New Delhi: The fuel supply to the engines of the Air India jet that crashed last month was cut off almost immediately after takeoff, causing the plane to plummet back to the ground after pilots failed to regain thrust in time to avert the catastrophe, a preliminary report has found.

The London-bound Boeing 787-8 Dreamliner crashed shortly after taking off from Ahmedabad airport in the western Indian state of Gujarat on June 12.

The Air India flight was carrying 242 people — 230 passengers, two pilots and 10 crew members. Only one person, a British national sitting in an emergency exit seat, survived the crash, which also killed 19 people on the ground.

On Saturday, India’s Aircraft Accident Investigation Bureau issued the first report of the deadly incident, revealing that the flight lasted about 30 seconds between takeoff and crash.

Once the aircraft achieved its maximum recorded speed, “the Engine 1 and Engine 2 fuel cutoff switches transitioned from RUN to CUTOFF position one after another” within a second, according to a chronology laid out in the report, meaning that the fuel supply to the engines was stopped.

It also indicated confusion in the cockpit moments before the crash, as “one of the pilots is heard asking the other why did he cutoff” in the cockpit voice recording, while “the other pilot responded that he did not do so.”

About 10 seconds after the fuel cut-off, the switches were moved back in quick succession to their so-called run position. The pilots managed to relight both engines, but only one of them properly engaged, while the other failed to build up enough power again.

One of the pilots issued a “mayday, mayday, mayday” distress call just a few seconds before impact. But before air traffic controllers could get a response about what had gone wrong, the plane crashed just outside the airport boundary and then plunged into a hostel packed with medical students.

The commanding pilot of the Air India plane was Sumeet Sabharwal, 56, who had a total flying experience of 15,638 hours. His co-pilot was Clive Kunder, 32, who had 3,403 hours of total experience.

AAIB’s preliminary report did not provide a full picture of the interaction between the two pilots in the flight deck, and there was no mention of other exchanges beyond the brief query about the switches and no specifics on each pilots’ actions.

It also included other factors that could have impacted the flight. There was “no significant bird activity” observed on the flight path and the aircraft was not carrying any dangerous goods and was taking off “within allowable limits.”

Bahadur Chand Gupta, an Indian aviation engineer, said that the fuel switch indicated a “very strange” situation in the cockpit.

“The fuel switches are guarded (by brackets) actually. Why will anybody remove them?” Gupta said. “More investigation is required … We have to find out why it happened.”

The report is based on an examination of data extracted from the cockpit voice recorder and digital flight data recorder and other details gathered from the scene of the crash, the worst aviation accident in more than a decade.

“Investigation is continuing and the investigation team will review and examine additional evidence, records and information that is being sought from the stakeholders,” AAIB said.

A final report is expected within a year.

The Airline Pilots’ Association of India said that “qualified, experienced personnel — especially line pilots — are still not being included in the investigation,” and called on the AAIB to include it, at least as observers.

ALPA India also asked for clarity on an information bulletin issued by the US’ Federal Aviation Administration about the potential disengagement of the fuel control switch locking feature.

“The report refers to a serviceability bulletin concerning the fuel control switch gates, which indicates a potential equipment malfunction,” ALPA India President Capt. Sam Thomas said in a statement.

“While the bulletin exists, ALPA-I demands clarity on whether the recommendations outlined in the bulletin were implemented prior to the flight.”