Air Canada said the Boeing 767-300 — which is carrying 128 passengers and took off Monday afternoon — experienced an “engine issue” shortly after takeoff.
The Canadian flag carrier said flight AK837 is currently circling around Madrid “to use up fuel and lighten the aircraft for landing.”
“A tire also reportedly ruptured on take-off,” Air Canada said in a statement, adding that the tire is “one of 10” on the plane.
“The aircraft, a Boeing 767-300, is designed to operate on one engine and our pilots are fully trained for this eventuality. Nonetheless, an emergency was declared in order to obtain landing priority,” it said.
The airport’s operator Aena said on Twitter that the Barajas was “prepared to receive” the flight destined for Toronto.
Firefighters have been deployed as a preventative measure, according to the Twitter account of the regional government-run emergency service.
In 2018, a drone incursion at London’s Gatwick Airport caused travel chaos for tens of thousands of passengers.
Despite a wide-ranging operation and a £50,000 (about $65,500) reward, authorities have still been unable to find the person behind the drone attack.