. However, engine malfunctions or failures occasionally occur that require an engine to be shut down in flight. Since multi-engine airplanes are designed to fly with one engine inoperative and flight crews are trained to fly with one engine inoperative, the in-flight shutdown of an engine typically does not constitute a serious safety of flight issue. The Federal Aviation Administration (FAA) was quoted as stating turbine engines have a
failure rate Failure rate is the frequency with which an engineered system or component fails, expressed in failures per unit of time. It is usually denoted by the Greek letter λ (lambda) and is often used in reliability engineering. The failure rate of a ...
of one per 375,000 flight hours, compared to of one every 3,200 flight hours for aircraft piston engines. Due to "gross under-reporting" of general aviation piston engines in-flight shutdowns (IFSD), the FAA has no reliable data and assessed the rate "between 1 per 1,000 and 1 per 10,000 flight hours". Continental Motors reports the FAA states general aviation engines experience one failures or IFSD every 10,000 flight hours, and states its
Centurion engines The Thielert Centurion is a series of Diesel cycle aircraft engines for general aviation originally built by Thielert, which was bought by Aviation Industry Corporation of China's Tecnify Motors subsidiary and is currently marketed by Contin ...
is one per flight hours, lowering to one per flight hours in 2013-2014. The General Electric GE90 has an in-flight shutdown rate (IFSD) of one per million engine flight-hours. The
Pratt & Whitney Canada PT6 The Pratt & Whitney Canada PT6 is a turboprop aircraft engine produced by Pratt & Whitney Canada. Its design was started in 1958, it first ran in February 1960, first flew on 30 May 1961, entered service in 1964 and has been continuously upda ...
is known for its reliability with an in-flight shutdown rate of one per hours from 1963 to 2016, lowering to one per hours over 12 months in 2016.


Emergency landing

Following an engine shutdown, a precautionary landing is usually performed with airport fire and rescue equipment positioned near the runway. The prompt landing is a precaution against the risk that another engine will fail later in the flight or that the engine failure that has already occurred may have caused or been caused by other as-yet unknown damage or malfunction of aircraft systems (such as fire or damage to aircraft flight controls) that may pose a continuing risk to the flight. Once the airplane lands, fire department personnel assist with inspecting the airplane to ensure it is safe before it taxis to its parking position.


Rotorcraft

Turboprop-powered aircraft and turboshaft-powered helicopters are also powered by turbine engines and are subject to engine failures for many similar reasons as jet-powered aircraft. In the case of an engine failure in a helicopter, it is often possible for the pilot to enter
autorotation Autorotation is a state of flight in which the main rotor system of a helicopter or other rotary-wing aircraft turns by the action of air moving up through the rotor, as with an autogyro, rather than engine power driving the rotor. Bensen, Igor ...
, using the unpowered rotor to slow the aircraft's descent and provide a measure of control, usually allowing for a safe emergency landing even without engine power.


Shutdowns that are not engine failures

Most in-flight shutdowns are harmless and likely to go unnoticed by passengers. For example, it may be prudent for the
flight crew Aircrew, also called flight crew, are personnel who operate an aircraft while in flight. The composition of a flight's crew depends on the type of aircraft, plus the flight's duration and purpose. Commercial aviation Flight deck positions ...
to shut down an engine and perform a precautionary landing in the event of a low oil pressure or high oil temperature warning in the cockpit. However, passengers in a jet powered aircraft may become quite alarmed by other engine events such as a
compressor surge 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 t ...
— a malfunction that is typified by loud bangs and even flames from the engine's inlet and tailpipe. A compressor surge is a disruption of the airflow through a gas turbine jet engine that can be caused by engine deterioration, a crosswind over the engine's inlet, ice accumulation around the engine inlet, ingestion of foreign material, or an internal component failure such as a broken
blade A blade is the portion of a tool, weapon, or machine with an edge that is designed to puncture, chop, slice or scrape surfaces or materials. Blades are typically made from materials that are harder than those they are to be used on. Histori ...
. While this situation can be alarming, the engine may recover with no damage. Other events that can happen with jet engines, such as a fuel control fault, can result in excess fuel in the engine's
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 ...
. This additional fuel can result in flames extending from the engine's exhaust pipe. As alarming as this would appear, at no time is the engine itself actually on fire. Also, the failure of certain components in the engine may result in a release of oil into
bleed air Bleed air is compressed air taken from the compressor stage of a gas turbine upstream of its fuel-burning sections. Automatic air supply and cabin pressure controller (ASCPCs) valves bleed air from high or low stage engine compressor sections. Low ...
that can cause an odor or oily mist in the cabin. This is known as a
fume event A fume event occurs when bleed air used for cabin pressurization and air conditioning in a pressurized aircraft is contaminated by fluids such as engine oil, hydraulic fluid, anti-icing fluid, and other potentially hazardous chemicals. How cab ...
. The dangers of fume events are the subject of debate in both aviation and medicine.


