RAF Typhoon aircraft were launched to intercept a civilian aeroplane and escort it to Stansted airport after it caused concern to air traffic controllers.

The aircraft, a Soviet-era Antonov An-26 cargo plane, owned by the Latvian company RAF-Avia was safely escorted down by the military jets from RAF Coningsby – which broke the sound barrier in the process.

RAF-Avia said the plane was on its way to Birmingham airport and had been carrying automotive parts. It had taken off at 11am from Toscara in Italy, before landing in Vatry in France and then continuing its journey to the UK. It was due to land in Birmingham late afternoon on Friday. For unexplained reasons, it didn’t make it.

“It’s definitely our plane. Most probably there has been some kind of malfunction or some emergency situation,” a spokeswoman – who declined to be named – said, speaking from the firm’s head office in the Latvian capital Riga. “We don’t know exactly what happened.”

The company said its fleet of ageing Antonovs typically transported car parts and other cargo for assembly plants across Europe. This was the first time it had been involved in an emergency incident, it said.

The noise of the two Typhoons breaking the sound barrier in their pursuit had caused a stir over Kent as residents heard the noise and thought an explosion had occurred. London Fire Brigade were put on alert before the true reason for the noise was discovered.

The blast was heard at about 4.40pm coming from the Dartford area and was also felt in Sevenoaks, Kemsing, Dartford, Faversham, Maidstone and Tunbridge Wells, according to posts on Twitter.

An RAF spokesman said: “Typhoon aircraft were launched this afternoon from RAF Coningsby to intercept a civilian aircraft south of London which was causing concern to air traffic control authorities.

“The aircraft was safely escorted to London Stansted.

“To fulfil their quick reaction role the Typhoons were cleared to travel at supersonic speed, any noise disturbance as a result of this is regretted. Essex police now have the lead.”

Typhoons launched to intercept a civil aircraft. It was safely escorted to Stansted. Our aircraft cleared supersonic during the scramble. — Royal Air Force (@RoyalAirForceUK) October 29, 2014

The RAF said on Twitter: “Typhoons launched to intercept a civil aircraft. It was safely escorted to Stansted. Our aircraft cleared supersonic during the scramble.

“Apologies if we startled you during the successful intercept this afternoon - we only go supersonic over land when absolutely necessary.”

A spokesman for Stansted airport said they believed that contact with the plane had been lost by air traffic controllers. The plane landed at 5.15pm at Stansted where police surrounded and checked it, as is standard procedure.

The all-clear was given at 5.42pm and the plane will continue to Birmingham, he said.

• This article was amended on 31 October 2014 to correct the description of the civilian plane.

