Authorities investigating the Air India AI-171 plane crash have both black boxes, meaning we can unravel the final seconds and understand why the Boeing 787-8 Dreamliner crashed.

An Air India flight returned to Hong Kong on Monday shortly after takeoff due to a midair technical issue, days after another of the airline’s flights crashed and killed at least 270 people.

Bob Blackman, MP for Harrow East, said it was believed to be the highest number of British deaths ever recorded in a plane crash, with 53 UK nationals on board.