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The AIR INDIA flight 171 crash initial report indicates that the fuel cutoff switches for both engines switched from the RUN position to CUTOFF one after the other, with a one-second interval between them.
The preliminary report from the Aircraft Accident Investigation Bureau regarding the Air India flight 171 crash, which tragically took the lives of 260 individuals on June 12, has been released. This report outlines the first official details of the incident. Here are the key findings and their implications for the ongoing investigation.
What caused the crash?
The preliminary report indicates that at 08:08:42 UTC, both engine fuel cutoff switches moved from the RUN position to CUTOFF sequentially, with a one-second interval in between. This occurred just as the aircraft reached its maximum speed of 180 knots during takeoff, leading to an immediate loss of power in both engines due to the disruption of fuel supply. However, the report does not clarify the cause behind the activation of the fuel switches—whether it was due to human intervention, mechanical failure, or an electronic issue. This critical aspect remains unresolved and is currently the focus of the ongoing investigation.
What potential causes have been ruled out?
The investigation has eliminated several possible factors:
– Weather conditions: Described as good with light winds and clear skie
– Bird strike: No evidence found in CCTV footage or physical examination
– Aircraft configuration: Flaps were correctly set at 5 degrees for takeoff, landing gear was retracting normall
– Weight and balance: Aircraft was within normal operating limits
– Fuel quality: Samples from airport fuel trucks tested satisfactory
– Pre-existing engine problems: Both engines appeared to be operating normally until the fuel cutoff
Does this mean the pilot was responsible?
We still don’t have all the answers. The cockpit voice recording captured an important moment: one pilot questioned the other about the fuel cut-off, to which the second pilot claimed he hadn’t done it. This indicates that although one pilot recognized the fuel had been turned off, the other denied taking that action.
While the denial does not conclusively eliminate the possibility of human error, it does imply that the fuel cut-off might have occurred without intent.
What happened in the cockpit?
The flight was under the command of First Officer Clive Kunder, who was acting as the pilot flying (PF), while Captain Sumeet Sabharwal served as the pilot monitoring (PM). This arrangement is typical, with the more junior pilot taking control of the aircraft and the senior captain overseeing the operation.
The report presents a summarized version of the cockpit communications related to the fuel cut-off, without any direct quotes or verbatim statements. The AAIB notes that “one of the pilots is heard asking the other why did you cutoff,” to which the other pilot replied, “I did not do so.”
However, the report does not clarify which pilot made each comment. A further analysis of the cockpit voice recorder could shed light on the crew’s communications and any relevant audio, including alarm sounds.
Could the crew have recovered the plane?
The pilots made a courageous effort to recover the aircraft. Just 10 to 14 seconds after the fuel was cut off, they promptly switched both fuel controls back to the “RUN” position—Engine 1 at 08:08:52 UTC and Engine 2 at 08:08:56 UTC. This initiated automatic restart sequences for both engines, with Engine 1 showing positive signs of recovery, while Engine 2 was attempting to relight.
Despite the challenges, recovery wasn’t achievable because there simply wasn’t enough time and altitude. The aircraft was only about 625 feet off the ground when the engines failed, while restarting the engines requires significantly more time than the 29 seconds left before impact. Although modern jet engines can be restarted in flight, they usually need several minutes and a higher altitude to do so effectively.
Were there any problems with the plane?
The aircraft VT-ANB has maintained a solid maintenance history, showing no reported issues with the fuel control switch since 2023. All necessary inspections are up to date, and the aircraft holds valid airworthiness certificates.
However, there is an important safety consideration to note. In 2018, the U.S. Federal Aviation Administration released Special Airworthiness Information Bulletin (SAIB) No. NM-18-33, which highlighted potential concerns with the locking mechanisms of fuel control switches on various Boeing models, including the 787. This bulletin emerged following reports that some Boeing 737s had fuel control switches installed without their locking features properly engaged.
Importantly, Air India opted not to conduct the recommended inspections from the bulletin, as it was advisory rather than a requirement. While the airline has replaced the aircraft’s throttle control module twice—in 2019 and 2023—these replacements were unrelated to any fuel switch concerns.
What did the switches advisory pertain to?
In 2018, the FAA released a bulletin highlighting issues with the fuel control switch locking mechanisms that could potentially disengage. These mechanisms are meant to stop accidental movement of the fuel switches. If they become disengaged, vibrations, unintended contact, or other influences could easily shift the switches.
Although the FAA did not deem this to be serious enough for a mandatory directive, the bulletin did suggest conducting inspections to ensure that the locking mechanisms are fully engaged.
What happens next?
It’s crucial to highlight that this is just an initial report, and the conclusions may evolve considerably as further evidence is collected and examined. The AAIB underscores that “the information is preliminary and subject to change.”
The investigation continues with several key areas of focus:
- Investigators are conducting a thorough analysis of the black box data, having completed an initial review. They are examining approximately 49 hours of flight data and two hours of voice recordings in search of further insights.
- A careful assessment of the limited fuel samples collected from the aircraft is underway.
- The mechanical evaluation of the fuel control switches and associated components is being performed to check for any malfunctions.
- Additional interviews are being held with witnesses, relevant individuals, and technical experts.
- The AAIB has indicated that “more information is being gathered based on initial leads” and that the investigation team will “review and examine further evidence, records, and information requested from stakeholders.”
- A conclusive report aimed at determining the probable cause and making safety recommendations will take several months, or possibly years, to finalize.
