British Airways Flight 38

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**British Airways Flight 38**
Summary
G-YMMM after the crash.
Date	January 17, 2008
Type	Landed short of runway
Site	London Heathrow Airport, United Kingdom
Passengers	136
Crew	16
Injuries	9 ^[1]
Fatalities	0
Survivors	152 (all)
Aircraft type	Boeing 777-236ER
Operator	British Airways
Tail number	G-YMMM
Flight origin	Beijing Capital International Airport, People's Republic of China
Destination	London Heathrow Airport, United Kingdom

British Airways Flight 38 (call sign Speedbird 38) was a scheduled flight from Beijing Capital International Airport which crash landed just short of the runway at its destination, Heathrow Airport, London, on 17 January 2008 after an 8100 kilometre (4400 nm) flight. There were no fatalities, but nine people sustained injuries. It was the first accident that resulted in a Boeing 777 hull loss.^[2]

1 Accident
2 Speculation
3 Initial response
4 Disruption
5 Investigation
6 See also
7 References
8 External links

[edit] Accident

The Boeing 777-236ER aircraft G-YMMM (manufacturer's serial number 30314, line number 342) repeatedly failed to respond to a demand for increased thrust from both autothrottle and from manual intervention at 720 feet (220 m) and 2 miles (3.2 km) from touchdown. In attempting to maintain the instrument landing system (ILS) glide slope, the autopilot sacrificed speed, reducing airspeed to 108 knots at 200 feet (61 m). The autopilot disconnected at 175 feet (53 m) and the aircraft landed on the grass approximately 1,000 feet (300 m) short of runway 27L. During the impact and short ground roll, the nose gear collapsed, the right main gear separated from the aircraft penetrating the central fuel tank and cabin space, and the left main gear was pushed up through the wing. The aircraft came to rest on the threshold markings at the start of the runway. A significant amount of fuel leaked, but there was no fire. The plane passed approximately 6 metres (20 ft) above passing cars on the A30 and the airport Southern Perimeter road, including the car of the Prime Minister of the United Kingdom, Gordon Brown. ^[1]^[3] Four crew members and eight passengers were taken to hospital. Eight people received minor injuries, and one passenger received a serious injury - concussion and a broken leg. ^[1]^[4]^[5]

Captain Peter Burkill said at a press conference that he would not be publicly commenting on the cause of the incident whilst the Air Accident Investigation Branch (AAIB) investigation was in progress. He revealed that Senior First Officer John Coward was flying the aircraft at the time, and that another First Officer was also present. He was later named as Conor Magenis. ^[6]

John Coward was more forthcoming in a later interview, stating -

"As the final approach started I became aware that there was no power."

"Suddenly there was nothing from any of the engines, and the plane started to glide." ^[7]

The 150-tonne aircraft was the first Boeing 777 to be written off in the model's 12 year history. ^[2]^[8]^[9]^[10]

[edit] Speculation

Initial theories about the cause have focused on a few areas. Although both engines failed to produce increased power when demanded, mechanical engine failure was not regarded as a likely cause, given the very low probability of a simultaneous dual engine failure and was ruled out by the findings of the February Special Bulletin.

One prominent theory has been a failure of the software or electronics that controls the engines. A story in The Guardian newspaper on Saturday 19 January quotes an unnamed source as stating that the Engine Pressure Ratio gauge had failed, and that an automated alarm that should have alerted the pilots to the drop in engine power failed to go off. ^[11] A failure in the electronic system of the 777 aircraft has been put forward as a probable culprit of the accident. According to a news report, an electronic glitch in the computerised engine-control systems may have disrupted the connection between automated and manual controls and the two jet engines. ^[12] But again this was ruled out by the findings of the Special Bulletin. Speculation that radio interference from the Prime Minister's motorcade was responsible for the accident was also eliminated as a cause. ^[13]

A second area of speculation centers on the fuel supply. If the cause is fuel starvation, fuel was available but could not reach the engines. Water or debris in the fuel tanks could have cut off the engines from their supply, resulting in power loss. It is unclear, however, whether a fuel supply issue would have produced simultaneous engine failures or more likely would have produced symptoms in one engine before the other. ^[12] However, according to the 24 January update, the engines lost power eight seconds apart-- the right engine approximately three seconds after more power was requested, and eight seconds later the left engine lost power. Accumulation of ice in the fuel tanks, clogging fuel supply lines in the final stages of the flight, was the subject of closer scrutiny, ^[14] until also ruled out. Both engines were still producing above-idle but significantly diminished thrust, according to a report. ^[8]

