BA295 drops 28,000 feet over Ireland and returns to Heathrow

British Airways flight BA295 left London Heathrow for Chicago O'Hare at 12.14pm on Monday and was back on the ground at Heathrow at 5.03pm, after a descent of about 28,000 feet over Ireland and a general emergency call to air traffic control. The aircraft was a Boeing 777-200ER. No injuries were reported. Passengers left the aircraft in the normal way.

About an hour after departure the jet was at its cruise altitude of 37,000 feet. Flight-tracking data showed it then drop to about 9,000 feet within minutes and turn back east of Ireland. The crew set the transponder to 7700, the international code for a general emergency. A rapid descent toward 10,000 feet is the standard first response to a suspected loss of cabin pressure, because supplemental oxygen for passengers is certified for a short period and the air at 10,000 feet is breathable without masks. British Airways has not confirmed that the event was a depressurisation. It has called it a technical issue.

What passengers described

Passenger Tom Nicholls told the Mirror and, in a separate account carried by The Guardian, that the aircraft hit a sudden patch of turbulence, that oxygen masks dropped from the ceiling, and that the descent to 9,000 feet did not feel as violent as the tracking plot suggested. He said the pilots adjusted the path and that a couple seated ahead of him could not reach their masks at first. By the time they had moved to spare seats with working masks, the captain had announced that the aircraft was below 10,000 feet and that the masks were no longer needed.

Masks deploying does not, by itself, prove a hole in the fuselage. They can drop because cabin altitude rises above a set threshold, because of a sensor fault, or because the crew commands them. The useful public fact is the combination: masks, a 7700 code, and a descent from 37,000 to about 9,000 feet, followed by a fuel-burn hold rather than an immediate overweight landing.

Why the jet circled the Bristol Channel

A 777-200ER leaving Heathrow for a nine-hour sector to Chicago carries far more fuel than it needs for a return to London an hour into the flight. Landing above maximum landing weight risks hot brakes, long stopping distances and structural loads the crew would rather avoid if they have time. Tracking services showed BA295 flying a looping hold over the Bristol Channel, between Pembrokeshire and the north Devon coast, while it burnt fuel. It then landed at Heathrow just after 5pm. The Independent, citing FlightAware, put the landing at 5.03pm and the total airborne time at 5 hours and 13 minutes.

A British Airways spokesperson said the safety of customers and crew was the priority, that the aircraft landed safely after highly trained pilots returned to Heathrow following a technical issue, and that customers disembarked normally while teams worked to restart their journeys. The airline did not name the system that failed. It did not say whether the same airframe was back in service on Tuesday.

What the numbers imply

The scheduled block time to O'Hare is about nine hours. The jet used a little over five hours to go out, descend, hold and return. The diversion point, roughly over Ireland, is consistent with a decision made early enough that Shannon or another Irish field was available and was not used. Crews in a pressurisation emergency will take the nearest suitable airport if the aircraft cannot hold a safe cabin altitude. A return to Heathrow after a controlled descent and a long fuel burn suggests the crew judged the aircraft stable at the lower altitude and preferred the home base, where British Airways has engineering, spare aircraft and passenger handling.

That judgment is the part passengers cannot see from a mask hanging in the aisle. The public record on Tuesday is the track, the 7700 code, the mask reports, the 5.03pm landing, and an airline statement that stops at "technical issue." Investigators will want the cabin-altitude trace, the outflow-valve position and the crew's technical log. None of those has been released.