The preliminary report on the crash of Air India Boeing 787 Dreamliner at Ahmedabad revealed that two engines had lost power just seconds after takeoff because fuel was abruptly cut off.
India’s Aircraft Accident Investigation Bureau has released a new report that sheds light on what happened in the last moments before flight AI 171, the plane which crashed into the earth on June 12 and killed 241 onboard as well as 19 people on the ground.
Takeoff is only 30 seconds away from disaster
The AAIB reported that the aircraft had reached 180 knots of speed shortly after it left the runway.
The fuel switches were switched from “run” to “cutoff” in seconds. This starved the engines and caused a complete loss of thrust.
Cockpit recordings capture one pilot asking another, “Why cut off?” and the second pilot responding, “I did not”.
After the confusion, frantic efforts were made to restore power.
The pilots successfully relit both engines about 10 seconds after cutting off the power. There was only one fully responsive engine, and the other did not have enough power for flight.
The distress call “mayday, Mayday, Mayday” was issued only moments before the plane lost height and crashed in a densely-populated area, hitting a hostel of a medical school and exploding into flames.
Boeing and GE engines are not at fault
AAIB report states that at this time, no evidence exists to suggest a fault in the design or manufacture of Boeing 787-8 or its GE GEnx-1B engine.
The report states that “At the current stage of the investigation, no recommendations are made to engine manufacturers and operators for B787-8 engines or GE GEnx-1B engines.”
Investigating why fuel switches have been moved from the on position to the off location is the main focus of the investigation.
These switches have safety mechanisms that prevent them from being accidentally activated. The report also notes an FAA bulletin issued in 2018 which warned about the potential for accidental movement on Boeing aircraft including the 787.
Air India’s jet was not checked for .
Pilot actions and experiences are investigated by investigators
Investigators have not yet identified a technical problem, but are looking at the crew’s actions.
Captain Sumeet Sabharwal, and first officer Clive Kunder had 8,200 hours and 1,100 on the 787 respectively.
This probe will examine their background, training and sequence of events during the flight.
Bjorn Fehrm, an aerospace engineer and ex-fighter pilot, commented on the unusually long delay before the switches were returned to “run”. He said, “I wouldn’t wait for 10 seconds again to turn them on.” They would be on within seconds.
India’s deadliest aviation disaster in decades
Flight AI 171’s crash is India’s worst aviation accident in over a decade. It also marks the world’s first Boeing 787 Dreamliner with a complete hull.
Fuel was loaded onto the aircraft, which was headed for London Gatwick.
The crash on the ground claimed the lives of additional people, including one person who survived the accident.
Video footage and eyewitness accounts showed that the plane took off as normal before losing height and colliding just outside of the airport’s perimeter.
Ram Air Turbine, an emergency device which deploys when there is a total loss of power, was also activated. This confirmed the loss of thrust.
Investigation continues amid unanswered questions
AAIB’s preliminary report was based on the data of the digital flight data recorder and cockpit voice recorder as well as evidence found at the crash site.
The investigation is expected to continue over several months. Additional records, logs of maintenance, as well as possible human or mechanical factors, which could explain the cutoff, will be examined.
Boeing and GE Aerospace are not implicated in this case at this time, and all investigations have been referred to Indian authorities by the National Transportation Safety Board.
Air India hasn’t issued any detailed statements as long as the investigation continues.
The preliminary report: Key Findings
| Key Event | You can find out more about it here: |
|---|---|
| Takeoff Speed | Before the cut-off, 180 knots is reached |
| Fuel cutoff | Within 1 second, both engine switches were set to “cutoff”. |
| Pilot confusion | Cockpit Voice: “Why have you stopped?” “I did not.” |
| Engine relight attempt | After 10 second, both switches returned to “run”. |
| Engine Response | The engine that failed to gain thrust was the one with the fully lit motor. |
| Crash timeline | The aircraft is airborne between 30-32 seconds, before it crashes |
| Mayday Call | Issued just seconds before impact |
| Fatalities | 241 passengers on board and 19 on the ground |
| Type of aircraft | Boeing 787-8 Dreamliner – First Total Loss of Type |
| Current Focus | Pilot actions and possible fuel system issues could explain why fuel switches were moved from cutoff to off. |
Safety and regulation in aviation
These findings raise concerns over cockpit ergonomics, and about the possibility that switches could be accidentally moved.
The FAA Bulletin 2018 regarding the fuel switch locking mechanism is being re-examined, but regulatory actions have not yet been taken.
AAIB continues to investigate whether the accident was caused by human error, mechanical failure or a combination.
According to the preliminary report of the Air India Boeing 787 accident, the cause was a sudden and unaccounted for fuel cutoff in both engines.
As there is no proof of technical or sabotage defect, attention remains focused on cockpit actions and design of fuel control system.
Aviation experts around the world await the report’s final findings, which should answer some of the questions that remain about one of India’s worst air tragedies.
As new information becomes available, the post Air India Boeing 787 crash report: preliminary report shows exactly what happened might be updated.
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