A BA flight declared an emergency after suddenly dropping 28,000ft in just minutes as it flew over Ireland, according to flight data.

The Chicago-bound flight had taken off from London Heathrow Airport at 11.50am on Monday.

But just half an hour into its journey, passengers on flight BA295 experienced a dramatic drop from 36,000 feet to around 9,000 feet – in just seven minutes.

Crew on the jet declared an emergency.

They transmitted a 7700 squawk – a code that tells air traffic control that a flight is experiencing an emergency.

It reportedly continued flying after the steep drop while crew communicated with air traffic control and assessed their options.

The plane was forced to turn back around over Ireland, FlightAware data shows.

It spent four hours zig-zagging across the coast before it could land in London.

BA said the plane had experienced a “technical issue” forcing it to return to the UK.

It eventually landed back at Heathrow just after 5pm after agonising hours spent flying back and forth across the Bristol Channel.

A BA spokesperson said: “The safety of our customers and crew is always our top priority, and the aircraft landed safely after our highly-trained pilots returned to Heathrow following a technical issue.

“Customers disembarked the aircraft normally and our teams are working to get their travel plans back on track as quickly as possible.”

The company did not explain the reason for the emergency.

Its Boeing 777-200ER that was set to complete the eight-hour-40-minute transatlantic route is around 30 years old.

It comes after a flight from England to Turkey was forced to make an emergency landing in Greece this summer after a Brit passenger reportedly caused chaos onboard.

The flight from Manchester is understood to have been disrupted when a 39-year-old man, who appeared to be drunk, shouted at passengers and staff.

Flyers faced hellish delays as their plane diverted to Thessaloniki Airport – roughly 750 miles from its final destination in the resort city of Antalya.

At the airport Greek police swiftly arrested the Brit and charged him with disturbance of order and dangerous interference with the aircraft.

The flight then continued on its path to sunny Antalya – dubbed the riviera of Turkey.

And another flight was forced to turn around in June after security officials discovered a FitBit named “bomb” in a terror scare.

Source: thesun.co.uk