Two skydivers nearly collided in mid-air with a pair of fighter jets travelling at almost 350mph over the UK, a report has revealed.
The parachutists were free-falling at speeds of 120mph over Chatteris airfield in Cambridge when the US warplanes passed underneath them.
Details of the incident in April have been revealed in a report by the UK Airprox Board, which classified it in the second-highest danger category.
The air safety assessors said they had seen footage recorded on the helmet camera of one of the skydivers and could “clearly see” the F15 jets passing beneath.
The report said: “Once the parachutists had seen the F15s there was very little they could do to avoid the situation, having no control over their speed or direction whilst in free-fall.”
The report said it was “unfortunate” that the pilots from RAF Lakenheath in Suffolk had not received any warnings from air traffic control that the parachute site was active.
This was because the jets had been handed over from air traffic controllers at RAF Coningsby in Lincolnshire to those at RAF Lakenheath “at a busy time”, according to the report.
“As they overflew the drop site, it was unlikely that the pilots would have been able to see the parachutists and take avoiding action, and in this case they were unaware that they had flown beneath them,” the UK Airprox Board said.
It was difficult to work out the actual distance between the jets and the parachutists “because of lack of information”, the board added.
The pilots should have known about the position and activities of Chatteris airfield and should have asked air traffic control if it was active before flying over it or avoided the airfield, the UK Airprox Board said.
Crews at RAF Lakenheath have since been re-briefed about the airfield, according to the report.
The board stated that operators at Chatteris airfield call nearby air traffic controllers each morning to tell them if they are active, and the dropping aircraft also alerts them.
The report said there was “very little more that Chatteris could have done”.
The risk was assessed by the UK Airprox Board as Category B, meaning “safety had been reduced much below the norm”.