Air India Ai 171 Crash Beasley Allen Boeing 787 Rat Simulator Timeline Dispute Aaib

The United States-based legal firm that is representing nearly 130 families of those killed in the AI 171 crash in Ahmedabad last year has submitted flight simulator tests data to aviation agencies in the US and United Kingdom stating that these do not match those related to Ram Air Turbine (RAT) deployment shared in the preliminary report released by the Aircraft Accident Investigation Bureau (AAIB) of India.

The Gatwick London-bound Boeing 787 flight had crashed seconds after take-off from Ahmedabad, killing 241 of the 242 passengers, and 19 people on the ground.

As per the AAIB preliminary report, released within a month of the crash, hydraulic power was generated by RAT “4-5 seconds” after fuel system interruption onboard AI 171. However, as per Beasley Allen Law Firm, simulator tests show that RAT deploys on a Boeing 787 only “around 18 seconds” after fuel system interruption.

In the letter to the US and UK authorities, D Michael Andrews, the principal attorney of Beasley Allen, said this means that RAT was deployed on AI 171 even before the fuel cutoff, which “is not a small mismatch but a serious technical contradiction”, and an indication that the deployment “was not caused by alleged pilot induced fuel system changes”.

RAT is Boeing 787’s back-up for hydraulic power generation, which is deployed when an electric power failure occurs.

The AAIB’s preliminary report – it is yet to come out with the final one – indicated that the switches controlling fuel to the aircraft engine moved from ‘RUN’ to ‘CUTOFF’ position within a second of each other, three seconds after liftoff. No cause for the switch movement, which led the engines to shut off, was given.

Beasley Allen shared video and preliminary data analysis from a series of flight simulator tests in a letter on June 11 to the Secretary, US Department of Transportation, Air Accidents Investigation Branch of the UK, and the US Administrator of the Federal Aviation Administration. The tests, said the firm, were conducted on a full-motion certified 787 flight simulator, by the Federation of Indian Pilots (FIP), in the presence of Andrews.

Andrews told The Indian Express: “The letter has been provided (to the US and UK authorities) encouraging them to consider the results of simulator testing because the RAT timeline appears to conflict with the preliminary report timeline.” While the US is involved as Boeing is an American company, 50 UK nationals died in the crash.

The letter by Beasley Allen to their authorities 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. Specifically, the preliminary report states (based on VT-ANB FDR data) that fuel system interruption occurred at 08:08:42 UTC (Universal Time Coordinated) with hydraulic power produced by the RAT 4-5 seconds later. However, flight simulator testing indicates that RAT generated power is not produced until around 18 seconds following fuel system interruption. If the VT-ANB RAT power generation timestamp is accurate, and if the simulator tests are representative of real-world performance, then the tests indicate that the VT-ANB RAT device had to have been deployed and spinning up many seconds prior to fuel system interruption’, the letter states.

The letter further states, “In short, the tests indicate that the RAT deployment may be unrelated to fuel system changes and instead may be a symptom of faults occurring prior to any fuel disruption. Further, although the preliminary report contains photos showing that the RAT is out and visible immediately after takeoff, still-frame images captured from video from an Ahmedabad airport security camera appear to show the RAT is already out on the runway just BEFORE the aircraft rotates for takeoff. Taken together these pieces of evidence tend to indicate that the RAT deployment (a potential symptom of electrical system failure) was not caused by alleged pilot induced fuel system changes.”

The AAIB preliminary report stated that fuel cutoff to the first engine happened at 08:08:42 UTC, to the second at 08:08:43 UTC, and RAT hydraulic power started around 08:08:47 UTC (or after a 4-second gap).

Andrews had previously requested information under the Freedom of Information Act in the US to access black box and flight data for independent review of the crash. This request is still pending.

Ritu Sharma is an Assistant Editor with The Indian Express' Gujarat bureau, an editorial position that reflects her experience and Authority in regional journalism. With over a decade of concentrated reporting experience, she is a highly Trustworthy and specialized journalist, especially noted for her Expertise in the education sector across Gujarat and previously Chandigarh. Expertise Primary Authority (Education): With over ten years of dedicated reporting on education in both Gujarat and Chandigarh, Ritu Sharma is a foremost authority on educational policy, institutional governance, and ground realities from "KG to PG." Her coverage includes: Higher Education: In-depth scrutiny of top institutions like IIM-Ahmedabad (controversies over demolition/restoration of heritage architecture), IIT-Bombay (caste discrimination issues), and new initiatives like international branch campuses in GIFT City. Schooling & Policy: Detailed coverage of government schemes (Gyan Sadhana School Voucher Scheme), the implementation and impact of the Right to Education (RTE) Act, teacher recruitment issues, and the impact of national policies like the NEP. Student Welfare: Reporting on critical issues such as suicide allegations due to caste discrimination, and the challenges faced by students (e.g., non-delivery of NAMO tablets). ... Read More