A preliminary report on the investigation into the Air India flight that crashed last month has answered some questions about the fatal accident but raised many more and fuelled speculation about the cause.

The United States National Transportation Safety Board Chair Jennifer Homendy said on Friday that recent media reports on the crash of an Air India Boeing Dreamliner that killed 260 people were premature and speculative.

The report and India’s inspection order referred to an advisory from the Federal Aviation Administration in 2018 that recommended that carriers using Boeing models, including the 787, inspect the locking mechanism of the fuel control switches to ensure they could not be moved accidentally.