Air India: The Mysterious 10-Second Fuel Cut

The fuel supply to the Boeing 787's engines was interrupted for only 10 seconds. However, it was those fateful 10 seconds that led to the Air India plane crash on June 12, killing 260 people.

According to the preliminary report released by the Indian Aviation Accident Investigation Bureau on Friday, the cut occurred after the switches were activated by one of the pilots, as the aircraft's recording system captured one of the pilots asking the other why he cut the fuel and the other responding that he did not.

These switches are typically used when the aircraft is on the ground, first to start the engines before flight and then to turn them off.

According to the document, the plane was authorized to take off at 08:07:33 on runway 23. It reached a maximum speed of 180 knots (equivalent to approximately 333 kilometers/hour) at 08:08:42 (UTC time) and, “immediately thereafter, the fuel cutoff switches for Engine 1 and Engine 2 went from the RUN position to the CUTOFF position, one after the other, with an interval of 01 second”.

Following this action, engine power immediately began to decline, and the aircraft "began to lose altitude before crossing the airport perimeter wall," eventually crashing near a complex of five buildings belonging to the Byramjee Jeejeebhoy Medical College residence in Ahmedabad. It had just departed from Sardar Vallabhbhai Patel International Airport bound for London Gatwick Airport.

With no significant bird activity reported in the airspace covered by the Boeing 787, both engines' throttle values dropped below minimum idle speed and the Ram Air Turbine (RAT) hydraulic pump — a system that generates power from air currents and is normally only activated in an emergency — began providing power at 08:08:47.

That is, just five seconds after maximum speed and the fuel cut-off switch has been activated.

According to data stored by the aircraft's black box, the fuel cutoff switch for Engine 1 went from CUTOFF to RUN at approximately 08:08:52, completing the 10-second cycle without fuel supply.

Two seconds later, at 08:08:54, the auxiliary power unit (APU) inlet door began to open, following an automatic start logic, and at 08:08:56 the fuel cut-off switch of the second engine also changed, going from CUTOFF to RUN.

“When the fuel control switches are moved from CUTOFF to RUN while the aircraft is in flight, each full-authority dual-control engine automatically generates a relight and recovery sequence of ignition pulse and fuel introduction,” the report describes.

The document states that the exhaust gas temperature sensor was rising on both engines, confirming the restart procedure. At the same time, engine 1 began to recover from the deceleration it had suffered due to the fuel cutoff, while engine 2 restarted, "but was unable to stop the core speed deceleration and repeatedly reintroduced fuel to increase acceleration and speed recovery."

Just nine seconds after the second engine was re-ignited, one of the pilots issued the international distress message at 08:09:05 — “Mayday, Mayday, Mayday.”

Air traffic control reportedly asked the plane's pilots about the alert, but received no response. At 8:09:11, six seconds after the alert message, the audio and data recording system (black box) stopped working.

The plane had crashed outside the airport, killing 241 people on board (12 crew members and 229 passengers) and 19 on the ground. Among those on board, only one survivor was recorded.

The possible human error behind the Air India plane crash, foreshadowed by the Indian authorities' preliminary report, is sparking outrage among Indian pilots, who criticize the document's intent, which fails to address questions about possible technical failures.

The report notes that the aircraft's maintenance was up to date, but also recalls a 2018 FAA bulletin regarding the potential unlocking of the Boeing 737's fuel control switch, in which these devices were installed "with the lockout function disengaged." However, "the airworthiness concern was not considered an unsafe condition that warranted a directive" from the federal agency.

"The tone and direction of the investigation suggest a bias toward pilot error," Captain Sam Thomas, president of the Indian Pilots Association (ALPA), was quoted as saying by the Hindustan Times , adding: "ALPA India categorically rejects this presumption and insists on a fair and fact-based inquiry. We also renew our request to be included—at least as observers—in the investigation process to ensure transparency and accountability."

Records indicate that both pilots were experienced and accustomed to that Boeing model: one of the pilots was 56 years old and had more than 15,000 flight hours (of which more than 8,500 in that type of aircraft), while the other, 32 years old, had already accumulated more than 3,400 flight hours (more than 1,000 in that type of aircraft).

In turn, India's Civil Aviation Minister, Kinjarapu Naidu, quoted by Sky News , sought to ease the tensions that had begun to arise with the report and praised Indian pilots. "We are concerned about the welfare and well-being of pilots, so we will not jump to conclusions at this stage; we will wait for the final report. I believe we have the best pilot and crew workforce in the world," he declared.