About an hour after leaving London Gatwick on Tuesday morning, somewhere past Brittany, the crew of British Airways flight BA2660 to Faro turned their Airbus A321 around. A passenger window on the right-hand side of the cabin, near row 3, had been reported as cracked.

The crew set the transponder to 7700, the general emergency code, and flew back to Gatwick, where emergency services were waiting. The aircraft landed safely. British Airways described the cause as a minor technical issue and did not confirm the window damage.

It sounds dramatic, and for the passengers in row 3 it surely felt that way. But a cracked cabin window is one of those incidents that airliners are designed to survive, which is exactly why the crew had time to fly home.

Ce qui s'est passé

BA2660 left Gatwick at 9:06am. According to flight-tracking reports cited by AirLive and Aviation24.be, the crew reported structural damage to a window panel on the right side of the cabin, near row 3R, and declared an emergency while assessing the window and deciding where to go. They chose to return to London rather than continue to Portugal or divert into France.

AirLive reported that cabin pressure was maintained throughout. Emergency crews met the aircraft at Gatwick, as is usual after an emergency declaration.

The airline added that it had apologised to customers for the delay and was working to get their travel plans back on track. It did not say which part of the window had cracked.

Why a Cracked Window Is Not a Disaster

An airliner cabin window is not one pane of glass but a stack. On most modern jets there is an outer pane that carries the pressure load, a middle pane that can take over if the outer one fails, and a thin inner pane that simply protects the others from passengers' elbows and scratches. The tiny hole you see in the window, the breather hole, keeps the pressure between the panes balanced so that the outer pane does the work.

That design means a crack in one layer usually leaves the aircraft with pressure intact, as appears to have happened here. Crews still treat it seriously: a damaged pane is a weakened pane, and nobody wants to test the backup over the Bay of Biscay. Turning back with a healthy aircraft and a weakened window is precisely what the procedures are for.

Engineers will now inspect G-EUXD to find out which pane was damaged and why. Until they report, the details remain unconfirmed.

Zack D. Films explains the tiny breather hole in airliner windows, part of the multi-pane design that lets a cracked window stay safe.

Sources: AirLive; Aviation24.be; Eastern Eye (British Airways statement).