Possible causes

Engine failures can be caused by mechanical problems in the engine itself, such as damage to portions of the turbine or oil leaks, as well as damage outside the engine such as fuel pump problems or fuel contamination. A turbine engine failure can also be caused by entirely external factors, such as
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 ...
,
bird strike A bird strike—sometimes called birdstrike, bird ingestion (for an engine), bird hit, or bird aircraft strike hazard (BASH)—is a collision between an airborne animal (usually a bird or bat) and a moving vehicle, usually an aircraft. The term ...
s or weather conditions like precipitation or icing. Weather risks such as these can sometimes be countered through the usage of supplementary ignition or anti-icing systems.


Failures during takeoff

A turbine-powered aircraft's takeoff procedure is designed around ensuring that an engine failure will not endanger the flight. This is done by planning the takeoff around three critical
V speeds In aviation, V-speeds are standard terms used to define airspeeds important or useful to the operation of all aircraft. These speeds are derived from data obtained by aircraft designers and manufacturers during flight testing for aircraft type- ...
, V1, VR and V2. V1 is the critical engine failure recognition speed, the speed at which a takeoff can be continued with an engine failure, and the speed at which stopping distance is no longer guaranteed in the event of a rejected takeoff. VR is the speed at which the nose is lifted off the runway, a process known as rotation. V2 is the single-engine safety speed, the single engine climb speed. The use of these speeds ensure that either sufficient thrust to continue the takeoff, or sufficient stopping distance to reject it will be available at all times.


Failure during extended operations

In order to allow twin-engined aircraft to fly longer routes that are over an hour from a suitable diversion airport, a set of rules known as ETOPS (Extended Twin-engine Operational Performance Standards) is used to ensure a twin turbine engine powered aircraft is able to safely arrive at a diversionary airport after an engine failure or shutdown, as well as to minimize the risk of a failure. ETOPS includes maintenance requirements, such as frequent and meticulously logged inspections and operation requirements such as flight crew training and ETOPS-specific procedures.


Contained and uncontained failures

Engine failures may be classified as either as "contained" or "uncontained". * A contained engine failure is one in which all internal rotating components remain within or embedded in the engine's case (including any containment wrapping that is part of the engine), or exit the engine through the tail pipe or air inlet. * An uncontained engine event occurs when an engine failure results in fragments of rotating engine parts penetrating and escaping through the engine case. The very specific technical distinction between a contained and uncontained engine failure derives from regulatory requirements for design, testing, and certification of aircraft engines under Part 33 of the U.S. Federal Aviation Regulations, which has always required turbine aircraft engines to be designed to contain damage resulting from rotor blade failure. Under Part 33, engine manufacturers are required to perform blade off tests to ensure containment of shrapnel if blade separation occurs.Blade containment and rotor unbalance tests.
, 14 CFR 33.94, 1984
Blade fragments exiting the inlet or exhaust can still pose a hazard to the aircraft, and this should be considered by the aircraft designers. Note that a nominally contained engine failure can still result in engine parts departing the aircraft as long as the engine parts exit via the existing openings in the engine inlet or outlet, and do not create new openings in the engine case containment. Fan blade fragments departing via the inlet may also cause airframe parts such as the inlet duct and other parts of the engine nacelle to depart the aircraft due to deformation from the fan blade fragment's residual kinetic energy. The containment of failed rotating parts is a complex process which involves high energy, high speed interactions of numerous locally and remotely located engine components (e.g., failed blade, other blades, containment structure, adjacent cases, bearings, bearing supports, shafts, vanes, and externally mounted components). Once the failure event starts, secondary events of a random nature may occur whose course and ultimate conclusion cannot be precisely predicted. Some of the structural interactions that have been observed to affect containment are the deformation and/or deflection of blades, cases, rotor, frame, inlet, casing rub strips, and the containment structure. Uncontained turbine engine disk failures within an aircraft engine present a direct hazard to an airplane and its crew and passengers because high-energy disk fragments can penetrate the cabin or fuel tanks, damage flight control surfaces, or sever flammable fluid or hydraulic lines. Engine cases are not designed to contain failed turbine disks. Instead, the risk of uncontained disk failure is mitigated by designating disks as safety-critical parts, defined as the parts of an engine whose failure is likely to present a direct hazard to the aircraft.


