The US aircraft manufacturer Boeing finds itself the focus of an international controversy once again, with India and South Korea ordering fuel switch inspections for Boeing jets after a 787-8 Dreamliner crashed in Ahmedabad last month.

Individual airlines in Japan and Singapore started their own checks as a precaution, according to Reuters.

The London-bound Boeing jet collided with a structure just minutes after takeoff. The crash killed 19 people on the ground and all but one of the 242 people onboard the aircraft.

Pilots discussed fuel intake

Indian officials are still trying to determine the cause of the tragedy, the deadliest aviation accident in a decade. However, the nation's Aircraft Accident Investigation Bureau (AAIB) published a preliminary report this week, claiming that the fuel switches for both of the plane's engines moved to the "cutoff" position almost immediately after takeoff, starving the engines of fuel.

It is not yet known if this was done by one of the pilots or due to a mechanical fault. While the 15-page report does not provide a full transcript of the pilots' conversation, the authorities shared a snippet indicating confusion in the cockpit.

"In the cockpit voice recording, one of the pilots is heard asking the other why did he cutoff. The other pilot responded that he did not do so," AIIB officials said.

The report also notes that fuel switches moved to "run" seconds later. One of the engines apparently started cycling toward recovery, while the other continued to struggle. This was not enough to maintain flight and the plane crashed after less than a minute in the air.

'Cloud of mystery' surrounds Air India crash

Commenting on the preliminary report, aviation expert Sanjay Lazar who has worked with Air India for 37 years, said that the document "raises more questions" than it answers.

He also said it was "regrettable" that the full cockpit transcript has not been made public.

The AAIB-provided notes on the pilots' conversation indicate that "either none of them cut it off and it got cut off some other way, or... there was some element of subterfuge. So it adds a cloud of mystery over that," he told DW.

With the focus of the probe moving onto Boeing's fuel intake controls, Lazar pointed to two directives issued by the US Federal Aviation Administration (FAA) possibly relating to the issue.

In the first, non-mandatory directive in 2018, FAA warned that these fuel switches could have a fault and advising supervisory bodies to check them. The second one in 2022, however, was mandatory — and it focused on engine fire control panel and engine fire control switches.

According to Lazar, the FAA said checks were necessary due to reports that foreign object debris "may have been introduced during maintenance or rework" of certain units, with one of the risks associated with it being an "uncommanded activation of the engine fuel shutoff."

Air India admitted not following up on the first, non-mandatory directive. It was not immediately clear if the airline took action on the 2022 order.

Air India also said its maintenance records for the crashed jet showed that the throttle control module, which includes the fuel switches, was replaced in 2023. However, "the reason for the replacement was not linked to the fuel control switch," the AAIB said in their preliminary report.

In recent days, news agencies reported that Boeing was assured airlines its fuel switch locks were safe.

Air India CEO says no issue with fuel quality

According to media reports, Air India CEO Campbell Wilson issued an internal memo on Monday acknowledging that the preliminary AAIB report "provided both greater clarity and opened additional questions."

"I urge everyone to avoid drawing premature conclusions, as the investigation is far from over," he said.

Wilson also said all mandatory maintenance and checks were completed on the Boeing aircraft.

"There was no issue with the quality of fuel and no abnormality with the take-off roll. The pilots had passed their mandatory pre-flight breathalyser and there were no observations pertaining to their medical status," he said in the note.

Pilot group wants seat at table

On Tuesday, Singapore Airlines said it had completed the inspection of its 787 fleet, including planes used by its low-cost subsidiary Scoot, and confirmed all were functioning properly. Germany's Lufthansa group also said it rechecked fuel switches on its own 787s in the wake of the Air India crash, and found no faults.

Indian officials are due to submit their findings regarding fuel switches by next Monday. The final report on the crash, however, is likely to take a year or longer.

Meanwhile, the Airline Pilots' Association of India (ALPA India) requested to be included as observers to provide "the requisite transparency" in the official probe.

"We feel that the investigation is being driven in a direction presuming the guilt of pilots and we strongly object to this line of thought," ALPA India president Sam Thomas said in a statement issued over the weekend.

Boeing's PR nightmare continues

Whatever the outcome of India's and other probes, the latest Boeing crash is likely to further degrade the already shaky reputation of the US airspace giant.

Boeing has been struggling to recover from two fatal crashes in 2018 and 2019, both of them involving 737 Max jets. While multiple factors contributed to both tragedies, both were linked to the plane's Manoeuvring Characteristics Augmentation System (MCAS), which is designed to automatically push the plane's nose down if it detects a danger of stalling.

Between the 2019 crash and the latest incident in India, Boeing aircraft were involved in a series of smaller midair emergencies, such as a door ripping off of an Alaska Airlines 737 Max-9 in January 2024, or a 787 suddenly dropping during flight and leaving some 50 people injured in March 2024. Some two months later, one person died when a Boeing 777 hit turbulence while flying from London to Singapore.

Multiple whistleblowers have also publicly raised concerns about production issues and alleged safety gaps in Boeing's production process, though achieving clarity on the complaints has proven to be difficult.

In March 2024, a Boeing former employee who had recently been giving evidence against the company in a whistleblower suit died of what police later said was a self-inflicted gunshot wound. Weeks later, another whistleblower passed away after a short illness, after coming down with a fast-spreading infection and developing pneumonia.

Edited by: Srinivas Mazumdaru