BENGALURU – The fuel control switch went off within three seconds of take-off, leading both engines to shut down moments before the Air India Boeing 787 London-bound flight crashed in Ahmedabad, said a preliminary report by the Indian government.
The 15-page report was released by India’s Aircraft Accident Investigation Bureau (AAIB) late on July 11, detailing findings from its probe into the
plane crash on June 12 that killed 260 people
– 229 passengers, 12 crew members, and 19 individuals on the ground. Only one passenger miraculously survived.
The crux of
the preliminary report
is its revelation that “the Engine 1 and Engine 2 fuel cut-off switches transitioned from RUN to CUTOFF position one after another with a time gap of 01 second”.
In the cockpit voice recording, the report says, “one of the pilots is heard asking the other why did he cut off. The other pilot responded that he did not do so”.
Within 32 seconds of taking off, the plane had crashed into buildings just outside the Sardar Vallabhai Patel airport, including a medical college hostel.
These details were retrieved from an Enhanced Airborne Flight Recorder (EAFR), commonly known as the black box, in the forward section of the plane. The rear black box was substantially damaged, and no data could be downloaded.
The report lists damage to the aircraft parts and data from flight recorders. It does not ascertain reasons for the crash, or who is responsible for it.
The possibility of one of the pilots inadvertently hitting the off switch is remote, said Mr Hemanth DP, chief executive of the Hyderabad-based Asia Pacific Flight Training Academy.
The lock safety mechanism of “lift and twist” is built into the Boeing’s fuel controls so that pilots cannot just switch off the fuel to the engine by mistake, he explained.
“The fuel control switch cannot be turned off by mistake if the lock system was there. Even if there was an engine problem, like a fire or debris, the pilot would not switch both engines off while airborne,” he said, adding that it sounded like the pilots were surprised when they realised that the fuel switch had turned off and they switched it on again to try and prevent the crash.
“Unfortunately, they couldn’t do much in 30 seconds,” Mr Hemanth said.
Based on the preliminary report, experts are divided on whether to attribute the crash to an aircraft design flaw or human error.
The government report says the particular Boeing 787-8 aircraft had a valid airworthiness certificate from 2025.
However, it notes that the United States’ Federal Aviation Administration (FAA) issued a Special Airworthiness Information Bulletin (SAIB) on Dec 17, 2018, regarding “the potential disengagement of the fuel control switch locking feature”.
This was based on reports of operators of Boeing 737 planes in which the fuel control switches were installed with the lock disengaged.
Similar fuel switch and lock systems manufactured by Honeywell are installed in various Boeing models, including the Boeing 787-8, the type of plane that crashed in Ahmedabad.
The SAIB from 2018 warned that should the locking mechanism of the fuel switch be disengaged, it “could result in inadvertent operation that could result in unintended switch movement between the fuel supply and fuel cut-off positions”.
Usually, to move the fuel switch when the lock is engaged, “it is necessary for the pilot to lift the switch up while transitioning the switch position”, the bulletin noted.
If the locking feature is disengaged, as it was in the 737s the FAA had examined in 2018, the fuel switch could be moved from Run to Cutoff without lifting the switch, running the risk of “potential of inadvertent operation” of the switch.
“Inadvertent operation of the switch could result in an unintended consequence, such as an in-flight engine shutdown,” the SAIB said.
The FAA did not deem the issue an “unsafe condition” mandating corrective action, but recommended that all owners and operators of the affected planes check that the locking feature of the fuel control switch was engaged, and replace the switch if the lock was found to be disengaged.
ST has reached out to the FAA with queries.
The crash in Ahmedabad has renewed the long-standing concerns about Boeing’s safety lapses in manufacturing, which whistleblowers like Mr John Barnett, a former Boeing quality manager, flagged before
his mysterious death in 2024
.
Denying his accusations, Boeing said that all its aircraft were built to the highest levels of safety and quality. The company insisted that “safety, quality and integrity are at the core of Boeing’s values”.
India’s preliminary report says that Air India did not carry out the recommended inspections as “the SAIB was advisory and not mandatory”. Maintenance records of the crashed aircraft show that the throttle control module was replaced in 2019 and 2023 for reasons not linked to the fuel control switch, but the report also says there was no defect reported on the fuel control switch since 2023.
Both fuel control switches going off “is highly mysterious and needs detailed investigation, especially in light of the December 2018 FAA directive on the fuel control switches”, said Mr Sanjay Lazar, chief executive of Pune-based aviation consultation firm Avaialaz Consultants.
To know if “it could have happened mechanically or technically on its own”, the complete transcript of the cockpit voice recorder and a probe into the fuel switches are necessary, he added.
Retired airline pilot and aircraft safety adviser Captain Mohan Ranganathan told ST that if there was a serious issue in the fuel switch’s locking mechanism, the FAA would have insisted on a mandatory fix.
“That it is an advisory means they didn’t consider that it can happen,” he said.
“It can only be a deliberate human intervention that moved the fuel switch,” said Capt Ranganathan, given that both fuel switches did not have simultaneous failure, but were cut off one second apart.
“The report has not clearly identified which pilot handled the fuel selector,” he added.
Although the report refers to them as “one pilot” and “the other pilot”, Capt Ranganathan highlighted that it does say that the co-pilot was flying the aircraft, which means the senior pilot in command was monitoring the take-off check-list items, which includes the fuel selector.
A full cockpit voice recording will help identify who said what, because the pilots’ headphone mics will have been recorded on different sides, he said.
Most of the experts ST spoke with dismissed speculation of “pilot suicide” making the rounds on television channels and social media in India, saying there was no evidence behind such a conspiracy theory.
“The reported statements itself show that both pilots were unaware as to how the fuel switch had turned from ON to OFF,” Mr Lazar noted.
The preliminary report also says that “both pilots had adequate rest prior to operating this flight”, and that there was no significant bird activity to suggest a bird strike, putting paid to theories floated by experts and aviation enthusiasts soon after the fatal crash.
The flight had adequate fuel of 54,200kg, enough for its journey to London Gatwick, and the take-off weight of 213,401kg was within the allowable 218,183kg limit. There were no dangerous goods on the plane.
Investigations are ongoing, and a final report is expected within a year.
