Air India crash report puts focus on Boeing 787 fuel switch design; here's why

While the switches are gated to prevent accidental movement, a prior FAA warning highlighted a potential lock malfunction similar to issues found in 737s. Experts suspect a system fault, as both switches may have moved without pilot input.

Ahmedabad Air India crash: The preliminary report by the Aircraft Accident Investigation Bureau (AAIB) has put the spotlight on the fuel control switches on a Boeing 787-8. The switches are part of the engine start and shutdown system, crucial for managing the fuel flow to each engine. The switches are located between the two pilots’ seats on the center pedestal, behind the throttle levers.

According to the report, the cause of the crash was likely to be a shutdown of the engines due to both fuel control switches moving to CUTOFF position during the initial climb, shortly after takeoff.

How fuel control switches work

For the engine to start, the pilot moves the switch from CUTOFF to RUN. This allows fuel to enter the engine’s combustion chamber, initiating the engine start sequence. The engine’s Full Authority Digital Engine Control (FADEC) takes over, managing ignition and fuel flow. For the engine to turn off, the switch is moved from RUN to CUTOFF and fuel supply is stopped. On the 787 flights, the fuel switches are physically gated to prevent accidental movement, which requires the pilot to do the action. The locking feature is intended to prevent uncommanded or inadvertent shutdown. 

In 2018, the Federal Aviation Administration (FAA) had warned that the fuel switch lock might not work right on some planes. This problem was found in 737s and could also affect 787s because they use a similar design. In the case of the Air India plane crash in Ahmedabad, the conversation between the two pilots reveal that neither pilot intentionally moved the switches. What might have happened is that both fuel switches unexpectedly moved from RUN to CUTOFF within a second of each other, causing both engines to shutdown and the aeroplane to lose thrust. The pilots may have tried to turn it back on as the position of the switch was found to be in RUN after the crash.

Experts warns of Boeing system fault

Several experts have highlighted that the issue might have been with the Boeing system rather than pilots. Veteran aviation safety expert and CEO of Martin Consulting Mark D Martin said, “This isn't a mistake a trained pilot would make. It's something deeper. Possibly darker. These aren't buttons you can bump by accident,” he added, suggesting that a potential system malfunction may have triggered a dangerous glitch that flips the fuel switches without pilot input.

The investigation is ongoing, with detailed analysis of the voice and flight data currently underway. Fuel samples collected from the aircraft and refueling sources have been tested and found satisfactory. Investigators are focusing on the possibility of a mechanical or electrical failure, including the uncommanded activation of the fuel cutoff switches. Statements from witnesses and the lone surviving passenger are being reviewed alongside post-mortem reports to support the technical findings. At this stage, no immediate safety recommendations have been issued for other aircraft or operators.