Pilots’ body flags gaps in Air India crash report, calls for fresh probe to verify timeline, RAT deployment

The Federation of Indian Pilots (FIP) has written to the Aircraft Accident Investigation Bureau (AAIB), flagging discrepancies in the preliminary report on the Air India Flight AI171 crash. Highlighting that the deployment of the Ram Air Turbine (RAT) may not be linked to the fuel interruption and raising doubts on the timeline, the FIP has called for fresh simulator tests to verify the sequence of events. This comes as the AAIB on Friday (Jun 12) released an interim report on one of the deadliest aviation disasters in the country, marking its one-year anniversary. The crash claimed the lives of 260 people on board and on the ground, leaving just one surviving passenger.

What did the FIP say?

The pilots’ body raised concerns about whether Boeing 787 simulator results align with the timeline outlined in the AAIB’s preliminary findings, which stated that the aircraft’s emergency RAT was deployed after the fuel control switch movement. The FIB suggested that the RAT deployment may have occurred due to an electrical fault or other existing issue, adding that it may have deployed before the fuel switch movement.

The FIP also cited flight simulator data indicating that the RAT typically begins generating power roughly 18 seconds after a fuel interruption. On this basis, it argued that the RAT deployment might not be directly linked to fuel switch movement.

“While the report indicates RAT power generation approximately 4-5 seconds after fuel interruption, simulator testing reportedly indicates approximately 18 seconds. The letter therefore suggests that RAT deployment may have occurred before fuel control switch movement and may indicate an earlier system or electrical fault requiring further investigation,” the letter read.

Referring to CCTV footage from Ahmedabad airport, the letter noted that the RAT appeared to already be deployed while the aircraft was still on the runway before rotation. This, it said, further strengthens the possibility of an earlier system anomaly rather than a fuel-control-triggered event.

The letter additionally highlighted a series of events leading up to the crash, including a loud explosion-like sound, a noticeable dimming of cabin lights, and multiple ACARS maintenance messages sent before takeoff. It suggested that these elements, along with damage patterns seen in the aft flight recorder imagery, should be analysed together to reconstruct a clear and consistent timeline and to assess whether an electrical failure played a role.

The association urged the investigating agency to independently verify the acceleration data in the preliminary report and to closely examine the relationship between RAT deployment, hydraulic power generation, and fuel control switch movement. The FIP recommended that these aspects be fully addressed in the final investigation report.

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