Pilots’ Body Presses AAAIB For Deep Electrical Probe In Air India AI-171 Crash Investigation

The Federation of Indian Pilots (FIP) has appealed to the Aircraft Accident Investigation Bureau (AAIB) to conduct an exhaustive evaluation of the Boeing 787's electrical and avionics architecture as part of the ongoing probe into the fatal Air India Flight AI-171 crash. The latest request comes less than a month before the crash's final investigation report, which is expected in October.

Pilots’ Body Raises Questions Over Simulator Timeline Data

In a letter sent to the Director General of the AAIB on September 18, the pilots' association called for closer scrutiny of external technical data and raised critical questions regarding discrepancies in flight simulator timelines. A central focus of the representation concerned thr technical evidence derived from Boeing 787 simulator testing conducted by legal representatives of the victims' families. According to the FIP, these tests revealed a noticeable divergence between the official preliminary timeline and observed aircraft behavior.

The simulator results, which were earlier published by The Free Press Journal, suggested that the interval between fuel interruption and the availability of hydraulic power generated by the Ram Air Turbine (RAT) does not match the initial official account. The FIP noted that if the recorded RAT power generation timestamps are accurate, the emergency deployment of the RAT may have occurred before the dual fuel switches transitioned to the "CUTOFF" position.

Boeing 787’s Electrical Architecture Under Focus

"Establishing the accuracy of these timings is essential not only for determining the precise sequence of events in the AI-171 crash but also for ensuring that any resulting safety recommendations are based upon a technically robust and scientifically validated understanding of the accident," the letter, written by FPI president Capt CS Randhawa, stated. The association requested that the AAIB conduct or supervise formal simulator validation exercises to reconcile these differences.

The letter emphasised that the Boeing 787 Dreamliner operates on a "More Electric Aircraft" architecture, replacing traditional pneumatic and hydraulic systems with electrically driven components linked through digital networks.

Given this high level of system integration, the FIP argued that transient electrical disturbances, voltage fluctuations, data-bus anomalies, power interruptions or battery short-circuits could cause widespread system interaction issues. The pilots' body referenced its earlier technical notes, which proposed a potential electrical reverse-voltage pathway – triggered by a battery short circuit – as a potential cause for the dual fuel switches moving to "CUTOFF".

Request For Review Of Maintenance Records And Aircraft Data

To determine whether recurring faults were present,

The FIP has requested a full review of the accident aircraft’s historical maintenance logs, including technical logs, maintenance records and deferred defects under the Minimum Equipment List. It also asked for scrutiny of the Aircraft Health Monitoring records and ACARS message chronologies, along with the system performance data.

The representation acknowledged that technical documentation regarding VT-ANB's operational history submitted by the Foundation for Aviation Safety (FAS) was forwarded to the AAIB via a UK AAIB expert on June 10. The FIP urged the investigation team to systematically evaluate and either validate or rule out this material through documented technical analysis.

While reaffirming that it is not advancing a predetermined conclusion regarding the cause of the disaster, the FIP urged the AAIB to issue interim safety recommendations if any systemic vulnerabilities or operational risks are uncovered prior to the final report.