Flight BA295, a Boeing 777, was squawking 7700, the code that tells air traffic control a crew needs priority handling. Flightradar24 data showed the aircraft dropped to around 9,000 feet while crossing the Atlantic, a fall of some 28,000 feet within minutes.

British Airways flight BA295 declared an emergency and turned back to the U.K. after a sudden descent post-takeoff from Heathrow.

British Airways Flight BA295, operating from London Heathrow to Chicago O'Hare, squawked 7700, the international emergency transponder code, while flying over Ireland.