Houses shook in Yorkshire amid loud bangs as Typhoon jets were scrambled to an Air France passenger plane with a radio communication problem.
The aircraft were launched from RAF Coningsby on Monday night to identify an unresponsive civilian aircraft, the Ministry of Defence said.
People reported hearing what sounded like two loud explosions which were later confirmed to have been sonic booms.
Air France confirmed that the unresponsive plane had been one of their aircraft but it later landed safely guided by the Typhoon jets.
An RAF spokesman said: “Quick reaction alert Typhoon aircraft were launched from RAF Coningsby to identify an unresponsive civilian aircraft. Communications were re-established and the aircraft has been safely landed.”
Air France tweeted from its official UK Twitter account that a radio communication problem caused the jets to scramble.
The message over two tweets said: “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 and South Yorkshire Police earlier 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.”
Another said: “Those vibrations shook my house and scared me to death. #QRATYPHOON had me out of my bed.”
Some reports suggested the plane had flown off course while other said it had lost radio contact for more than seven minutes. Refuelling aircraft from Brize Norton are also understood to have been brought in to back up the operation.
Last month, two bangs heard around Northampton and Brackley were caused by Typhoon jets which had been scrambled from an RAF base in Lincolnshire to identify an unresponsive aircraft.
WHAT IS A SONIC BOOM?
A sonic boom is the sound associated with the shock waves created by an object travelling through the air faster than the speed of sound. Sonic booms generate enormous amounts of sound energy, sounding much like an explosion.
When an aircraft passes through the air it creates a series of pressure waves in front of it and behind it, similar to the bow and stern waves created by a boat. These waves travel at the speed of sound, and as the speed of the object increases, the waves are forced together, or compressed, because they cannot get out of the way of each other. Eventually they merge into a single shock wave, which travels at the speed of sound, a critical speed known as Mach 1, and is approximately 1,225 km/h (761 mph) at sea level and 20 °C (68 °F).