Investigators in India are studying the black boxes of a Boeing 787 Dreamliner after recovering them from the aircraft wreckage to ascertain the cause of last week’s plane crash that left at least 270 people dead.

Since the Tata takeover, India’s Directorate General of Civil Aviation has repeatedly fined Air India over safety and other regulatory violations, including an Rs8mn ($95,000) penalty last year for exceeding flight duty time limits. At home, it is competing in a near-duopoly with IndiGo, which has been boosting its international long-haul routes.

There have been cases of a very small number of survivors in very serious accidents, but it is "very rare" for there to be only one, a professor told Newsweek.