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The preliminary report released by the Aircraft Accident Investigation Bureau (AAIB) into the devastating Air India Flight 171 crash in Ahmedabad paints a chilling picture of a sequence of events that led to the loss of 260 lives. The report, while stopping short of assigning blame, highlights the inexplicable simultaneous cutoff of fuel to both engines shortly after takeoff. This single event, captured in cockpit voice recordings and corroborated by flight data, has become the focal point of the investigation, raising profound questions about the cause and circumstances surrounding this tragic incident. The report confirms that within one second, both engine fuel control switches were moved from the “RUN” position to “CUTOFF,” effectively starving the engines of fuel and causing a catastrophic loss of thrust. The cockpit voice recorder captured a pilot questioning the other, “Why did you cut off?” to which the other pilot denied any involvement. This exchange underscores the mystery surrounding the switches’ movement and fuels speculation about potential causes, ranging from mechanical or electrical malfunction to unintentional human error or even a deliberate act. Despite the pilots’ swift response in relighting both engines, only one engine recovered fully before the aircraft tragically crashed a mere 32 seconds after becoming airborne. The switches were subsequently found back in the “RUN” position, further compounding the enigma. The AAIB's preliminary findings effectively eliminate several potential contributing factors. Mechanical failure, bird strike, and fuel contamination were all ruled out following thorough investigations and laboratory tests. Samples taken from refueling bowsers and tanks were deemed satisfactory, indicating no issues with the fuel supply. Similarly, a comprehensive review of the aircraft's maintenance records revealed no pre-existing mechanical defects that could have directly contributed to the engine failure. This process of elimination narrows the focus of the investigation and intensifies the scrutiny on other possible explanations. The report also addresses the aircraft's airworthiness prior to the flight. All mandatory checks had been completed, and the aircraft met the necessary safety standards. However, it was noted that an advisory issued by the FAA in 2018 concerning fuel switch locking mechanisms was not acted upon, as it was classified as non-mandatory. While this advisory did not directly cause the crash, it raises questions about the potential for preventative measures that could have mitigated the risk of accidental switch manipulation. The flight crew's qualifications and adherence to procedures were also examined. Both pilots passed pre-flight breathalyzer tests and were observed on CCTV footage prior to departure. The captain, Sumeet Sabharwal, possessed extensive flying experience with over 15,000 flight hours, including 8,600 on the Boeing 787. The First Officer, Clive Kunder, had 3,400 hours of flying experience. During the flight, Captain Sabharwal was monitoring, while First Officer Kunder was the pilot in control. The AAIB's preliminary report, while providing crucial details and eliminating certain possibilities, leaves several critical questions unanswered. The primary mystery revolves around the inexplicable movement of the fuel control switches. The report does not provide a definitive explanation for how the switches were moved to the “CUTOFF” position, sparking intense speculation and further investigation. Several potential scenarios are being explored, including the possibility of a malfunction in the engine electronic control unit (ECU). Veteran commanders have cited a 2021 joint FAA–GE Service Bulletin recommending the replacement of the “MN4 microprocessor” on the engine’s ECU. This bulletin suggests that solder-ball fatigue due to thermal cycling could lead to electrical faults, potentially triggering unintended switch activation. If the ECU malfunctioned and sent erroneous signals, it could plausibly have caused the fuel switches to move unexpectedly. Another puzzling aspect of the crash is the fact that the landing gear remained down throughout the emergency. The report notes that the crew was likely preoccupied with attempting to restart the engines and regaining control of the aircraft, leaving them with no opportunity to retract the gear. Audit transcripts reveal that the standard “positive climb” or “gear up” call was not made during the initial moments of flight. The extended landing gear would have significantly increased drag on the aircraft, exacerbating the challenges faced by the pilots in their attempt to recover from the engine failure. The absence of cockpit video recording is another significant limitation in the investigation. Experts like Peter Goelz of the NTSB have lamented the lack of visual evidence, which could definitively identify who moved the switches and provide valuable insights into the crew's actions during the critical moments leading up to the crash. The lack of video evidence hampers the investigation's ability to reconstruct the events in the cockpit with complete accuracy. Furthermore, questions have been raised regarding the performance of the Emergency Locator Transmitter (ELT). Despite the severity of the impact, which generated forces of 3.2 to 3.5 g, the ELT failed to emit a distress signal. This failure raises concerns about the reliability of the ELT system and the potential for future incidents where a functioning ELT could provide crucial information to rescue teams. The composition of the AAIB investigation team has also come under scrutiny. Concerns were raised about the expertise of the initial team members, leading to the inclusion of subject-matter experts, including pilots, engineers, aviation medicine specialists, and flight-recording experts. This expanded team aims to provide a more comprehensive and thorough investigation, ensuring that all aspects of the crash are thoroughly examined. The final report is expected by June 12, 2026. Until then, the AAIB has refrained from declaring a definitive cause or issuing safety directives for 787-8 operators or GE’s GEnx-1B engines. This cautious approach reflects the complexity of the investigation and the need for a thorough understanding of all contributing factors before making any definitive conclusions or recommendations. The Air India Flight 171 crash remains a complex and tragic event, with many unanswered questions. The AAIB's ongoing investigation is crucial in determining the root cause of the accident and preventing similar tragedies from occurring in the future. The final report is eagerly awaited by the aviation industry, the families of the victims, and the public at large. The findings of the investigation will have far-reaching implications for aircraft design, maintenance procedures, and pilot training. Ultimately, the goal of the investigation is to learn from this tragedy and enhance the safety of air travel for everyone.
Source: Air India crash: What AAIB report confirms, what it rules out, what still remains unanswered