Air India 787 Switch Tests Found No Defect After Crash
India’s civil aviation ministry has reported a key new finding in the investigation of the June 12, 2025 Air India Flight AI-171 crash in Ahmedabad: testing at Boeing in Seattle found no structural defect in the Boeing 787’s fuel control switch locking hardware, even though flight recorder data previously showed both switches moved from RUN to CUTOFF just after takeoff. In a late-July 2026 statement to Parliament, Minister of State for Civil Aviation Murlidhar Mohol said stress and structural checks of the switches’ latching elements and interlocks found no abnormality, while examination of the wider thrust-control module is continuing.
That matters because the crash killed 241 of the 242 people on board and 19 people on the ground, yet still has no final cause. The new result narrows the field: it weakens a simple explanation based on broken switch hardware, failed detents, or a faulty lockout feature, but it does not explain why both engines lost fuel after takeoff.
The July 2025 interim report from India’s Aircraft Accident Investigation Bureau said flight recorder data showed the two engine fuel control switches were moved sequentially from RUN to CUTOFF and then back again immediately afterward. On this aircraft, moving a fuel control switch to CUTOFF stops fuel flow to its engine. The switches sit below the thrust levers and are normally used during engine start and shutdown on the ground, not as part of a normal climb after departure.
From a systems perspective, the latest finding is important because it separates a visible cockpit control from the larger chain behind it. The switch itself is not just a simple toggle. It uses a lift-before-flip release design and side guards intended to prevent accidental activation. If structural testing found no defect in the latches and interlocks, investigators still have to determine whether the recorded movement reflected deliberate input, an upstream command path issue, or some other unresolved interaction inside the broader thrust-control assembly. The ministry has said analysis is therefore being expanded to the full thrust-control module rather than ending with the switch hardware alone.
That distinction is critical for operators and regulators. A defective latch or broken interlock would point toward a more direct fleet-level hardware concern and could have driven broader mandatory physical inspections or retrofit action. Instead, India’s DGCA had already ordered precautionary inspections of fuel-switch locking mechanisms on domestic Boeing 787s and selected 737s, and Air India reported no defects. Authorities globally also did not impose a general Boeing 787 grounding or mandatory redesign based on the initial data available.
The operational context also explains why the investigation remains technically difficult. The aircraft, a Boeing 787-8 flying from Ahmedabad to London Gatwick, lost engine thrust about 32 seconds after takeoff at low altitude, with outside temperatures above 40 degrees Celsius, then crashed into the BJ Medical College complex about 1.7 kilometers beyond the airport grounds. At that stage of flight, there is little time and little energy margin to diagnose and recover from a dual-power loss, which is why even a narrowed finding still leaves major unanswered questions about sequence, command source, and recoverability.
Human factors also remain unresolved and should be handled carefully. The interim report said one pilot briefly asked the other why the engines had been shut down, but it did not publish a detailed transcript assigning each voice. Investigators have continued reviewing the cockpit voice recorder, while representatives from Indian pilot groups have raised concerns about possible upstream electrical malfunction. Submissions cited in court proceedings also referred to deployment of the Ram Air Turbine, the emergency generator, as a possible sign of a broader electrical event. Those points remain part of the inquiry, not official conclusions.
The investigation is also still moving through the formal international process used for major airliner accidents. According to court filings reported in July, the AAIB expected to complete investigative activities within weeks, with a draft final report likely by October, after which it would be shared with the U.S. National Transportation Safety Board under international procedures. Readers who want to inspect that timing and process can review the reported Supreme Court filing details in The Hindu’s coverage of the AAIB affidavit.
For Boeing 787 operators and the flying public, the present takeaway is narrower than many headlines imply but still meaningful. Investigators appear to have ruled out an obvious mechanical defect in the fuel-switch locking hardware. That is not the same as ruling out the entire control path, ruling in pilot action, or establishing an electrical failure. Until the thrust-control module work and voice-recorder analysis are complete, the most defensible conclusion is that one hardware theory has been weakened, while the larger question of why both engines lost fuel immediately after takeoff remains open.
In accident investigation, ruling out a plausible failure mode is real progress, even when it feels unsatisfying. Here, it shifts attention from the switch’s physical lock to the wider command and control chain a reminder that in modern transport aircraft, the hardest safety questions often sit at the boundary between hardware, control logic, and human interaction rather than in a single broken part.
By Thomas Caldwell — AMI’s senior editor for mechanical and mobility engineering, covering vehicle electronics, systems integration, electrification, chassis systems, propulsion, and safety policy.