Some sources indicate that the crew declared an emergency to the control tower before landing. ^[15] David Learmount of Flight International speculated that to land in just 350-400 metres, the aircraft must have been near stalling when it touched down. Dr Thurai Rahulan and Dr Guy Gratton, both academics, speculated that the weather conditions made wind shear a possible cause. ^[4]^[16]^[17]^[18] The METAR in force at the time indicated that the wind was forecast to gust according to ICAO criteria for wind reporting, but was not gusting at the time and wind shear had not been reported. ^[19] The possibility of a bird strike was raised, but there were no sightings or radar reports of birds. ^[12] Consequently, speculation had focused on electronics and fuel supply issues. ^[20] In response to speculation that the cause of the accident was ice in the centre fuel tank, United Airlines and American Airlines took precautionary steps to ensure the quality of the fuel used in their aircraft, ^[21] but icing was later ruled out.

[edit] Initial response

Statements were issued by several organisations affiliated with the airport and airline. Immediately after the crash British Airways released this statement:

"A British Airways Boeing 777 aircraft has been involved in an incident today at Heathrow airport. The aircraft was operating as flight BA38 from Beijing." ^[22]

Boeing 777-236ER (G-YMMD), taking off from London Heathrow Airport, a model similar to the crashed aircraft.

The London Ambulance Service stated that three fast response cars, eight ambulances and several officers were sent to the scene to assess the casualties. Those injured were taken to the nearby Hillingdon hospital. ^[23]

Soon after the crash, the Civil Aviation Authority (CAA) announced that they were aware of the incident and that the "incident will be investigated by the Air Accidents Investigation Branch of the Department for Transport and the CAA is offering assistance to all organisations involved." Initial comment from David Learmount, a Flight International analyst, was that "The aircraft had either a total or severe power loss and this occurred very late in the final approach because the pilot did not have time to tell air traffic control or passengers." ^[24]

Willie Walsh, the British Airways Chief Executive released a statement praising the actions of the "flight and cabin crew [who] did a magnificent job and safely evacuated all of the 136 passengers. The captain of the aircraft is one of our most experienced and has been flying with us for nearly 20 years. Our crew are trained to deal with these situations." ^[25] He also praised the fire, ambulance and police services.

BAA Limited:

“

Incident at Heathrow

We can confirm that flight BA38, a Boeing 777 arriving from Beijing, carried out an emergency landing at Heathrow Airport today at 12:42. Heathrow’s emergency services attended the scene and passengers were immediately evacuated and taken to a reception centre at the airport. The Air Accidents Investigation Branch is attending the scene.

Heathrow Airport’s southern runway was closed immediately after the incident but has now re-opened for take-offs only. The northern runway is operating for arriving aircraft.

Passengers flying from Heathrow today should contact their airline regarding the status of their flight. Some arriving aircraft are being diverted to other airports, this is being done on a flight by flight basis.

”

—BAA Limited , BAA Heathrow Homepage

[edit] Disruption

As a consequence of the emergency services deployment to the accident all flights were halted for a short time. When operations resumed, many long-haul outbound flights were either delayed or cancelled and all short haul flights were cancelled for the rest of the day. Some inbound flights were delayed and 24 flights were diverted to Gatwick, Luton or Stansted. ^[4] Heathrow Airport received dispensation from the Department of Transport to operate some night flights. ^[25] On the following day (18 January) a total of 113 short haul flights were cancelled due to crews and aircraft being out of position. ^[5]^[26]

[edit] Investigation

Wikinews has related news:

British Airways Flight 38 investigation focuses on fuel system

The AAIB is investigating the accident, ^[4]^[27] the results of which will be published when complete. A statement has been issued by the AAIB. The investigator in charge is Robin Tydeman. ^[28] Rolls-Royce, the engine manufacturer, will also assist in the investigation, as is the established practice for major investigations.^[25] As is usual in incidents involving U.S.-manufactured aircraft, the U.S. National Transportation Safety Board (NTSB) has offered its assistance in the investigation, as has the manufacturer, Boeing. An aircraft enthusiast took photographs of the aircraft on its approach from approximately 100 feet (30 m), and released them to the air accident investigators. ^[29] On the afternoon of January 20, 2008, the aircraft was removed from its resting place with two cranes lifting it onto wheeled platforms. ^[30]

[edit] Initial report, 18 January 2008

A map showing the location of the plane (blue dot) after landing and sliding through the field on the runway safety area - route marked in red.

