A British Airways plane travelling from Washington Dulles airport was involved in a “full emergency” before landing safely at Heathrow airport.
The incident briefly closed the airport’s south runway, causing delays to other flights.
It follows the emergency evacuation of a BA plane at Las Vegas airport earlier this week due to an engine fire.
The Boeing 777 flight landed at 10:38 BST after suffering a “technical issue”.
A Heathrow Airport spokesman said: “It was a full emergency but it’s all clear.
“The flight crew requested a priority landing as a precaution, and the aircraft landed safely.
“All the runways are open. The aircraft has been pulled back to its stand. It’s just a technical issue.
“Our engineers are inspecting the aircraft to determine what the issue was.”