Fuel Cutoff Mystery Deepens: AAIB's Preliminary Report Unpacks Air India AI171 Crash

The Aircraft Accident Investigation Bureau (AAIB) has released its preliminary findings into the catastrophic crash of Air India Flight AI171, a Boeing 787-8 Dreamliner, which occurred on 12 June 2025 shortly after takeoff from Ahmedabad. The tragedy claimed 260 lives and marked the first fatal hull loss of a Dreamliner globally.

Key Developments from the AAIB Report:

1. Flight Timeline and Engine Behavior
   - The aircraft reached a maximum speed of 180 knots IAS seconds after liftoff.
   - Immediately following this, both Engine 1 and Engine 2 fuel cutoff switches transitioned from RUN to CUTOFF within one second of each other.
   - Engine N2 values dropped below minimum idle speed, indicating a complete loss of thrust.
   - EGT (Exhaust Gas Temperature) readings began rising, suggesting attempted engine relight.
   - Both fuel cutoff switches were later toggled back to RUN, but the aircraft was already at critically low altitude.

2. Cockpit Voice Recorder Revelations
   - One pilot is heard asking the other, “Why did you cutoff?” to which the response was, “I didn’t.”
   - This exchange has raised questions about possible inadvertent switch activation or system malfunction.

3. Flight Data Recorder Status
   - The forward Enhanced Airborne Flight Recorder (EAFR) was successfully accessed.
   - The aft EAFR was substantially damaged and could not be downloaded through conventional means.

4. Fuel Quality and Contamination Checks
   - Fuel samples from bowsers and tanks used for refueling were tested at DGCA’s lab and found satisfactory.
   - Limited fuel samples retrieved from the aircraft itself are undergoing further testing.

5. Maintenance and Airworthiness
   - All Airworthiness Directives and Service Bulletins had been complied with.
   - The aircraft had active MELs (Minimum Equipment List items), none of which were linked to engine control systems.
   - A prior FAA advisory from 2018 warned of potential disengagement of fuel switch locking mechanisms, but Air India did not act on it as it was non-mandatory.

6. Human Factors and Medical Analysis
   - Postmortem reports of crew and passengers are being analyzed to correlate aeromedical findings with engineering data.
   - Both pilots had sufficient rest and experience on the aircraft type.

7. Wreckage and Investigation Status
   - Engines and key components have been quarantined for further examination.
   - Drone-based imaging and debris mapping have been completed.
   - Statements from eyewitnesses and the lone survivor have been recorded.

8. Air India’s Response
   - Air India has acknowledged receipt of the AAIB’s preliminary report.
   - The airline reiterated its full cooperation with investigative authorities.

Next Steps:
The AAIB has not issued any immediate safety recommendations for Boeing or GE. The investigation continues, with deeper analysis expected in the final report due within a year.

Sources: CNBC-TV18, The Hindu, Indian Express, Moneycontrol, Deccan Herald, Firstpost, AAIB Preliminary Report Document