A preliminary report on the Air India crash that killed 260 people in Ahmedabad last month says the plane's engine fuel switches were flipped off within seconds of each other, starving the engines, three seconds after take-off.
The Boeing 787 Dreamliner immediately began to lose thrust and altitude, according to the report released by Indian aviation accident investigators.
It said one pilot could be heard on the cockpit voice recorder asking the other why he cut off the fuel.
"The other pilot responded that he did not do so," the report said.
It did not identify which remarks were made by the flight's captain and which by the first officer, nor which pilot transmitted "Mayday, Mayday, Mayday" just before the crash.
The preliminary report also does not say how the switch could have flipped to the cut-off position on the June 12 London-bound flight.
US aviation safety expert John Cox said a pilot would not be able to accidentally move the fuel switches that feed the engines.
"You can't bump them and they move," he said.
Flipping the switches to the cut-off position almost immediately cuts the engines.
They are most often used to turn engines off once planes have arrived at their airport gates and in certain emergency situations such as engine fires.
The report does not indicate there was any emergency requiring an engine cut-off.
"At this stage of investigation, there are no recommended actions to Boeing 787-8 and/or GEnx-1B engine operators and manufacturers," India's Aircraft Accident Investigation Bureau said.
The agency, an office under India's civil aviation ministry, is leading the probe into the world's deadliest aviation accident in a decade.
PS: The report can be found on
https://aaib.gov.in/What's New Assets/Preliminary Report VT-ANB.pdf
Extract -
As per the EAFR, the Engine 1 fuel cutoff switch transitioned from CUTOFF to RUN at about 08:08:52 UTC. The APU Inlet Door began opening at about 08:08:54 UTC, consistent with the APU Auto Start logic. Thereafter at 08:08:56 UTC the Engine 2 fuel cutoff switch also transitions from CUTOFF to RUN. When fuel control switches are moved from CUTOFF to RUN while the aircraft is inflight, each engines full authority dual engine control (FADEC) automatically manages a relight and thrust recovery sequence of ignition and fuel introduction. The EGT was observed to be rising for both engines indicating relight. Engine 1’s core deceleration stopped, reversed and started to progress to recovery. Engine 2 was able to relight but could not arrest core speed deceleration and re-introduced fuel repeatedly to increase core speed acceleration and recovery. The EAFR recording stopped at 08:09:11 UTC At about 08:09:05 UTC, one of the pilots transmitted “MAYDAY MAYDAY MAYDAY”. The ATCO enquired about the call sign. ATCO did not get any response but observed the aircraft crashing outside the airport boundary and activated the emergency response.
The Boeing 787 Dreamliner immediately began to lose thrust and altitude, according to the report released by Indian aviation accident investigators.
It said one pilot could be heard on the cockpit voice recorder asking the other why he cut off the fuel.
"The other pilot responded that he did not do so," the report said.
It did not identify which remarks were made by the flight's captain and which by the first officer, nor which pilot transmitted "Mayday, Mayday, Mayday" just before the crash.
The preliminary report also does not say how the switch could have flipped to the cut-off position on the June 12 London-bound flight.
US aviation safety expert John Cox said a pilot would not be able to accidentally move the fuel switches that feed the engines.
"You can't bump them and they move," he said.
Flipping the switches to the cut-off position almost immediately cuts the engines.
They are most often used to turn engines off once planes have arrived at their airport gates and in certain emergency situations such as engine fires.
The report does not indicate there was any emergency requiring an engine cut-off.
"At this stage of investigation, there are no recommended actions to Boeing 787-8 and/or GEnx-1B engine operators and manufacturers," India's Aircraft Accident Investigation Bureau said.
The agency, an office under India's civil aviation ministry, is leading the probe into the world's deadliest aviation accident in a decade.
PS: The report can be found on
https://aaib.gov.in/What's New Assets/Preliminary Report VT-ANB.pdf
Extract -
As per the EAFR, the Engine 1 fuel cutoff switch transitioned from CUTOFF to RUN at about 08:08:52 UTC. The APU Inlet Door began opening at about 08:08:54 UTC, consistent with the APU Auto Start logic. Thereafter at 08:08:56 UTC the Engine 2 fuel cutoff switch also transitions from CUTOFF to RUN. When fuel control switches are moved from CUTOFF to RUN while the aircraft is inflight, each engines full authority dual engine control (FADEC) automatically manages a relight and thrust recovery sequence of ignition and fuel introduction. The EGT was observed to be rising for both engines indicating relight. Engine 1’s core deceleration stopped, reversed and started to progress to recovery. Engine 2 was able to relight but could not arrest core speed deceleration and re-introduced fuel repeatedly to increase core speed acceleration and recovery. The EAFR recording stopped at 08:09:11 UTC At about 08:09:05 UTC, one of the pilots transmitted “MAYDAY MAYDAY MAYDAY”. The ATCO enquired about the call sign. ATCO did not get any response but observed the aircraft crashing outside the airport boundary and activated the emergency response.
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