Sonic booms heard as RAF scrambles Typhoons
Loud bangs heard in parts of Yorkshire were sonic booms from Typhoon jets scrambled to identify "an unresponsive civilian aircraft", the RAF has said.
The aircraft were launched from RAF Coningsby, in Lincolnshire, on Monday and helped guide an Air France plane to a safe landing in Newcastle.
People reported their houses shaking at about 21:50 BST after hearing what sounded like two loud explosions.
These were later confirmed to have been sonic booms.
An RAF spokesman said on Monday night: "Quick reaction alert Typhoon aircraft were launched today from RAF Coningsby to identify an unresponsive civilian aircraft.
"Communications were re-established and the aircraft has been safely landed."
Reports suggested the jets had escorted the plane after it went off course.
Air France confirmed that the unresponsive civilian aircraft was one of its planes.
The airline tweeted from its official UK Twitter account: "Air France confirms that due to a radio communication problem AF 1558 had to be accompanied by two British fighter aircrafts according to the procedure.
"The aircraft landed in Newcastle at 22:20 (LT). Safety of clients & crew is an absolute priority."
North Yorkshire Police had tweeted to reassure people there was no danger, later writing: "Confirmation from RAF that loud bangs heard across the county were sonic booms from RAF Typhoon jets. No cause for concern."
One woman wrote: "house shook & whole street was out, car & house alarms gone off. Apparently was a sonic boom".
What is a sonic boom?
A sonic boom is created as an aircraft breaks the sound barrier, causing a high-energy shockwave.
When an aircraft approaches the speed of sound, the air in front of the nose builds up a pressure front because it has "nowhere to escape", Dr Jim Wild of Lancaster University said.
It can be heard over a large area because "it moves with the plane", similar to the wake on the bow of a ship spreading out behind the vessel, Dr Wild added.
Reacting on social media, initial concern moved to light-hearted responses after the cause of the loud bangs became clear.
Former Leeds United goalkeeper Nigel Martyn tweeted: "Huge bangs that shook the doors at our house, must have been the Leicester fans celebrating the Premier league!!"
Another Twitter user posted: "I like to think this is a test run for how Yorkshire would react to a nuclear war. My neighbour made everyone Ovaltine."