Turbine engine failure: Difference between revisions

A '''turbine engine failure''' occurs when a [[Gas turbine|turbine engine]] unexpectedly stops producing [[Power (physics)|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 [[reliability (engineering)|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.<ref>{{cite web|url= https://www.poentetechnical.com/news/what-is-the-lifespan-of-an-airplanes-engine/ |title= What is the Lifespan of an Airplane's Engine?|date= 13 January 2023}}</ref> 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.<ref>{{cite news |url= https://archives.profsurv.com/magazine/article.aspx?i=1950 |title= Aerial Perspective: Flying Dollars and Sense |work= Professional [[Surveyor]] Magazine |date= September 2007 |author= Steven E. Scates}}</ref>{{Unreliable source?|date=July 2024|certain=y|reason=Source is a magazine article which makes the same statement without reference to any verifiable FAA statements or data}}

[[Continental Motors, Inc.|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 {{Format price|{{#expr:100000/4.83round0}}}} flight hours, lowering to one per {{Format price|{{#expr:100000/0.61round0}}}} flight hours in 2013-20142013–2014.<ref>{{cite press release |url= http://www.continentaldiesel.com/typo3/index.php?id=106&Year=2014&NewsID=112&L=1 |date= 10 April 2014 |title= Continental: 4 Million Diesel Flight Hours |publisher= Continental Motors}}</ref>

The [[Pratt & Whitney Canada PT6]] is known for its reliability with an in-flight shutdown rate of one per {{Format price|{{#expr:1000000/3round0}}}} hours from 1963 to 2016,<ref name=AirInsightJune2016>{{cite news |url= http://airinsight.com/2016/06/09/discussion-pratt-whitney-canada-president-john-saabas/ |title= A Discussion with Pratt & Whitney Canada President John Saabas |publisher= AirInsight |date= 9 June 2016 |access-date= 23 May 2019 |archive-date= 17 August 2016 |archive-url= https://web.archive.org/web/20160817084047/http://airinsight.com/2016/06/09/discussion-pratt-whitney-canada-president-john-saabas/ |url-status= dead }}</ref> lowering to one per {{Format price|651126}} hours over 12 months in 2016.<ref>{{cite news |url= https://www.flightglobal.com/news/articles/flight-test-upgraded-pilatus-pc-12-powers-ahead-426092/ |title= Flight test : Upgraded Pilatus PC-12 powers ahead |publisher= flightglobal |date= 6 June 2016 |author= Mike Gerzanics}}</ref>

[[Turboprop]]-powered aircraft and [[turboshaft]]-powered [[helicopter]]s are also powered by [[Gas turbine|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.<ref name=FAA>{{cite book | title = Rotorcraft Flying Handbook | year = 2000 | publisher = U.S. [[Federal Aviation Administration]] | location = U.S. Government Printing Office, Washington D.C. | id = FAA-8083-21 | page = 30 | url=http://www.faa.gov/regulations_policies/handbooks_manuals/aircraft/media/faa-h-8083-21.pdf | quote=''a helicopter can be landed safely in the event of an engine failure'' | ISBNisbn= 1-56027-404-2}}</ref>

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 engine|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 [[turbine|blade]]. While this situation can be alarming, the engine may recover with no damage.<ref>{{cite web |url=https://www.faa.gov/aircraft/air_cert/design_approvals/engine_prop/media/engine_malf_famil.doc |format=DOC |title=Airplane Turbofan Engine Operation and Malfunctions Basic Familiarization for Flight Crews |website=[[Federal Aviation Administration]] |url-status=dead |archive-url=https://web.archive.org/web/20230422050236/https://www.faa.gov/aircraft/air_cert/design_approvals/engine_prop/media/engine_malf_famil.doc |archive-date=April 22, 2023 |access-date=January 4, 2024}}</ref>

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 [[aviation medicine|medicine]].<ref name=WSJ>{{cite web |last=Nassauer |first=Sarah |url=https://www.wsj.com/articles/SB10001424052970204900904574302293012711628 | title=Up in the Air: New Worries About 'Fume Events' on Planes | publisher=[[The Wall Street Journal]]| date=30 July 30, 2009 | access-date=29January December4, 20122024 | authorurl-access=Sarah Nassauerlimited}}</ref>

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

* A contained engine failure is one in which all internal rotating components mightremain separatewithin insideor embedded in the engine's butcase either(including remainany withincontainment wrapping that is part of the engine's cases), or exit the engine through the tail pipe,<ref>{{Cite web|url=https://www.skybrary.aero/index.php/Uncontained_Engine_Failure|title=Uncontained Engine Failure - SKYbrary Aviation Safety|website=www.skybrary.aero|language=en|access-date=2018-05-05}}</ref> or air inlet.<ref name="AC_33-5">{{Cite web|url=https://www.faa.gov/documentLibrary/media/Advisory_Circular/AC_33-5.pdf|title=FAA Advisory Circular AC 33-5: Turbine Engine Rotor Blade Containment/Durability|website=www.faa.gov|language=en|access-date=2020-12-10}}</ref>

