Indian investigators have successfully downloaded crucial data from the flight recorders of the Air India Boeing 787 Dreamliner that crashed shortly after takeoff from Ahmedabad earlier this month, claiming 260 lives, the country’s civil aviation ministry said on Thursday.

The ill-fated flight, bound for London, went down minutes after departing from Ahmedabad on June 12, killing 241 of the 242 passengers and crew on board, as well as several individuals on the ground. The crash is considered the deadliest in the past decade globally.

Recovery efforts led to the discovery of the two black boxes – the cockpit voice recorder (CVR) and the flight data recorder (FDR) – with one retrieved from debris on June 16 and the other found on the rooftop of a nearby building on June 13.

According to the ministry, data from the forward flight recorder was accessed on Wednesday by a team comprising India’s Aircraft Accident Investigation Bureau (AAIB) and the United States National Transportation Safety Board (NTSB), marking a significant step forward in the probe.

“These efforts aim to reconstruct the sequence of events leading to the accident and identify contributing factors to enhance aviation safety and prevent future occurrences,” the ministry said in a statement.

The involvement of the NTSB comes as part of international cooperation. NTSB Chair Jennifer Homendy, speaking to Reuters on the sidelines of an aviation event, said the US team has been working diligently to assist Indian authorities. “We have had excellent cooperation from the Indian government and the AAIB,” she said.

Homendy expressed hope that Indian officials would share the findings of the investigation publicly and swiftly, citing the importance of transparency for aviation and public safety.

While the exact cause of the crash remains under investigation, a source familiar with the probe indicated that the aircraft began losing altitude after climbing to just 650 feet, raising concerns about a possible issue with engine thrust.

The Wall Street Journal reported that investigators suspect the aircraft’s emergency power generator may have been active at the time of the crash — a detail that could have significant implications.

The twin GE recorders on Boeing 787 jets, located at the front and rear of the aircraft, are designed to capture identical flight data. These recorders were manufactured by General Electric (GE), which also built the engines of the downed aircraft. GE experts were sent to India to assist in the analysis.

Notably, the forward recorder includes an independent backup power supply that can operate the device for approximately 10 minutes in the event of a total power failure, a feature highlighted in an earlier 2014 NTSB report.

However, the timing of the data retrieval has drawn scrutiny from aviation safety experts. It took nearly two weeks to begin downloading the data – a delay three specialists told Reuters is unusual in the aftermath of a high-profile air disaster.

Anthony Brickhouse, a US aviation expert, said, “Normally countries know that the world is watching. In such high-profile cases, recorders are accessed swiftly and updates provided.”

There was initial speculation that the black boxes might be sent to the United States for analysis, but India clarified last week that a final decision on their examination location had not yet been taken. The government maintained that all actions were being carried out in compliance with domestic regulations and international protocols.

A preliminary report into the crash is expected within 30 days of the accident. Most air crashes, experts note, are the result of a confluence of several factors rather than a single cause.