What happened
On May 6, 2018, at approximately 16:32 local time, a serious airprox incident occurred in the airspace near Innertkirchen, Switzerland. The event involved two aircraft operating under Visual Flight Rules (VFR) for private purposes.
The first aircraft, a DH-115 MK.55 with registration HB-RVJ, departed from St. Gallen-Altenrhein (LSZR) and was en route to St. Stephan (LSTS). The second aircraft, a Gulfstream American Corporation AA-5B registered as HB-UCM, was performing a flight originating from and returning to Kägiswil (LSPG).
The investigation
The Swiss Transportation Safety Investigation Board (SUST) has opened an investigation into the near-collision between the former Swiss Air Force fighter and the light motor aircraft. As this is a preliminary report, the investigation is ongoing to determine the full circumstances surrounding the encounter.