Notable uncontained engine failure accidents

*
National Airlines Flight 27 National Airlines Flight 27 was a scheduled passenger flight between Miami, Florida and San Francisco, California with intermediate stops at New Orleans, Louisiana; Houston, Texas; and Las Vegas, Nevada, in the United States. On November 3, 1973 ...
: a
McDonnell Douglas DC-10 The McDonnell Douglas DC-10 is an American trijet wide-body aircraft manufactured by McDonnell Douglas. The DC-10 was intended to succeed the DC-8 for long- range flights. It first flew on August 29, 1970; it was introduced on August 5, 19 ...
flying from Miami to San Francisco in 1973 had an overspeed failure of a General Electric CF6-6, resulting in one fatality. * Two LOT Polish Airlines flights, both
Ilyushin Il-62 The Ilyushin Il-62 (russian: Илью́шин Ил-62; NATO reporting name: Classic) is a Soviet long-range narrow-body jetliner conceived in 1960 by Ilyushin. As successor to the popular turboprop Il-18 and with capacity for almost 200 pas ...
s, suffered catastrophic uncontained engine failures in the 1980s. The first was in 1980 on
LOT Polish Airlines Flight 7 LOT Polish Airlines Flight 007 was an Ilyushin Il-62 that crashed near Okęcie Airport in Warsaw, Poland, on 14 March 1980, as the crew aborted a landing and attempted to go-around. All 87 crew and passengers died. It was caused by the disinteg ...
where flight controls were destroyed, killing all 87 on board. In 1987, on
LOT Polish Airlines Flight 5055 LOT Polish Airlines Flight 5055 was a scheduled international passenger flight from Warsaw, Poland, to New York City, United States. In the late-morning hours of 9 May 1987, the Ilyushin Il-62M operating the flight crashed in the Kabaty Woods na ...
, the aircraft's inner left (#2) engine, damaged the outer left (#1) engine, setting both on fire and causing loss of flight controls, leading to an eventual crash, which killed all 183 people on board. In both cases, the turbine shaft in engine #2 disintegrated due to production defects in the engines' bearings, which were missing rollers. * The Tu-154 crash near Krasnoyarsk was a major aircraft crash that occurred on Sunday, December 23, 1984 in the vicinity of Krasnoyarsk. The Tu-154B-2 airliner of the 1st Krasnoyarsk united aviation unit (Aeroflot) performed passenger flight SU-3519 on the Krasnoyarsk-Irkutsk route, but during the climb, engine No. 3 failed. The crew decided to return to the airport of departure, but during the landing approach a fire broke out, which destroyed the control systems and as a result, the plane crashed to the ground 3200 meters from the threshold of the runway of the Yemelyanovo airport and collapsed. Of the 111 people on board (104 passengers and 7 crew members), one survived. The cause of the catastrophe was the destruction of the disk of the first stage of the low pressure circuit of engine No. 3, which occurred due to the presence of fatigue cracks. The cracks were caused by a manufacturing defect – the inclusion of a titanium-nitrogen compound that has a higher microhardness than the original material. The methods used at that time for the manufacture and repair of disks, as well as the means of control, were found to be partially obsolete, which is why they did not ensure the effectiveness of control and detection of such a defect. The defect itself arose probably due to accidental ingestion of a titanium sponge or charge for smelting an ingot of a piece enriched with nitrogen. * Cameroon Airlines Flight 786: a
Boeing 737 The Boeing 737 is a narrow-body aircraft produced by Boeing at its Renton Factory in Washington. Developed to supplement the Boeing 727 on short and thin routes, the twinjet retains the 707 fuselage width and six abreast seating with two u ...
flying between Douala and Garoua, Cameroon in 1984 had a failure of a
Pratt & Whitney JT8D The Pratt & Whitney JT8D is a low-bypass (0.96 to 1) turbofan engine introduced by Pratt & Whitney in February 1963 with the inaugural flight of the Boeing 727. It was a modification of the Pratt & Whitney J52 turbojet engine which powered the ...
-15 engine. Two people died. *
British Airtours Flight 28M British Airtours Flight 28M (also known as Flight 328) was an international passenger flight which caught fire before takeoff at Manchester Airport, England on 22 August 1985 with the loss of 55 lives. It was en route to Corfu International Ai ...