EngineThe casesvery arespecific nottechnical designeddistinction tobetween containa failedcontained turbineand disks.uncontained Insteadengine failure derives from regulatory requirements for design, thetesting, riskand certification of uncontainedaircraft diskengines failureunder isPart mitigated33 byof designatingthe disksU.S. as[[Federal safety-criticalAviation partsRegulations]], definedwhich ashas thealways partsrequired ofturbine anaircraft engineengines whoseto failurebe is likelydesigned to presentcontain adamage directresulting hazardfrom torotor theblade aircraftfailure.<ref name="NTSB Investigative Report 2AC_33-5" /> EngineUnder manufacturersPart are33, requiredengine bymanufacturers theare FAArequired to perform [[Blade off testing|blade off tests]] to ensure containment of shrapnel if blade separation occurs.<ref name="14CFR">[http://ecfr.gpoaccess.gov/cgi/t/text/text-idx?c=ecfr&sid=466022f9e574a12e0b383c9ddebced01&rgn=div8&view=text&node=14:1.0.1.3.16.6.363.13&idno=14 Blade containment and rotor unbalance tests.] {{webarchive|url=https://web.archive.org/web/20110612142218/http://ecfr.gpoaccess.gov/cgi/t/text/text-idx?c=ecfr&sid=466022f9e574a12e0b383c9ddebced01&rgn=div8&view=text&node=14%3A1.0.1.3.16.6.363.13&idno=14 |date=12 June 2011 }}, 14 CFR 33.94, 1984</ref> Blade fragments exiting the inlet or exhaust can still pose a hazard to the aircraft, and this should be considered by the aircraft designers.<ref name="AC_33-5" /> A nominally contained engine failure can still result in engine [[parts departing aircraft|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.

* Two [[LOT Polish Airlines]] flights, both [[Ilyushin Il-62]]s, suffered catastrophic uncontained engine failures in the 1980s. The first was in 1980 on [[LOT Polish Airlines Flight 7]] where flight controls were destroyed, killing all 87 on board. In 1987, on [[LOT Polish Airlines Flight 5055]], the failure of 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 eventuala crash, whichthat 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.<ref>{{cite journal |author=Antoni Milkiewicz|title=Jeszcze o Lesie Kabackim |trans-title=More on the Kabacky Forest |language=pl |date=October 1991 |journal=Aero : technikaTechnika lotniczaLotnicza |location=Warsaw|publisher=Oficyna Wydawnicza Simp-Simpress|pages=12–14|issn=0867-6720}}</ref>

* The [[Aeroflot Flight 3519|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.

* [[United Airlines Flight 232]]: a [[McDonnell Douglas DC-10]] 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 [[Flying an airplane without control surfaces|differential thrust]]. There were 111 fatalities. Prior to the United 232this crash, the probability of a simultaneous failure of all three hydraulic systems was considered as low as one in a billion. However, the [[statistical model]]s used to come up with this figure did not account for the factposition thatof the number-two engine was, mounted at the tail close to all the hydraulic lines, nor the possibilityresults thatof anfragments engine failure would release many fragmentsreleased in many directions. Since then, more modern aircraft engine designs have focused on keeping shrapnel from penetratingpuncturing the [[cowling]] or ductwork, and have increasingly utilizedutilizing high-strength [[composite material]]s to achieve the required penetration resistance while keeping the weight low.{{citation needed|date=May 2019}}

* [[Qantas Flight 32]]: an [[Airbus A380]] flying from London Heathrow to Sydney (via Singapore) in 2010 had an uncontained failure in a [[Rolls-Royce Trent 900]] 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.<ref>{{cite webnews|url=https://www.bbc.com/news/world-asia-pacific-11691197|title=Qantas grounds A380s after scare|work=BBC News|date=4 November 2010|access-date=18 April 2018|via=www.bbc.com}}</ref>

* [[SouthwestAmerican Airlines Flight 3472383 (2016)|American Airlines Flight 383]]: a [[Boeing 737767-700300ER]] flying from New OrleansChicago to OrlandoMiami in 2016 suffered an uncontained engine failure on its #12 engine (General Electric CF6) during climbtakeoff resulting in a puncturelarge tofire leftwhich side ofdestroyed the fuselageouter causing a loss of cabin pressure and damage to theright wing and empennage. The aircraft divertedaborted totakeoff Pensacolaand Internationalwas Airport,evacuated Floridawith for21 aminor safeinjuries, landingbut onno runwayfatalities.<ref>{{cite 17news|last1=Shapiro|first1=Emily|title=20 aboutInjured 20After minutesAmerican laterAirlines withoutPlane furtherCatches incident.Fire Thereat wereChicago's noO'Hare injuries.<ref>{{citeAirport |work=ABC News web|url=https://wwwabcnews.ntsbgo.govcom/_layoutsUS/ntsb.aviationamerican-airlines-flight-catches-fire-chicagos-ohare-airport/brief.aspxstory?ev_idid=20160827X31134&key=1 43143000|titleaccess-date=DCA16FA21729 |publisher=Ntsb.govOctober 2016|date=28 October 2016-08-27 |access-date=2018-04-18}}</ref>