Airbus A380 VH-OQA, the plane involved in the accident |
|
| Accident summary | |
|---|---|
| Date | 4 November 2010 |
| Type | Uncontained engine failure |
| Passengers | 440[1] |
| Crew | 29[1] |
| Injuries | 0 |
| Fatalities | 0 |
| Survivors | 469 (all) |
| Aircraft type | Airbus A380-842[2] |
| Aircraft name | Nancy Bird Walton |
| Operator | Qantas |
| Tail number | VH-OQA |
| Flight origin | London Heathrow Airport |
| Stopover | Singapore Changi Airport |
| Destination | Sydney Airport |
Qantas Flight 32 was a Qantas passenger flight that on 4 November 2010 suffered an uncontained engine failure and was forced to make an emergency landing at Singapore Changi Airport. The failure was the first of its kind for the four-engined Airbus A380, the world's largest passenger aircraft. On inspection, it was found that the aircraft's No.2 engine (on the port side nearest the fuselage), a Rolls-Royce Trent 900, had a missing turbine disc. The aircraft had also suffered damage to the nacelle, wing, fuel system, landing gear, flight controls, and to the controls for engine No.1.
The involved aircraft's tail number was VH-OQA, Nancy Bird Walton, Qantas' first A380, delivered in September 2008. The failure occurred over Batam Island, Indonesia on Flight 32 from London Heathrow Airport to Sydney Airport, four minutes after taking off from Changi for the second leg of the flight. After holding to determine aircraft status, the aircraft returned to Changi nearly two hours after take-off. There were no injuries to the passengers, crew or people on the ground; debris from the accident fell onto the Indonesian island of Batam.[3]
The A380 first entered commercial service in October 2007, and at the time of the accident, a total of 39 A380s were operating with five airlines, Air France, Emirates, Lufthansa, Singapore Airlines (SIA) and Qantas. The accident led to the temporary grounding of the rest of the five-plane Qantas A380 fleet, and groundings, inspections and engine replacements on some other Rolls-Royce powered A380s in service with Lufthansa and Singapore Airlines, but not in the A380 fleets of Air France or Emirates, which are powered by Engine Alliance engines.
Contents |
The aircraft involved was an Airbus A380-842, registration number VH-OQA, serial number 014.[1][4] Delivered in September 2008, the aircraft had four Trent 972 engines manufactured by Rolls-Royce.[5] The aircraft (named Nancy Bird Walton in honour of the Australian aviation pioneer) was the first A380 delivered to Qantas.[6] Qantas expects repairs on the aircraft to be completed by February 2012 and plans to return it to service in the first half of 2012.[7]
The accident, at 10:01 am Singapore Standard Time (02:01 UTC), was caused by an uncontained failure of the port inboard (Number 2) engine, while en route over Batam Island, Indonesia.[1][8]
Shrapnel from the exploding engine punctured part of the wing and damaged the fuel system, causing leaks[9] which disabled one hydraulic system and the anti-lock brakes and caused No.1 and No.4 engines to go into a ‘degraded’ mode,[10] damaged landing flaps and the controls for the outer left No.1 engine.[11]
The crew, after finding the plane controllable, decided to fly a racetrack holding pattern close to Changi airport while assessing the status of the aircraft. It took 50 minutes to complete this initial assessment. The First Officer (FO) and Supervising Check Captain (SCC) then input the plane's status to the landing distance performance application (LDPA) for a landing 50 tonnes over maximum landing weight at Changi.[10] Based on these inputs the LDPA could not calculate a landing distance. After discussion the crew elected to remove inputs related to a wet runway, in the knowledge that the runway was dry. The LDPA then returned the information that the landing was feasible with 100 metres of runway remaining.[12] The flight then returned to Singapore Changi Airport, landing safely after the crew extended the landing gear by a gravity drop emergency extension system,[12][9] at 11:45 am Singapore time.[13][14] As a result of the aircraft landing 35 knots faster[10] than normal, four tyres were blown.[15]