: a Boeing 737 flying from Manchester to Corfu in 1985 suffered an uncontained engine failure and fire on takeoff. The takeoff was aborted and the plane turned onto a taxiway and began evacuating. Fifty-five passengers and crew were unable to escape and died of smoke inhalation. The accident led to major changes to improve the survivability of aircraft evacuations. * United Airlines Flight 232: a
McDonnell Douglas DC-10 The McDonnell Douglas DC-10 is an American trijet wide-body aircraft manufactured by McDonnell Douglas. The DC-10 was intended to succeed the DC-8 for long- range flights. It first flew on August 29, 1970; it was introduced on August 5, 19 ...
flying from Denver to Chicago in 1989. The failure of the rear General Electric CF6-6 engine caused the loss of all hydraulics, forcing the pilots to attempt a landing using differential thrust. There were 111 fatalities. Prior to this crash, the probability of a simultaneous failure of all three hydraulic systems was considered as low as one in a billion. However,
statistical model A statistical model is a mathematical model that embodies a set of statistical assumptions concerning the generation of sample data (and similar data from a larger population). A statistical model represents, often in considerably idealized form, ...
s did not account for the position of the number-two engine, mounted at the tail close to hydraulic lines, nor the results of fragments released in many directions. Since then, aircraft engine designs have focused on keeping shrapnel from puncturing the
cowling A cowling is the removable covering of a vehicle's engine, most often found on automobiles, motorcycles, airplanes, and on outboard boat motors. On airplanes, cowlings are used to reduce drag and to cool the engine. On boats, cowlings are a cove ...
or ductwork, increasingly utilizing high-strength composite materials to achieve penetration resistance while keeping the weight low. *
Baikal Airlines Flight 130 Baikal Airlines Flight 130 was a scheduled domestic passenger flight from Irkutsk to Moscow that crashed on 3 January 1994. The plane involved in the crash was a Tupolev Tu-154 operated by Russian airline Baikal Airlines. The plane was carrying 1 ...
: a starter of engine No. 2 on a Tu-154 heading from Irkutsk to Domodedovo, Moscow in 1994, failed to stop after engine startup and continued to operate at over 40,000 rpm with open bleed valves from engines, which caused an uncontained failure of the starter. A detached turbine disk damaged fuel and oil supply lines (which caused fire) and hydraulic lines. The fire-extinguishing system failed to stop the fire, and the plane diverted back to Irkutsk. However, due to loss of hydraulic pressure the crew lost control of the plane, which subsequently crashed into a dairy farm killing all 124 on board and one on the ground. * On June 8, 1995, a DC-9-32 doing service as, ValuJet Flight 597, suffered an uncontained engine failure of the 7th stage high pressure compressor disk due to inadequate inspection of the corroded disk. The resulting rupture caused jet fuel to flow into the cabin and ignite, and the fire caused the jet to be a write-off. *
Delta Air Lines Flight 1288 Delta Air Lines Flight 1288 was a regularly scheduled flight from Pensacola, Florida, to Atlanta, Georgia. On July 6, 1996, the aircraft serving the flight, a McDonnell Douglas MD-88, was on takeoff roll from Runway 17 at Pensacola when it exp ...
: a
McDonnell Douglas MD-88 The McDonnell Douglas MD-80 is a series of five-abreast single-aisle airliners developed by McDonnell Douglas. It was produced by the developer company until August 1997 and then by Boeing Commercial Airplanes. The MD-80 was the second gener ...
flying from Pensacola, Florida to Atlanta in 1996 had a cracked compressor rotor hub failure on one of its
Pratt & Whitney JT8D The Pratt & Whitney JT8D is a low-bypass (0.96 to 1) turbofan engine introduced by Pratt & Whitney in February 1963 with the inaugural flight of the Boeing 727. It was a modification of the Pratt & Whitney J52 turbojet engine which powered the ...
