Fuel switches cut mid-air: Key cockpit action led to AI 171 crash, probe reveals

In a chilling revelation, India's worst aviation disaster in four decades may have been triggered by the abrupt and near-simultaneous shutdown of both engines — just moments after takeoff.

The preliminary report by the Aircraft Accident Investigation Bureau (AAIB) into the June 12 crash of Air India Flight AI 171 has zeroed in on one deeply disturbing detail: the Boeing 787-8 Dreamliner’s fuel control switches transitioned from ‘RUN’ to ‘CUTOFF’ within a second of each other, plunging the aircraft into a fatal descent shortly after it lifted off from Mumbai.

While early investigation reports are typically sparse, the 15-page AAIB document released on July 12 is unusually detailed, pointing toward a possible cockpit action rather than a mechanical or system fault.

What the cockpit recorder revealed

The aircraft was being flown by co-pilot Clive Kundar, with commander Sumeet Sabharwal as pilot monitoring. According to the cockpit voice recorder, one pilot can be heard asking the other, “Why did you cut off the fuel?”— to which the response was, “I didn’t.” The report does not identify which pilot made the comment.

Both pilots were rested, had passed routine breathalyser checks, and the aircraft had cleared all maintenance checks prior to departure. The flight began normally — until the jet reached about 400 feet altitude, when disaster struck.

A nearly impossible switch movement?

According to aviation experts and airline sources, the fuel control switches — critical components that regulate engine fuel flow — are designed to prevent accidental activation. The switches are fitted with side brackets and a stop-lock mechanism that require deliberate lifting before they can be toggled between the two positions. Their standard use is limited to starting the engine before departure and shutting it down upon arrival.

The preliminary report does not conclusively state whether a pilot toggled the switches or if a rare malfunction occurred. But investigators recovered the switches from the wreckage in the RUN position, suggesting they may have been returned there during an emergency attempt to restart the engines.

Emergency systems kicked in but too late

The report notes that the Ram Air Turbine (RAT) and the Auxiliary Power Unit (APU) — both emergency backup power sources — activated immediately after the engines failed. Their deployment confirms that both primary engines had shut down mid-air, triggering automatic power safeguards.

The RAT, a small turbine deployed into the airstream, generates emergency power when all main systems fail. The APU, a secondary turbine in the aircraft’s tail, automatically starts when engine power is lost.

FAA warning ignored but not binding

Interestingly, the report references a 2018 FAA bulletin on potential disengagement of the fuel switch locking mechanism in Boeing 737s — which share design elements with the 787’s control module. However, Air India did not inspect the system, as the bulletin was advisory, not mandatory.

Maintenance logs show the cockpit throttle module, which houses these switches, was replaced in 2019 and 2023, though no fuel switch-related faults were reported. The AAIB also confirmed that all Airworthiness Directives and Service Bulletins had been complied with.

No fault found in aircraft or engine — focus shifts to cockpit action

At this stage, the AAIB has not issued any safety recommendations to Boeing 787-8 operators or the GE GEnx-1B engine manufacturer — a strong indicator that investigators do not suspect technical or mechanical failure.

The probe is now centered on pilot action or possible human error. While the final report is expected within a year, officials say it could be released earlier, given the depth of preliminary findings.

Aviation’s black box of unanswered questions

The AI 171 crash has left behind a trail of unnerving questions: Who triggered the switches? Why? Could it have been a mechanical anomaly or a human lapse? While the answers remain pending, what’s clear is this — two critical switches moved at the worst possible moment, and with them, 231 lives were lost in India’s deadliest aviation tragedy since 1985.