Airprox at Bern Belp Airport Involving HB-SRB and HB-ZIE

Incident Overview and Location On the evening of 21 November 2016, a serious incident occurred at Bern Belp Airport (LSZB) in Class D airspace. The event involved two aircraft conducting night training operations under Visual Flight Rules (VFR). The closest horizontal proximity between the aircraft was approximately 300 m, classified as an ICAO category B airprox. The incident took place at an altitude of approximately 1,700 ft above mean sea level. ## Aircraft and Crews The first aircraft was an AT-3 R100 registered as HB-SRB, operated and owned by Alp-Aircraft GmbH. It was on a training flight with a pilot and a flight instructor aboard. The pilot held a Private Pilot Licence Aeroplane (PPL(A)) and had 79:30 total hours, including 77:00 hours on the incident type. The flight instructor held an Airline Transport Pilot Licence aeroplane (ATPL(A)) with 24,700 total hours. The second aircraft was an EC120 B helicopter registered as HB-ZIE, operated and owned by Swiss Helicopter AG. It was also on a training flight with a pilot and a flight instructor. The pilot held a Private Pilot Licence Helicopter (PPL(H)) with 395:15 total hours, while the flight instructor held a Commercial Pilot Licence Helicopter (CPL(H)) with 3,550 total hours. ## Sequence of Events The helicopter crew departed from near Düdingen, canton of Fribourg, and requested entry into the control zone via waypoint W1 for an approach to runway 14. The fixed-wing aircraft was conducting solo circuits on the same runway. At 18:03:00 UTC, the air traffic controller informed the HB-SRB pilot that he was number two behind the helicopter on a long final approach. The helicopter crew later indicated they did not intend to make a full stop landing but would proceed directly to the Swiss Helicopter base south of the runway 14 threshold. At 18:05:21 UTC, the controller cleared HB-SRB for a touch-and-go, assuming the pilot could assess the situation. The HB-SRB pilot read back the clearance as a landing clearance. During the final approach, the HB-SRB flight instructor instructed a go-around at 18:06:16 UTC when the aircraft was approximately 400 m behind the helicopter. By 18:06:31 UTC, the helicopter had left the runway, and the aircraft passed over it at a vertical distance of approximately 15 m. ## Weather and Investigation Findings Weather conditions were dry with visibility of more than 10 km, variable winds at 3 kt, and a temperature of 6°C. The investigation noted that due to limited radar coverage and incomplete GPS data, it was not possible to accurately determine the exact horizontal and vertical distances at the moment of closest proximity. The air traffic controller stated he could not assess the proximity from the tower due to darkness and distance.