Air ambulance and small plane narrowly avoid crash

The East Anglian Air Ambulance's Anglia Two helicopter was involved in a near-miss in Hertfordshire

An air ambulance and a small plane came close to crashing head-on after unknowingly flying too close to each other, an investigation has found.

They were flying in what is often "congested" airspace above Buntingford in Hertfordshire just before 16:00 GMT on 20 March when the near-miss occurred.

The pilot of the East Anglian Air Ambulance, a H145 Airbus helicopter, only became aware of the Sprite plane when it flew past, while the plane's pilot did not see the helicopter at all, the UK Airprox Board said.

It ruled there had been a "serious risk of collision" and rated the risk as Category A, which is the highest possible risk.

According to its report, the Anglia Two helicopter was flying from Cambridge towards Stevenage, initially on what was an emergency operational task.

But a few minutes later the pilot turned around and started to return to base at Cambridge Airport.

It was then that a white and blue two-seater fixed-wing aircraft reportedly "came sweeping in" about 100ft (30m) directly below the helicopter.

The pilot of the plane, which was carrying out a local solo flight, only became aware of the close-call the next day when the helicopter pilot phoned to inform them, the report said.

They told the Airprox panel they could not "understand why they had not seen the helicopter", adding that there was nothing obvious that could have distracted them.

The helicopter pilot, meanwhile, described the incident as a "non-sighting", and said they would not have had time to take any avoiding action.

According to the report, the Traffic Collision Avoidance System fitted to the helicopter would have been expected to have detected the transponder fitted to the plane, but no alert had been reported.

It was also noted that the Sprite had not been fitted with an additional traffic tracking device which, on this occasion, "may have provided a timely alert to the presence" of the helicopter.

The UK Airprox Board said both pilots perhaps could have requested a surveillance-based service, which enables them to broadcast their precise location, altitude and velocity.

The panel also said the safety of the aircraft had not been assured and the separation between the two had been "reduced much below the norm".

"Neither pilot had been able to have taken any action to have improved matters and providence had played a major part in events," the report said.

The board ruled neither pilot had demonstrated situational awareness and both had equal responsibility for the "serious risk of collision".