What happened
On June 24, 2020, a single-engine Robin DR-400, registration HB-KFQ, departed from Sion airport for a flight toward Thun. While navigating via aeronautical charts using terrestrial landmarks, the pilot entered the Meiringen Terminal Control Area (TMA) without realizing it. At approximately 10:56 AM, the pilot contacted the Meiringen tower to request permission to cross the control zone via the north side of the valley. At that moment, the pilot believed they were south of Guttannen, but they were actually north of the village near Innertkirchen.
Simultaneously, several Boeing F/A-18 fighter jets had recently departed from Meiringen airfield. The air traffic controller, unaware that the HB-KFQ had already entered the TMA due to a lack of radar coverage, instructed the light aircraft to hold over Guttannen. Shortly after this instruction, one of the departing fighter jets encountered the light aircraft. The fighter pilot spotted the Robin DR-400 at roughly 7,000 feet and initiated a downward evasive maneuver approximately five seconds before the closest point of approach. The minimum distance between the two aircraft was estimated at approximately 50 m.
The investigation
The investigation by SUST relied on crew statements, radio communications, and available ground radar data, though radar coverage was noted as incomplete during the event. The investigation established that the pilot of the HB-KFQ did not perceive the close encounter or the fighter's evasive maneuver. Instead, the pilot observed the fighter jets turning left and interpreted this as part of their standard departure route. The controller's inability to track the light aircraft was attributed to a lack of radar coverage for that specific area.
Findings
- The primary cause of the near-collision was the inaccurate position determination by the pilot of the HB-KFQ, which led to an unintended airspace infringement.
- The pilot was using terrestrial navigation, which resulted in a discrepancy where the pilot believed they were south of Guttannen while actually being inside the TMA.
- The air traffic controller was unaware of the light aircraft's presence within the TMA because the aircraft's transponder was not captured by ground radar.
- The pilot of the Boeing F/A-18 successfully identified the hazard and performed an evasive maneuver to prevent a collision.