A LIGHT aircraft towing a glider came within 50ft of colliding with another glider close to the North's most popular club dedicated to the sport, an inquiry has concluded.

The UK Airprox Board, which investigates mid-air near misses, found the Discuss, Astir and Eurofox aircraft were in such close proximity at about 2,500ft, two miles east of Sutton Bank, near Thirsk, that the safety of the aircraft may have been compromised.

The near-miss happened near the base of the Yorkshire Gliding Club, whose members have included pioneering aviator Amy Johnson and where there are almost 5,000 flights annually, in what is among the busiest aviation areas in the country.

The club's leaders say safety is taken extremely seriously and that it works with numerous organisations to lessen risks.

A report into the incident on February 24, at 2.55pm, states the Discuss glider pilot had been flying along a cloud-street - a long roll of counter-rotating air - when his Flarm collision avoidance system was triggered, indicating traffic behind him.

The report states: "The Flarm alerted again and, very shortly afterwards, he saw a tug and glider combination to his right at the same altitude. He turned left to increase separation. The other glider pilot subsequently stated that he had passed very close below the Discus. He assessed the risk of collision as very high."

The pilot of the Eurofox light aircraft, who rated the risk of a collision as medium, said he had seen the Discus at a range of about 200ft, slightly higher and on a shallow converging course, so he turned right at a rate that the Astir glider he was towing could follow and move the aircraft clear of the Discus.

The Astir glider pilot said he had spotted the Discus and that he and the Eurofox had executed a reasonably tight right turn to avoid any conflict with the other glider. He assessed the risk of collision as low.

After discussing the incident at length, the three pilots decided to report it to the UK Airprox board to increase awareness of potential risks within the gliding community.

The report states: "Board members debated the fact that glider pilots regularly operated in close proximity to each other,

especially when thermaling [using rising currents of warm air], and there was a concern that the gliding community may have allowed themselves to become normalised to a significant mid-air collision risk without an explicit assessment."

The board found the incident had been caused by a mutual late sighting by the Discus and Eurofox pilots.