Air Canada flight declares emergency after Heathrow take-off as landings suspended

Passengers on an Air Canada flight had to return to London Heathrow after an emergency was declared. The emergency was called just after take off on the plane bound for Toronto on Saturday morning. Flight AC853 , a Boeing 777-300ER, departed Heathrow at 8.34am before heading back. It had reached a cruising altitude of 34,000ft and was heading over the Atlantic when the pilots on board turned the plane around, according to flight tracking data. A 7700 emergency code was emitted from the plane at 9.30am, nearly an hour after the plane had taken off and so far it is unclear what the problem was with the flight. The plane landed back at Heathrow at 10.02am on runway 27L and passengers were escorted back to the terminal after the plane had taxied to the gate. Landings on the runway were temporarily suspended. The airline arranged a replacement departure later the same morning, while the situation is expected to be reviewed by both the airline and airport authorities. When a pilot enters the four-digit emergency code 7700 into their transponder, it immediately alerts air traffic control that the aircraft is in distress and requires priority handling. The exact nature of the incident is unclear as it acts as a "catch-all" for any emergency situation that isn't a hijacking (7500) or radio failure (7600). When a plane does emit 7700, a special procedure is put in place at the airport where it is due to land which includes emergency services on standby. The Boeing 777-300ER is one of the most used planes in the Air Canada fleet. The Mirror has contacted Air Canada for comment. Last month a Ryanair flight heading from the UK to Portugal declared a mid-air emergency moments after take-off. Flight FR5552 left London Stansted airport at 6.21am on April 12, heading for Faro , but had to turn back shortly after passing over northern France. And rather than returning to the busy airspace of London Stansted, the flight crew decided to divert to Bournemouth Airport. It was around 45 minutes into the journey that the 7700 emergency was declared, leading to a quick descent. The Ryanair plane could be seen on radar tracking making a sharp turn and losing height as it headed to the English coast and Bournemouth Airport. It landed safely in Bournemouth just over an hour after its initial departure. AirLive reports there was a medical issue on board.