Upon landing, the crew were unable to shut down the No.1 engine, which had to be doused by emergency crews 3 hours after landing until flameout.[12][16] The pilots considered whether to evacuate the plane immediately after landing as fuel was leaking from the left wing onto the brakes, which were extremely hot from maximum braking. The SCC pilot, David Evans, noted in an interview, "We’ve got a situation where there is fuel, hot brakes and an engine that we can’t shut down. And really the safest place was on-board the aircraft until such time as things changed. So we had the cabin crew with an alert phase the whole time through ready to evacuate, open doors, inflate slides at any moment. As time went by, that danger abated and, thankfully, we were lucky enough to get everybody off very calmly and very methodically through one set of stairs."[10] The plane was on battery power and had to contend with only one VHF radio to coordinate emergency procedure with the local fire crew.[17]
There were no injuries reported among the 440 passengers and 29 crew on board the plane.[18] Debris also fell on a school and houses, causing structural damage,[19] and on a car.[20]
The pilot of the plane, Captain Richard Champion de Crespigny, has been credited in the media as "having guided a heavily damaged double-decker jet to the safety of Singapore Airport and averting what could have been a catastrophe".[21] He has 35 years of flying experience and was the first Qantas "line" pilot to fly the Airbus A380.[22]
On 18 November Richard Woodward, a vice president of the Australian and International Pilots Association reported that there were five pilots on the cockpit of this flight. In addition to the normal crew of Captain, First and Second Officer, there were two additional check captains. The captain who was being trained as a Check Captain (CC) and the Supervising Check Captain (SCC) who was training the CC.[12] Captain de Crespigny concentrated on flying and managing the aircraft and monitoring the (57 ECAM) checklists being actioned by the First Officer. The supernumerary pilots monitored all actions and assisted where necessary.[23]
The ongoing investigation by the Australian Transport Safety Bureau indicated that "fatigue cracking" in a stub pipe within the engine resulted in oil leakage followed by an oil fire in the engine.[24] The fire led to the release of the Intermediate Pressure Turbine (IPT) disc. It also said the issue is specific to the Trent 900.[25]
Rolls Royce determined that the direct cause of the oil fire and resulting engine failure was a misaligned counter bore within a stub oil pipe leading to a fatigue fracture.[26] The ATSB's preliminary investigation report confirmed that Rolls Royce determination.[12]
Airbus determined that the IPT disc released three different high energy fragments, resulting in structural and systems damage. It also concluded that segregated wiring routes were cut by two out of the three individual pieces of disc debris and as a result, engine one could not be shut down after landing.[27]
On 10 November, the European Aviation Safety Agency issued an Emergency Airworthiness Directive, ordering airlines using the Trent 900 engine to conduct frequent and stringent tests, including extended ground idle runs, Low Pressure Turbine (LPT) stage one blade and case drain inspections and High Pressure/Intermediate Pressure (HP/IP) structure air buffer cavity and oil service tube inspections.[28] However, on 22 November, the EASA eased its inspection guidelines, citing progress in the investigation. It dropped requirements for extended ground idle runs and requirements for repetitive inspections of the LPT stage one blades and case drain.[29] On 2 December, the ATSB ordered a one-off inspection of the "relevant" Trent 900 engines within two flight cycles.[24]
On 3 December, the ATSB issued a preliminary report which contained a key finding of a manufacturing flaw: An area of fatigue cracking was found within a stub pipe, that feeds oil to the engine HP/IP bearing structure.[12] Bearing lubricating oil leaked from that crack, causing the subsequent engine fire and failure of the IP turbine disc. The fatigue fracture was a result of the misalignment of that stub pipe, during the counter-boring process. That inaccurate alignment resulted in one side of the same stub pipe becoming too thin to resist fatigue fracturing.[12][30] This "could lead to an elevated risk of fatigue crack initiation and growth, oil leakage and potential catastrophic engine failure from a resulting oil fire," according to the agency.[30]
The findings were determined to be a "critical safety issue," and the ATSB recommended immediate inspections of in-service Trent 900 engines.[30] On 8 December the ATSB reported that 45 Trent 900 engines had been inspected, and 3 of these engines had failed inspection and had been removed from service.[31] On 18 May 2011, the ATSB released an interim factual report[32] which states that 53 Trent 900 engines were removed from service - 11 due to out-of-tolerance oil-feed stub pipes and 42 due to lack of measurement records relating to the oil-feed stub pipe.
