AI171 crash: Both fuel switches moved to cutoff just after takeoff

AAIB's preliminary probe finds cockpit confusion and sudden loss of thrust as fuel switches moved to cutoff seconds after takeoff from Ahmedabad airport on June 12

Both engine fuel switches on the Air India Boeing 787 plane that crashed in Ahmedabad last month moved to the CUTOFF position seconds after take-off, causing a sudden loss of thrust and subsequent disaster, revealed a preliminary investigation report released by the Aircraft Accident Investigation Bureau (AAIB) during the early hours of Saturday.

 

According to flight data, the switches on both engines moved from “RUN” to “CUTOFF” just three seconds after the aircraft lifted off from runway 23 of the Ahmedabad airport on June 12. The two movements of switches occurred one second apart. 

 

The cockpit voice recorder captured one pilot asking the other why the fuel was cut off, to which the other replied that he had not done it. A Mayday call was made seconds later before the aircraft crashed into the BJ Medical College hostel compound, killing 241 people on board and 19 people on the ground. 

   

One passenger miraculously survived the crash.

 

 

The AAIB report said, “The Engine 1 and Engine 2 fuel cutoff switches transitioned from RUN to CUTOFF position one after another with a time gap of one second… One of the pilots is heard asking the other why did he cutoff. The other pilot responded that he did not do so.”

 

The investigators added that the movement of both switches occurred "immediately after liftoff," when the aircraft had just reached its maximum recorded airspeed of 180 knots (about 334 km per hour).

 

While the cause of the cutoff remains undetermined, the AAIB pointed to a 2018 bulletin by the US aviation regulator Federal Aviation Administration warning of possible disengagement of fuel switch locking mechanisms on some Boeing aircraft.

 

Though the bulletin focused on the 737 model, it noted that the same switch design -- part number 4TL837-3D -- is also used on the Boeing 787. The FAA did not classify the issue as unsafe or mandate corrective action, and Air India said it did not carry out inspections as the bulletin was advisory.

 

 

The report stated that “as per the information from Air India, the suggested inspections were not carried out as the SAIB was advisory and not mandatory”.

 

It also confirmed that “there has been no defect reported pertaining to the fuel control switch since 2023 on VT-ANB (registration number of crashed plane)”.

 

“At this stage of investigation, there are no recommended actions to B787-8 and/or GE GEnx-1B engine operators and manufacturers,” it added.

 

Maintenance records showed the throttle control module on the VT-ANB aircraft had been replaced in 2019 and 2023, but not for issues related to the fuel switches. No related defects were reported since.

 

The aircraft, operating flight AI171 to London Gatwick, had achieved take-off speed and deployed its Ram Air Turbine (RAT) -- an emergency power source -- shortly after losing thrust. The crew attempted to restore power by returning both switches to RUN. Engine 1 showed signs of recovery, but Engine 2 failed to stabilise.

 

“The EGT (exhaust gas temperature) was observed to be rising for both engines indicating relight,” the report said. However, Engine 2 “could not arrest core speed deceleration and re-introduced fuel repeatedly”.

 

 

Weather conditions were normal, and the aircraft’s weight was within limits. Data from the forward flight recorder was recovered and analysed, but the rear unit was too damaged to yield usable information.

 

A former aircraft accident investigator said that fuel switches on Boeing 787s are meant to be manually operated and cannot shift to CUTOFF on their own under normal or even most abnormal scenarios.

 

“The Electronic Engine Control (EEC) can command a shutdown by cutting fuel internally, but it does not move the physical switch. If the switches actually moved

 

to CUTOFF without pilot input, that’s a serious anomaly. It’s not part of any documented automatic protection logic in the aircraft,” the investigator explained.

 

The expert suggested the cause could be a rare electrical or mechanical fault in the switch module -- such as moisture ingress, short circuit, or internal failure -- but ruled out deliberate software-driven action.

 

A second former investigator echoed this view, noting that the fuel control switches on the Boeing 787 are not motorised or electrically actuated.

 

“They are designed to remain in the position set by the pilot unless physically moved by hand,” the expert said.

 

 

 

If both switches were observed to physically move to the CUTOFF position without any crew input, it could point to a serious anomaly in the cockpit interface hardware (such as a faulty switch or wiring issue) or a transient fault in the aircraft’s avionics systems (like a brief power or voltage fluctuation).

 

“It suggests there may have been a hardware malfunction… To determine the root cause, it’s critical that investigators carry out a thorough analysis of the aircraft’s Central Maintenance Computer and related electronic logs,” the second expert added.

 

Sanjiv Kapoor, a former chief strategy and commercial officer of Vistara, said on the report’s scope in a post on X. “Important to understand no blame has been assigned, and no one has been given a clean chit. The preliminary report says what happened. How & why it happened is not in the report. The final report will have that if a cause can be established, and that can take months or years.”

 

Boeing also issued a statement. “Our thoughts remain with the loved ones of the passengers and crew on board Air India Flight 171, as well as everyone affected on the ground in Ahmedabad. We continue to support the investigation and our customer.” 

 

It added, “We will defer to the AAIB to provide information about AI171, in adherence with the United Nations International Civil Aviation Organization protocol known as Annex 13.”

 

An Air India spokesperson said, “Air India stands in solidarity with the families and those affected by the AI171 accident. We continue to mourn the loss and are fully committed to providing support during this difficult time.” 

 

The airline said it had acknowledged receipt of the AAIB’s preliminary report, and added, “Air India is working closely with stakeholders, including regulators. We continue to fully cooperate with the AAIB and other authorities as their investigation progresses. Given the active nature of the investigation, we are unable to comment on specific details and refer all such enquiries to the AAIB.”