The AAIB released an initial report on 18 January, which stated: ^[31]

“	Initial indications from the interviews and Flight Recorder analyses show the flight and approach to have progressed normally until the aircraft was established on late finals for Runway 27L. At approximately 600 ft and 2 miles from touch down, the Autothrottle demanded an increase in thrust from the two engines but the engines did not respond. Following further demands for increased thrust from the Autothrottle, and subsequently the flight crew moving the throttle levers, the engines similarly failed to respond. The aircraft speed reduced and the aircraft descended onto the grass short of the paved runway surface.	”
—AAIB , Accident to Boeing 777-236, G-YMMM at London Heathrow Airport on 17 January 2008 - Initial Report

[edit] Initial report update, 24 January 2008

An update was issued on 24 January:^[8]

“

As previously reported, whilst the aircraft was stabilised on an ILS approach with the autopilot engaged, the autothrust system commanded an increase in thrust from both engines. The engines both initially responded but after about 3 seconds the thrust of the right engine reduced. Some eight seconds later the thrust reduced on the left engine to a similar level. The engines did not shut down and both engines continued to produce thrust at an engine speed above flight idle, but less than the commanded thrust.

Recorded data indicates that an adequate fuel quantity was on board the aircraft and that the autothrottle and engine control commands were performing as expected prior to, and after, the reduction in thrust.

All possible scenarios that could explain the thrust reduction and continued lack of response of the engines to throttle lever inputs are being examined, in close cooperation with Boeing, Rolls Royce and British Airways. This work includes a detailed analysis and examination of the complete fuel flow path from the aircraft tanks to the engine fuel nozzles.

”

—AAIB , Accident to Boeing 777-236, G-YMMM at London Heathrow Airport on 17 January 2008 - Initial Report Update

[edit] Special Bulletin, 18 February 2008

A further update, issued on 18 February, stated that there was "no evidence of a mechanical defect or ingestion of birds or ice", that there was "no evidence of fuel contamination or unusual levels of water content" within the fuel and that the recorded data indicated that there were "no anomalies in the major aircraft systems". Some small foreign bodies, however, were detected in the fuel tanks and these were to undergo further analysis.

The report noted evidence that cavitation had taken place in both high pressure fuel pumps, which could be indicative of a restriction in the fuel supply or excessive aeration of the fuel, although the manufacturer assessed both pumps as still being able to deliver full fuel flow. The report noted the aircraft had flown through air that was unusually cold (but not exceptionally so), and concluded that the temperature had not been low enough to freeze the fuel. Tests are continuing in an attempt to replicate the damage seen in the fuel pumps and to match this to the data recorded on the flight. A comprehensive examination and analysis is to be conducted on the entire aircraft and engine fuel system including modeling fuel flows taking account of environmental and aerodynamic effects.

The report went on to note that the fire extinguisher handles had been manually deployed by the crew before the fuel shut-off switches. The fire extinguisher handles also have the effect of cutting off power to the fuel switches, meaning that the fuel may continue to flow - a potentially dangerous situation. The report restated a previous Boeing Service Bulletin giving procedural advice that fuel switches should be operated before fire handles. It went on: "This was not causal to the accident but could have had serious consequences in the event of a fire during the evacuation."

Indeed, the need to issue Safety Recommendation 2008-009, affecting all 777 airframes which had yet to incorporate the Boeing Service Bulletin (SB 777-28-0025) - as was the case with G-YMMM - was given as the main reason for issuing this special bulletin, well before the accident investigation itself was complete. ^[1]

[edit] Special Bulletin, 12 May 2008

The AAIB issued a further bulletin on 12 May 2008 which confirmed that the investigation continued to focus on fuel delivery. It stated that "The reduction in thrust on both engines was the result of a reduced fuel flow and all engine parameters after the thrust reduction were consistent with this." The report confirmed that the fuel was of good quality and had a freezing point below the coldest temperatures encountered, appearing to rule out fuel freezing as a cause. As in the aforementioned February bulletin, the report noted cavitation damage to the high pressure fuel pumps of both engines, indicative of abnormally low pressure at the pump inlets. After ruling out fuel freezing or contamination, the investigation now focuses on what caused the low pressure at the pump inlets. "Restrictions in the fuel system between the aircraft fuel tanks and each of the engine HP pumps, resulting in reduced fuel flows, is suspected." The fuel delivery system was being investigated at Boeing, and the engines at Rolls Royce in Derby.

The Bulletin specifically ruled out certain other possible causes, stating: "There is no evidence of a wake vortex encounter, a bird strike or core engine icing. There is no evidence of any anomalous behaviour of any of the aircraft or engine systems that suggests electromagnetic interference." ^[32]

[edit] British Airways internal investigation

An internal investigation into the accident was conducted by British Airways. The report revealed that the actions of the flight crew prevented a worse outcome than actually occurred. It also revealed that the emergency evacuation alarm was too quiet for some passengers to hear. This is also being investigated by the AAIB.^[33]