LONDON — A British Airways passenger jet declared an emergency and descended 27,000 feet while flying from London to Chicago on Monday.
About 30 minutes into its journey, the Boeing 777 dropped from 36,000 feet to 9,000 feet in around seven minutes, according to flight tracking website FlightAware.
The plane turned around over Ireland before zig-zagging over the Bristol Channel to the west on England for the next four hours, finally landing back at London’s Heathrow Airport at 5 p.m. local time (noon ET).
British Airways and Heathrow did not immediately respond to requests for comment.
This is a developing story. Please check back for updates.

