A preliminary report reveals the last communication between Air India flight 171 pilots, questioning fuel cut-off actions moments before their tragic crash in Ahmedabad, resulting in 260 fatalities.

India’s aviation watchdog says more investigation needed into mid-air engine switch sequence that preceded world’s deadliest air disaster in over a decade.

The two engines on the Air India flight shut down within one second of each other before the Boeing 787 Dreamliner crashed last month in Ahmedabad, India, killing at least 260 people, according to a preliminary report released Friday.