Immediately after the accident, shares in the engine's manufacturer, London Stock Exchange listed Rolls-Royce plc, fell 5.5% to 618.5 pence, their sharpest fall in 18 months.[33] This was the lowest price since mid September 2010. The fall in the share price was directly attributed to this accident.[33] Shares in the European Aeronautic Defence and Space Company (EADS), which owns Airbus, also fell.[34]
By mid-morning on 8 November 2010, Rolls-Royce shares had fallen by more than 10% since the accident on the previous Thursday.[35]
Both Qantas[14][36] and SIA,[37] which uses the same Rolls Royce engine in its A380 aircraft, temporarily grounded their A380 fleets after the accident and performed further inspections. Singapore Airlines resumed operations the following day.[37]
Investigation of all four other operational Qantas A380s revealed concerns with two engines. Those engines were to be replaced, after which operation was expected to be resumed. The problems with one of these engines "could have potentially led to a repeat of Thursday's incident on QF32".[16] On 8 November 2010 the CEO of Qantas, Alan Joyce, stated that the A380 fleet would remain grounded because new issues in the engines appeared,[38] including oil leaks within the engines, something Joyce said was "beyond normal tolerances".[39] Singapore Airlines, which initially stated it "did not find any issues of concern"[40] after inspecting the engines of its A380s, announced on November 10 it planned to replace three engines on three separate planes, grounding the aircraft in question until the issues were resolved.[41] The airline allowed the planes to return to Singapore after discovery of the anomaly.[41] On November 10, Lufthansa announced the replacement of an engine on its first A380 which it termed "precautionary".[42] On 3 December, Qantas announced that a total of 16 Trent 900 engines needed to have repairs made or be replaced entirely; at the time of the announcement, the airline said five had already been replaced.[43]
On 23 November, Qantas announced that it would begin to partially return its fleet of A380s to service, beginning on 27 November.[44] Initially two of its six A380s were taken into use while the rest of the fleet stayed grounded pending inspections and engine changes.[45] The two aircraft entered service on the Sydney–Singapore–London route, where the engines use less than maximum thrust.[44] Qantas initially said it planned to refrain from using the aircraft on routes between Los Angeles and Australia, the longest routes globally served by the A380, where highest engine performance was required on take-off.[44] However, on 11 January 2011, Qantas announced it would resume using the A380 on the Los Angeles routes after talks with the manufacturers and regulators indicated the aircraft was safe to use.[46] By the end of January, Qantas operated all but one of its A380s, but did not have a timeframe for returning VH-OQA, the aircraft damaged in the accident, to service.
Tom Ballantyne, a writer on Orient Aviation Magazine, described the accident as "certainly the most serious incident that the A380 has experienced since it entered operations", and concerns have been voiced that this accident may be due to a "major problem", rather than being maintenance-related.[34] Qantas CEO Alan Joyce stated on 5 November that Qantas considered the likely cause "some kind of material failure or a design issue".[47]
The damage, described in the Sydney Morning Herald as "potentially life-threatening and extremely rare", caused aircraft engineer Peter Marosszeky, from the University of New South Wales to state that "I rarely ever see a failure like this on any engine", while Paul Cousins, the federal president of the Australian Licensed Aircraft Engineers Association stated that "fewer than 5% of engine failures involved debris leaving the casing of the engine", as was the case in this accident.[48]
This Airbus A380 accident followed two previous incidents involving Rolls-Royce Trent 900 engines. In September 2009, an engine malfunctioned on a Singapore Airlines flight from Paris to the Far East, and a Tokyo-Frankfurt Lufthansa flight in August 2010 had engine trouble which resulted in one engine being shut down due to low oil pressure. No such incidents have been reported for the Airbus A380s that are powered by Engine Alliance engines (made by GE Aircraft Engines and Pratt & Whitney as a joint venture) and operated by Emirates and Air France.[49]
An airworthiness directive was issued by the European Aviation Safety Agency on 4 August 2010 that required inspection of certain aspects of the Rolls-Royce Trent 900 engine.[47]
On 22 June 2011 Qantas announced that it had agreed to compensation from Rolls-Royce to a figure of approximately US$100 million.[50] Repairs to the A380 involved will cost around $135 million and is covered by insurance, with the aircraft expected to return to service in February 2012.[51]