- BA295 dropped from about 37,000 feet to 9,000 feet over Ireland.
- Oxygen masks deployed after the aircraft experienced a technical issue.
- The Boeing 777-200ER circled before safely landing back at Heathrow.
A British Airways flight from London to Chicago was forced to turn back after making a sudden descent of around 28,000 feet over Ireland.
Flight BA295 was about an hour into its transatlantic journey from London Heathrow to Chicago O’Hare when the Boeing 777-200ER descended from its cruising altitude of around 37,000 feet to approximately 9,000 feet.
The aircraft also issued a 7700 emergency squawk, the internationally recognised code used to alert air traffic control that a plane is experiencing a general emergency.
Passengers said oxygen masks dropped from the ceiling following turbulence, although British Airways has not confirmed that the aircraft experienced a loss of cabin pressure.
Passenger Tom Nicholls described a “sudden bit of turbulence” before the emergency.
“The plane adjusted but it didn’t feel like it was descending rapidly. I’d say the pilots did a very good job,” he said.
“The oxygen masks popped out soon after and there was a bit of uncertainty onboard.”
The captain later told passengers the aircraft was below 10,000 feet and the masks were no longer needed.
What is the 7700 emergency code?
7700 is a general emergency signal used by pilots to alert air traffic control that an aircraft needs assistance. It does not tell controllers exactly what has gone wrong.
The code can be used for a range of emergencies, including technical problems, medical situations, severe weather or other circumstances requiring urgent assistance. Controllers then communicate with the crew to establish what is happening and what support is required.
In BA295’s case, flight-tracking data showed the aircraft transmitting the 7700 code while flying over Ireland before descending to around 9,000 feet.
British Airways has so far described the cause only as a “technical issue”. The airline has not confirmed that the incident was caused by cabin depressurisation.
A rapid descent to below 10,000 feet is commonly associated with a suspected pressurisation problem because the air at lower altitude is dense enough for people to breathe without relying on supplementary oxygen. But in this case, that remains an inference rather than a confirmed cause.
Why did the London-Chicago flight turn back?
After the emergency descent, BA295 reversed course towards Britain instead of continuing across the Atlantic.
Flight-tracking data showed the aircraft subsequently flying holding patterns over the Bristol Channel as it reduced its fuel load before landing. Long-haul aircraft carry substantial amounts of fuel for transatlantic journeys, so a plane returning relatively early can be significantly heavier than it would normally be when landing.
The aircraft eventually landed safely at Heathrow shortly after 5pm, several hours after leaving London.
British Airways 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.”
Photographs shared by passengers showed oxygen masks hanging from the aircraft's ceiling.
There were no immediate reports of serious injuries, and many passengers were booked on alternative flights departing on Tuesday.
The aircraft involved was a Boeing 777-200ER, registered as G-VIIA. It was delivered to British Airways in July 1997 and is one of the airline's older aircraft.
For the passengers on BA295, what began as a routine London-Chicago journey instead ended with an emergency descent, a U-turn over the Atlantic and a return to Heathrow.
British Airways has not yet provided further details about the technical problem.
