A British Airways flight experienced a significant change in altitude shortly after taking off from London Heathrow Airport to Chicago. The Boeing 777, heading to the U.S., descended about 27,000 feet, reaching around 9,000 feet altitude due to a technical issue.

A British Airways spokesperson confirmed that the aircraft returned to Heathrow following this issue, stating, “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.”

FlightAware, a flight-tracking website, indicated the plane turned back toward London but continued flying for several hours, circling above England before safely landing at Heathrow.

“They did everything by the book,” said Matthew “Whiz” Buckley, a retired U.S. Navy F/A-18 fighter pilot, noting that lowering the plane below 10,000 feet would remove the need for supplemental oxygen in case of a cabin pressure loss.

The rapid descent can be unsettling for passengers, particularly if it involves deploying oxygen masks. For some passengers accustomed to routine flights, this experience could feel akin to a “roller-coaster ride.”

The plane’s continued circling raised questions about why an immediate landing was not feasible. Buckley explained that a transatlantic flight carries substantial fuel, and reducing weight is necessary before landing. If fuel cannot be dumped, the plane must burn fuel mid-flight to reach a safe landing weight.

“You cannot land heavy,” Buckley said, due to the potential strain on landing gear and brakes. Pilots must evaluate the aircraft’s situation and choose the safest approach for landing, ensuring no further emergencies develop.

Kelly McGreal, working with the lifestyle team at Fox News Digital, contributed to this report.