UK Airprox Board details two near miss incidents involving drones

In it’s monthly report of February 2015, the UK Airprox Board (UKAB) details two near-miss incidents involving quadcopter drones and a helicopter and paraglider.

On September 30, 2014 the pilot of an AgustaWestland AW139 helicopter reported flying an ILS approach into Norwich and was just above the Rackheath Industrial estate at 1000 feet when the crew saw a UAV very close to the aircraft. Although it was difficult to judge distance due to not knowing the actual size of the drone, the crew estimated that it was level with their aircraft, in the 10 o’clock position and 50m away, almost perfectly on the ILS glideslope. The incident happened very quickly but, from the brief glimpse they had of the UAV, it was a type of quadcopter with rotors on the corners. They immediately broke off
the ILS and continued with a visual approach.

In determining the cause of the Airprox, the Board agreed that the quadcopter had been flown into conflict with the AW139, and that a contributory factor had been that the Quadcopter had been flown in the Norwich approach path. The Board noted the AW139’s estimate of proximity, and that he had to manoeuvre to avoid the quadcopter; they therefore assessed the risk as Category B, safety margins had been much reduced below the normal.

The second incident occurred on October 2, 2014. A paraglider reported that he was ridge-soaring near Rushup Edge in a purple and white paraglider. The pilot was operating under VFR in VMC in ‘strong winds’ and therefore relatively high, at about 150ft. He saw a ‘DJI Phantom FC40 type’ quadcopter drone descend to about 20ft above his canopy. He noted it was quite hard to see against the grey sky, even with a row of green and orange LEDs on the underside. The pilot reported that he couldn’t see anyone on the ridge or in the fields below ‘with a radio unit’ and assumed the quadcopter had a camera and was being flown out of line of vision using a remote screen to monitor the ‘view’ from the drone. He stated that each time he changed direction the quadcopter tracked the change and followed him, with about 25ft vertical separation and between zero and 25ft horizontal separation. Whilst quite interesting to watch, and remarkably stable in strong winds, the hazard of a collision with his thin canopy-to-harness lines caused serious concern. The quadcopter flew close on a number of occasions and, he suspected, was taking video footage of his paraglider with an onboard camera. It flew at estimated heights of between 150ft and much higher, to the point of barely being visible. The paraglider pilot flew the length of the ridge a couple of times, looking for someone with a remote control transmitter, but couldn’t see anyone. He stated that some time after landing, another pilot told him they had seen the quadcopter fly down to the road where it was landed and loaded into a car. He opined that the quadcopter operator may have piloted the craft from inside the car.

The UKAB Board Members unanimously agreed that it was clear that the quadcopter had been flown into conflict with the paraglider. They considered that the lack of available control of the quadcopter, and the inability of its operator to properly perceive closing distances and rates, meant that chance had played a major part in events and safety had been very much reduced below acceptable levels; short of the paraglider pilot landing immediately, nothing more could have been done by him to improve matters given that the quadcopter operator seemed to have been deliberately following him in flight.