Misunderstanding Air Traffic Control instructions lead to a near-miss between A Royal Air Force tanker and two US F-15 fighters over the North Sea.
The pilots of the RAF Voyager said that one of the United States Air Force jets was as near as 160ft (50 metres) when it flew directly across their path. The tanker pilot said that they were flying at 322mph.
The F-15 flying at 402mph was close that the tanker crew could feel the turbulence as it switched on its afterburner and moved away to avoid a crash, The Telegraph reported Sunday.
One of the pilots of the tanker swiftly reported the near-miss to flight controllers, saying he and his crew "were very close to not being there anymore".
A report by the UK Airprox Board, which investigates near misses, concluded that the F-15s had been flown "into conflict" with the Voyager. Further, the report also said it happened as the air traffic controllers failed to provide adequate "traffic information".
One controller based at Stanwick, Hampshire, was said to have been confused when the F-15s stated that they would be flying in the Wash area and assumed they meant the geographic Wash. But the F15 crews meant they were flying into the so-called Wash Aerial Tactics Area which extended further north into the refuelling zone where the RAF tanker was flying.
The controller had assumed the F-15s would be flying safely further south. Then, he answered a landline phone which was not his responsibility. The call "served to further increase his workload and resulted in him focusing on an that task rather than on the F15s".
A trainee air traffic controller who was also monitoring the airspace said the F-15s had suddenly turned towards the Voyager and the incident "escalated rapidly", leaving her no time to order the tanker to take avoiding action.
The near miss happened on January 5 this year at a height of 16,000ft around ten miles off the coast of north Norfolk after the Voyage from RAF Brize Norton had refuelled two RAF Typhoons in mid-air.
The Voyager which is the size of airline jet, has a crew of eight and two pilots was flying west with its wing hoses still trailing when it received an alert about two approaching aircraft.
Investigators said they were "disappointed" that the American pilots had not been told in a pre-flight briefing that refuelling was taking place in the area where they were to be flying. As a result, the F-15s entered the refuelling area off the Norfolk coast, one of 14 such areas in the UK, without realising that it was "active".
An RAF investigation also said that the air traffic controllers "did not effectively prevent the F15 from entering the airspace around the Voyager". The report made 15 recommendations to prevent similar near misses, including a review of airspace names.