Incident Overview
On 15 June 2018 at 12:54 UTC, a serious airprox occurred near Knonau, Switzerland, between a Beechcraft 1900 (registration T-729) operated by the Swiss Air Force and an unregistered paraglider. The aircraft was on an instrument approach with a missed approach to Emmen military airfield (LSME) and in contact with the Emmen aerodrome control officer (ADCO). The paraglider pilot had no radio contact with ADCO and did not call after the event.
Encounter Details
The Beechcraft 1900 was established on the Instrument Landing System (ILS) for runway 22 at an altitude of 5000 ft AMSL when the crew sighted a bright yellow high-performance paraglider ahead and to the right, approximately 9 nautical miles from the runway threshold. The aircraft passed about 100 m laterally left and 50 m below the paraglider without executing an avoidance maneuver. The aircraft then continued its approach without further incident.
Detection and Communication
The Traffic Collision Avoidance System (TCAS II 7.1) of the Beechcraft did not alert on the paraglider, nor did the radar display of the air traffic controller show the paraglider. This indicates that the paraglider was either not equipped with a transponder or the transponder was not active. The paraglider pilot was in Terminal Control Area (TMA) sector 3 of Emmen without permission.
Analysis and Conclusions
The investigation determined that the serious incident was attributable to the paraglider pilot being present in the TMA without the knowledge of air traffic control, while the passenger aircraft was conducting a radar-guided approach to Emmen. The Swiss Transportation Safety Investigation Board (STSB) noted that similar dangerous approaches between paragliders and aircraft had been investigated previously. For instance, final report No. 2218 described a near-collision between a paraglider and two commercial aircraft in Zurich TMA. Additionally, investigation No. 2294 into a near-collision between a commercial aircraft and a hot air balloon led to safety recommendation No. 518, which urged the Federal Office of Civil Aviation (BAZL) to mandate transponders for all aircraft that could pose a hazard to large aircraft over Swiss territory. The STSB concluded that implementing this recommendation could have prevented the incident.
Investigation Closure
Based on Article 45 of the Ordinance on Safety Investigation of Civil Aviation Incidents, the STSB conducted a summary investigation and closed the case with this report, refraining from further inquiries.
Location and Time
- Location: Knonau, Canton of Zurich (coordinates: N 47° 13' 23", E 008° 26' 30")
- Date and Time: 15 June 2018, 12:54 UTC (local time UTC+2)
- Altitude: approximately 1524 m AMSL
- Airspace: Terminal Control Area (TMA) sector 3 of Emmen