Overview
On May 15, 2019, at 12:01:57 local time, a serious incident occurred 2 km southwest of Altendorf, Switzerland, involving a Mooney M20J aircraft (registration HB-DIH) and a formation of two Swiss Air Force F/A-18 fighter jets (registrations J-5236 and J-5025, call signs Rookie71 and Rookie72). The minimum separation between the aircraft was approximately 100 meters horizontally and 15 meters vertically. The incident was classified as an ICAO Airprox category A, indicating a significant collision risk.
Incident Details
The Mooney M20J, a single-engine, four-seat aircraft operated by ASFG Ausserschwyzer Fluggemeinschaft Wangen, was on a Visual Flight Rules (VFR) training flight from Memmingen Airport (EDJA) to Wangen-Lachen Airport (LSPV). While descending for landing at approximately 2000 feet above ground, the aircraft encountered the two F/A-18 jets, which were also flying under VFR as a military formation from Payerne Air Base (LSMP). The encounter occurred at an altitude of about 4000 feet AMSL near the boundary between Class G and E airspace. No prescribed separation minima applied in this airspace.
Aircraft and Crew Information
The Mooney M20J, manufactured by Mooney Aircraft Corporation, was equipped with a satellite navigation system (GPS) and a transponder, but no collision warning system (such as TCAS) was installed according to the report. The pilot was a private pilot undergoing training. The F/A-18 jets, manufactured by Boeing, were operated by the Swiss Air Force. Each fighter was crewed by a single pilot. The military aircraft were equipped with transponders and radar, but their collision avoidance systems were not specified in the report.
Causes
The Swiss Transportation Safety Investigation Board (STSB) determined that the serious incident resulted from insufficient perception of the approaching fighter jet formation by the pilot of the motorized aircraft and delayed perception of the motorized aircraft by the crews of the fighter jets. No other causal factors were identified.
Safety Recommendations
The STSB issued no safety recommendations but provided a safety notice regarding fighter jets operating in Class G and E airspace. After the incident, the Swiss Air Force implemented measures to improve situational awareness, including the use of transponders and communication procedures in such airspace.
Previous Similar Incidents
The report referenced several similar near-collision events in Swiss airspace involving fighter jets and civil aircraft, including a glider (HB-3401) and two F/A-18s, a helicopter (HB-ZAN) and two F/A-18s, and others, highlighting recurring challenges in see-and-avoid encounters with high-speed military aircraft.