AI171 crash: Boeing 787 had similar fuel switch issue in 2019, says expert

According to US aviation expert Mary Schiavo, a 2019 All Nippon Airways (ANA) flight in Japan experienced a similar issue, with the fuel switch transitioning on its own during final approach, without

The preliminary report on the Air India Flight 171 crash, released by India’s Aircraft Accident Investigation Bureau (AAIB), has brought fresh scrutiny on the Boeing 787’s fuel system. The report highlighted a critical issue: The fuel switch on the aircraft transitioned from “Run” to “Cutoff” shortly before the crash, though it was recovered in the “Run” position from the Ahmedabad crash site.

 

However, this is not the first time a Boeing 787 Dreamliner has experienced such an issue. A similar case of unintended fuel switch transition was reported in a previous incident involving the same aircraft model.

 

Not the first time Boeing 787 experienced such a failure: US expert

 

In an exclusive comment to Financial Express, US aviation expert Mary Schiavo pointed out that this is not the first time such a failure has occurred on a Boeing 787 Dreamliner. She cited a 2019 incident involving an All Nippon Airways (ANA) flight in Japan, where the fuel switch transitioned on its own, without any pilot input, while the aircraft was on final approach.

   

Software glitch caused ANA engine failure

 

Schiavo told Financial Express that an investigation into the ANA incident revealed a software glitch had led to the transition of the fuel switch. The software issue caused the aircraft to mistakenly interpret that it was on the ground, prompting the Thrust Control Malfunction Accommodation (TCMA) system to shut off fuel to the engines, even though the pilots had not activated the fuel cut-off themselves.

 

The ANA flight, a Boeing 787 Dreamliner flying from Tokyo to Osaka with 109 passengers and nine crew members, experienced a dual engine flameout after the pilot deployed the thrust reversers for landing. The aircraft had to be towed from the runway, but no injuries were reported. 

 

Cockpit conversation casts doubt on AI171 pilot error theory

 

The AAIB report also paraphrased a critical exchange between Captain Sumeet Sabharwal and First Officer Clive Kunder. One of the pilots asked why the other had cut off fuel supply to the engine, and the response was that he had not. Moments later, a Mayday call was issued, and AI171 crashed into a hostel for medical students just 15 seconds later.

 

Mary Schiavo rejected suggestions that the crash was caused by pilot error, suicide, or sabotage. Speaking to Financial Express, she said there was no indication of intentional action by the crew and emphasised the need for a thorough analysis of the cockpit voice recorder (CVR). She added that releasing the full CVR transcript would help prevent misinterpretation based on paraphrased excerpts.

 

Both engines of AI171 failed, leaving pilots with no chance of recovery

 

Schiavo told Financial Express that while the Boeing 787 is designed to operate on a single engine, the AI171 crash was more severe, as both engines reportedly lost fuel supply at the same time. This simultaneous failure left the pilots with neither the altitude nor the time required to attempt an engine restart or recover sufficient thrust to keep the aircraft airborne.

 

When asked why the second engine could not be restarted and why the RAM Air Turbine (RAT) failed to provide enough lift or control, Schiavo explained that the window between engine deceleration and impact was extremely narrow. According to her, the aircraft began losing altitude even before it cleared the airport perimeter wall.

 

She pointed out that in-flight engine restarts can take several seconds, some requiring a diving manoeuvre — and the crew simply did not have that kind of time. AI171 went down less than two minutes after it was cleared for take-off. Explaining the RAT’s limited capacity, Schiavo said it is intended only to power essential systems like hydraulics and provide minimal electrical support, just enough to steer the aircraft. 

 

Boeing 787 software flaw must be investigated, says expert

 

Schiavo urged investigators to examine known issues with the Throttle Control Malfunction Accommodation (TCMA) software in Boeing 787 aircraft, reported Financial Express. She pointed out that similar incidents have occurred in the past and that many 787s are of a similar vintage. A key question, she said, is whether the AI171 aircraft had been inspected for those specific software flaws.

 

No action recommended against Boeing, yet

 

Despite the concerns, the AAIB report stated “no recommended actions” for Boeing or its 787-8 Dreamliner aircraft. It said that no directives had been issued for the aircraft, engine operators, or manufacturers at this stage of the investigation.

 

This led to speculation that Boeing may have been given a clean chit. But Schiavo strongly disagreed. She said the report does not absolve Boeing software of scrutiny, and if such an interpretation were made, it would be a serious breach of aviation accident investigation standards, Financial Express reported.