-219 engines. Two died. * TAM Flight 9755: a Fokker 100, departing Recife/Guararapes–Gilberto Freyre International Airport for São Paulo/Guarulhos International Airport on 15 September 2001, suffered an uncontained engine failure (Rolls-Royce RB.183 Tay) in which fragments of the engine shattered three cabin windows, causing decompression and pulling a passenger partly out of the plane. Another passenger held the passenger in until the aircraft landed, but the passenger blown out of the window died. *
Qantas Flight 32 Qantas Flight 32 was a regularly scheduled passenger flight from London to Sydney via Singapore. On 4 November 2010, the aircraft operating the route, an Airbus A380, suffered an uncontained failure in one of its four Rolls-Royce Trent 900 ...
: an
Airbus A380 The Airbus A380 is a large wide-body airliner that was developed and produced by Airbus. It is the world's largest passenger airliner and only full-length double-deck jet airliner. Airbus studies started in 1988, and the project was annou ...
flying from London Heathrow to Sydney (via Singapore) in 2010 had an uncontained failure in a
Rolls-Royce Trent 900 The Rolls-Royce Trent 900 is a high-bypass turbofan produced by Rolls-Royce plc to power the Airbus A380, competing with the Engine Alliance GP7000. Initially proposed for the Boeing 747-500/600X in July 1996, this first application was late ...
engine. The failure was found to have been caused by a misaligned counter bore within a stub oil pipe leading to a fatigue fracture. This in turn led to an oil leakage followed by an oil fire in the engine. The fire led to the release of the Intermediate Pressure Turbine (IPT) disc. The airplane, however, landed safely. This led to the grounding of the entire Qantas A380 fleet. *
British Airways Flight 2276 British Airways Flight 2276 was a scheduled international passenger service from Las Vegas to London. On 8 September 2015, the Boeing 777-200ER operating the flight suffered an uncontained engine failure and fire in the left ( #1) GE90 engine ...
: a
Boeing 777-200ER The Boeing 777, commonly referred to as the Triple Seven, is an American long-range wide-body airliner developed and manufactured by Boeing Commercial Airplanes. It is the world's largest twinjet. The 777 was designed to bridge the gap betw ...
flying from Las Vegas to London in 2015 suffered an uncontained engine failure on its #1 GE90 engine during takeoff, resulting in a large fire on its port side. The aircraft successfully aborted takeoff and the plane was evacuated with no fatalities. * American Airlines Flight 383: a
Boeing 767-300ER The Boeing 767 is an American wide-body aircraft developed and manufactured by Boeing Commercial Airplanes. The aircraft was launched as the 7X7 program on July 14, 1978, the prototype first flew on September 26, 1981, and it was certified o ...
flying from Chicago to Miami in 2016 suffered an uncontained engine failure on its #2 engine (General Electric CF6) during takeoff resulting in a large fire which destroyed the outer right wing. The aircraft aborted takeoff and was evacuated with 21 minor injuries, but no fatalities. *
Air France Flight 66 Air France Flight 066 was a scheduled international passenger flight from Paris Charles de Gaulle Airport to Los Angeles International Airport, operated by Air France and using an Airbus A380-861. On 30 September 2017, the aircraft suffered an ...
: an
Airbus A380 The Airbus A380 is a large wide-body airliner that was developed and produced by Airbus. It is the world's largest passenger airliner and only full-length double-deck jet airliner. Airbus studies started in 1988, and the project was annou ...
, registration F-HPJE performing flight from Paris, France, to Los Angeles, United States, was en route about southeast of Nuuk, Greenland, when it suffered a catastrophic engine failure in 2017 (General Electric / Pratt & Whitney Engine Alliance GP7000). The crew descended the aircraft and diverted to Goose Bay, Canada, for a safe landing about two hours later.


References

{{reflist :''This article contains text from a publication of the United States National Transportation Safety Board. which can be found her

As a work of the United States Federal Government, the source is in the public domain and may be adapted freely per USC Title 17; Chapter 1; §105 (see Wikipedia:Public Domain).''
Turbines Jet engines Aviation safety Aviation risks Emergency aircraft operations Aircraft engines