An RAF Chinook flying at 90mph was less than a second away from crashing into a model plane.
An official report by the UK Airprox Board has revealed that the helicopter was coming in to land at a height of 400 feet at RAF Benson, Oxfordshire, when one of the crew spotted a light blue remote-controlled aircraft 80ft away.
The Ministry of Defence's Joint Helicopter Command said crews had been warned to be 'extra vigilant' due to the threat of collisions with drones and model planes being 'on the increase.' It added:
'It is disconcerting that there has been a significant increase in incidents in the vicinity of our airfields and that certain... operators do not seem to be taking into consideration the safety of other air users when conducting their flights.'
It said that the £60 million helicopter had been 'endangered' by the model, which could have 'compromised' its safety.
The risk of collision was rated as 'medium', although the pilot was ultimately able to land safely.
The report stated that the model aircraft operator, who a crew member believed he saw on a nearby road, had shown 'disregard' for the Chinook's safety.
It added that the person, who has not yet been traced, was 'ill-advised' to be flying in the area due to the number of helicopters landing and taking off from the base, although they were 'by far the exception from the majority of model aircraft operators who were invariably responsible in their activities.'
Cover photo a file image of an RAF Chinook.