The Federation of Indian Pilots (FIP) on Sunday, 14 June formally urged the Aircraft Accident Investigation Bureau (AAIB) to conduct a new, comprehensive series of Boeing 787 simulator tests and re-examine evidence related to the deployment of the aircraft's Ram Air Turbine (RAT) in the crash of Air India Flight AI-171. The pilots' body argues that existing simulator data contradicts critical timestamps in the bureau's preliminary report — a discrepancy it says could fundamentally alter the understanding of what caused the disaster.

The Core Dispute: RAT Timing

At the heart of FIP's challenge is the timing of RAT power generation following a fuel system interruption. According to the AAIB's preliminary report, fuel system interruption occurred at 08:08:42 UTC, with hydraulic power from the RAT produced approximately four to five seconds later. However, FIP — citing a submission from advocate D. Michael Andrews of Beasley Allen, a US law firm representing passengers and families affected by the crash — contends that Boeing 787 simulator testing shows RAT-generated power is not produced until around 18 seconds following fuel system interruption. That is a gap of roughly 14 seconds, which FIP president Captain C.S. Randhawa described in a letter to the AAIB Director General as warranting urgent independent verification.

The submission quoted in the letter states: 'The videos and preliminary data analysis appear to contradict key points in the timeline of VT-ANB RAT deployment and power generation contained within the Indian AAIB preliminary report.' If the RAT power-generation timestamp recorded on aircraft VT-ANB is accurate and simulator tests are representative of real aircraft performance, FIP argues this would suggest the RAT had already deployed and begun spinning before any fuel interruption occurred.

What the Runway Footage Reportedly Shows

FIP's letter also draws attention to images reproduced in the AAIB preliminary report showing the RAT visible immediately after take-off. It further claims that still images extracted from Ahmedabad Airport security-camera footage appear to show the RAT already deployed on the runway before the aircraft rotated for take-off. Taken together, FIP argues these observations 'tend to indicate that the RAT deployment — a potential symptom of electrical system failure — was not caused by alleged pilot-induced fuel system changes.'

Take-Off Performance Discrepancies

The letter also flags differences between take-off performance figures in the AAIB timeline and those produced in simulator runs. The AAIB timeline recorded achievement of V1 at 56 seconds and VR at 58 seconds. Simulator testing reportedly produced a mean V1 time of 40.9 seconds across nine static take-off tests and 46 seconds in one rolling take-off test, while VR was reached at a mean of 42 seconds in static tests and 48 seconds in the rolling take-off test.

What FIP Is Asking Investigators to Do

FIP has made several specific requests to the AAIB. It is asking investigators to conduct Boeing 787 simulator tests in the presence of an FIP-nominated observer to independently verify the acceleration profile in the preliminary report and the relationship between RAT deployment, RAT hydraulic power generation, and fuel-control-switch movement. It has also requested that Air India Engineering and Boeing be directed to decode fault and status data from ACARS maintenance messages transmitted between 07:53 UTC — approximately 14 minutes before the take-off roll — and 08:09 UTC, when a mayday call was transmitted. The letter references ACARS entries covering systems including BPCU Gateway Operations, Flight Control Modules, Hydraulic Operations, General Processing Modules, and Common Core System functions.

FIP additionally requested a copy of Ahmedabad Airport security-camera footage for independent analysis, and asked investigators to examine why Air India's Flight Operations and Flight Safety departments had not flagged what it described as 'discrepancies involving RAT hydraulic-power timings and aircraft maintenance messages during the investigation.' The letter noted that FIP had previously written to investigators on 12 March and 17 March on related matters concerning simulator correlation with RAT imagery and the Digital Flight Data Recorder timeline.

Background: India's Deadliest Aviation Disaster in Decades

The crash of Air India Flight AI-171, a Boeing 787-8 operating from Ahmedabad to London Gatwick, occurred on 12 June last year. It killed 241 of the 242 people aboard and 19 people on the ground, making it one of India's deadliest aviation disasters. The AAIB has confirmed the inquiry remains ongoing, with no final report yet issued. Analysis of flight data, maintenance records, operational information, and engine examinations is continuing. The FIP's intervention signals that the investigation is entering a more contested phase, with independent technical scrutiny intensifying alongside the official inquiry.