Less than an hour into the journey the crew signalled a serious problem on board.

19:03, Sat, May 2, 2026 Updated: 19:04, Sat, May 2, 2026

Air Canada plane ascending

The Air Canada flight was escorted by emergency vehicles (Image: NurPhoto via Getty Images)

An Air Canada flight bound for Toronto was forced to make an emergency return to Heathrow Airport after a mid-air scare shortly after take-off.

Flight AC853 departed at 08:34 BST on Saturday and climbed to 34,000 feet, heading out over the Atlantic as scheduled.

However, less than an hour into the journey, the crew issued a Squawk 7700 signal – a code used to alert air traffic control to a serious problem onboard.

The aircraft, a Boeing 777-300ER, quickly abandoned its transatlantic route and carried out a controlled turnaround back towards London, with emergency services placed on standby.

Tracking data indicates the jet began its return shortly after reaching cruising altitude at around 09:15 BST before descending towards the capital.

Plane diverted on AirLive data map

Data indicating Air Canada flight AC853's U-Turn (Image: AirLive)

Get travel news and expert holiday advice plus selected offers and competitions Invalid email

We use your sign-up to provide content in ways you've consented to and to improve our understanding of you. This may include adverts from us and 3rd parties based on our understanding. You can unsubscribe at any time. Read our Privacy Policy

The plane touched down safely on runway 27L at approximately 10:02 BST. Landings on Heathrow’s south runway were briefly suspended as a precaution while emergency crews responded in line with standard protocol.

The aircraft later taxied to the gate under escort from emergency vehicles, with passengers taken back to the terminal.

Air Canada has not yet confirmed the cause of the emergency, with such alerts typically triggered by a range of issues including technical faults or medical incidents.

No injuries have been reported following the incident.

The airline has since arranged a replacement departure later the same morning, while the situation is expected to be reviewed by both the airline and airport authorities.