The damaged fan disk of the engine that catastrophically failed on United Airlines Flight 232

A turbine engine failure occurs when a turbine engine unexpectedly stops producing power due to a malfunction other than fuel exhaustion. It often applies for aircraft, but other turbine engines can fail, like ground-based turbines used in power plants or combined diesel and gas vessels and vehicles.


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 tens of thousands of hours of operation.[1] 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 of one per 375,000 flight hours, compared to of one every 3,200 flight hours for aircraft piston engines.[2] 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".[3] Continental Motors reports the FAA states general aviation engines experience one failures or IFSD every 10,000 flight hours, and states its Centurion engines is one per 20,704 flight hours, lowering to one per 163,934 flight hours in 2013–2014.[4]

The General Electric GE90 has an in-flight shutdown rate (IFSD) of one per million engine flight-hours.[5] The Pratt & Whitney Canada PT6 is known for its reliability with an in-flight shutdown rate of one per 333,333 hours from 1963 to 2016,[6] lowering to one per 651,126 hours over 12 months in 2016.[7]

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.


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, 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.[8]

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 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 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. While this situation can be alarming, the engine may recover with no damage.[9]

Other events that can happen with jet engines, such as a fuel control fault, can result in excess fuel in the engine's combustor. 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.[citation needed]

Also, the failure of certain components in the engine may result in a release of oil into bleed air that can cause an odor or oily mist in the cabin. This is known as a fume event. The dangers of fume events are the subject of debate in both aviation and medicine.[10]

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, bird strikes 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.[11]

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, 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.[12] 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.[citation needed]

Failure during extended operations

Main article: ETOPS

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.[13]

Contained and uncontained failures

The engine of Delta Air Lines Flight 1288 after it experienced catastrophic uncontained compressor rotor failure in 1996.

Engine failures may be classified as either as "contained" or "uncontained".

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.[15] Under Part 33, engine manufacturers are required to perform blade off tests to ensure containment of shrapnel if blade separation occurs.[16] Blade fragments exiting the inlet or exhaust can still pose a hazard to the aircraft, and this should be considered by the aircraft designers.[15] 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.[15]

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.[17] 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.[17]

Notable uncontained engine failure accidents


  2. ^ Steven E. Scates (September 2007). "Aerial Perspective: Flying Dollars and Sense". Professional Surveyor Magazine.
  3. ^ "Aircraft ReciprocatingEngine Failure: An Analysis of Failure in a Complex Engineered System" (PDF). Australian Transport Safety Bureau. 2007.
  4. ^ "Continental: 4 Million Diesel Flight Hours" (Press release). Continental Motors. 10 April 2014.
  5. ^ "Record Year for the World's Largest, Most Powerful Jet Engine" (Press release). GE Aviation. 19 January 2012.
  6. ^ "A Discussion with Pratt & Whitney Canada President John Saabas". AirInsight. 9 June 2016. Archived from the original on 17 August 2016. Retrieved 23 May 2019.
  7. ^ Mike Gerzanics (6 June 2016). "Flight test: Upgraded Pilatus PC-12 powers ahead". flightglobal.
  8. ^ Rotorcraft Flying Handbook (PDF). U.S. Government Printing Office, Washington D.C.: U.S. Federal Aviation Administration. 2000. p. 30. ISBN 1-56027-404-2. FAA-8083-21. a helicopter can be landed safely in the event of an engine failure
  9. ^ "Airplane Turbofan Engine Operation and Malfunctions Basic Familiarization for Flight Crews". Federal Aviation Administration. Archived from the original (DOC) on 22 April 2023. Retrieved 4 January 2024.
  10. ^ Nassauer, Sarah (30 July 2009). "Up in the Air: New Worries About 'Fume Events' on Planes". The Wall Street Journal. Retrieved 4 January 2024.
  11. ^ "Technical Report on Propulsion System and APU-Related Aircraft Safety Hazards" (PDF). Federal Aviation Administration. Retrieved 31 December 2012.
  12. ^ "Aeronatutical Information Manual". Transport Canada. Retrieved 29 December 2012.
  13. ^ "ETOPS, EROPS and Enroute Alternates" (PDF). The Boeing Company. Retrieved 31 December 2012.
  14. ^ "Uncontained Engine Failure - SKYbrary Aviation Safety". Retrieved 5 May 2018.
  15. ^ a b c d "FAA Advisory Circular AC 33-5: Turbine Engine Rotor Blade Containment/Durability" (PDF). Retrieved 10 December 2020.
  16. ^ Blade containment and rotor unbalance tests. Archived 12 June 2011 at the Wayback Machine, 14 CFR 33.94, 1984
  17. ^ a b "Four Recent Uncontained Engine Failure Events Prompt NTSB to Issue Urgent Safety Recommendations to FAA". Retrieved 27 May 2010. Public Domain This article incorporates text from this source, which is in the public domain.
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  21. ^ "Lessons of Manchester runway fire". 23 August 2010. Retrieved 5 July 2018.
  22. ^ "ASN Aircraft accident Tupolev 154M RA-85656 Mamony". 3 January 1994. Retrieved 18 April 2018.
  23. ^ "Катастрофа Ту-154М а/к 'Байкал' в районе Иркутска (борт RA-85656), 03 января 1994 года. // - авиационные происшествия, инциденты и авиакатастрофы в СССР и России - факты, история, статистика". Retrieved 18 April 2018.
  24. ^ " - News, search and shopping from the Houston Chronicle". 11 May 2009. Archived from the original on 11 May 2009. Retrieved 18 April 2018.
  25. ^ "Qantas grounds A380s after scare". BBC News. 4 November 2010. Retrieved 18 April 2018.
  26. ^ Phipps, Claire (9 September 2015). "British Airways plane catches fire at Las Vegas airport #BA2276". the Guardian. Retrieved 18 April 2018.
  27. ^ Shapiro, Emily (28 October 2016). "20 Injured After American Airlines Plane Catches Fire at Chicago's O'Hare Airport". ABC News. Retrieved 29 October 2016.
  28. ^ Editorial, Reuters (30 September 2017). "Air France flight with engine damage makes emergency landing in Canada". Reuters. Retrieved 18 April 2018. ((cite news)): |first= has generic name (help)
This article contains text from a publication of the United States National Transportation Safety Board. which can be found here [1] 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).