Seconds before Mayday, Air India fuel switches turned back from 'cutoff' to 'run'

While the first engine's core deceleration stopped, reversed, and began to recover, the second engine could not arrest its deceleration, according to the Aircraft Accident Investigation Bureau's report released today, a month after the June 12 crash.

In Short

• Fuel control switches moved from 'run' to 'cutoff' seconds after takeoff
• Pilots confused about who cut off the fuel, as per cockpit recording
• Both engines lost thrust; Engine 1 showed temporary recovery, Engine 2 failed

Thirteen seconds before Air Traffic Control received the “MAYDAY” call from the Ahmedabad-London AI171 Dreamliner on the day of the crash, June 12, a preliminary probe by the Civil Aviation Ministry revealed that the fuel control switches were being transitioned back from “CUTOFF” (fuel stopped) to “RUN” (fuel flowing).

Within seconds of takeoff, both engine fuel control switches were moved from “RUN” to “CUTOFF,” one after the other, with only a one-second gap. This prompted one pilot to ask, “Why did you cut off the fuel?” — to which the other replied, “I did not do so.” The cockpit recording revealed the conversation between the two pilots following the unusual action. The fuel control switches are not designed to be moved accidentally, drawing attention to their role in the accident.

According to the Aircraft Accident Investigation Bureau (AAIB), both engines of the ill-fated aircraft experienced a momentary recovery after an initial loss of thrust, but ultimately failed to stabilise even after the switches were moved back to "RUN." The crash ultimately led to the deaths of 260 people.

While the first engine’s core deceleration stopped, reversed, and began to recover, the second engine could not arrest its deceleration, according to the AAIB’s report released today, a month after the crash.

According to the recording from the Enhanced Airborne Flight Recorder (EAFR) accessed by AAIB, the Civil Aviation Ministry's investigative arm revealed that the fuel cutoff switch of the first engine transitioned from "CUTOFF" to "RUN" at about 08:08:52 UTC.

Two seconds later, the Auxiliary Power Unit (APU) inlet door began to open during takeoff, which could disrupt airflow, according to several experts. The APU provides electrical and pneumatic power while the aircraft is on the ground, and occasionally in the air.

After two seconds, the Engine 2 fuel cutoff switch also transitioned from "CUTOFF" to "RUN."

Engine 1’s core deceleration stopped, reversed and started to progress to recovery, according to the preliminary probe report.

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 report further stated.

- Ends