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ASN Wikibase Occurrence # 200707
Last updated: 19 March 2020
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Time:14:42 LT
Type:Silhouette image of generic arcu model; specific model in this crash may look slightly different
Schempp-Hirth Arcus
Owner/operator:Segelfluggruppe Cumulus
Registration: HB-3442
C/n / msn: 18
Fatalities:Fatalities: 0 / Occupants: 1
Other fatalities:0
Aircraft damage: None
Location:SW of Amriswil, TG -   Switzerland
Phase: En route
Departure airport:Amlikon Airport (LSPA)
Destination airport:Amlikon Airport (LSPA)
Investigating agency: STSB Switzerland
A Schempp-Hirth Arcus glider (HB-3442), was gliding back to Amlikon Airfield, Switzerland. The gliderís Flarm collision warning device was switched on; however, its Mode S transponder was not. At approximately the same time, a Falcon 2000EX corporate jet aircraft (CS-DLB), was flying from Munich Airport in Germany to St. Gallen-Altenrhein, Switzerland. CS-DLB was equipped with a Traffic Alert and Collision Avoidance System (TCAS).
Under supervision of the Zurich ARFA approach control unit, CS-DLB was approaching the Instrument Landing System (ILS) of runway 10 at St. Gallen-Altenrhein. Flying the base leg at an altitude of 5,000 ft AMSL and in Class E airspace, the flight paths of CS-DLB and HB-3442 crossed in opposite directions. The closest horizontal and vertical distances between the two aircraft were approximately 660 m and 40 m respectively. Both crews only noticed the other aircraft shortly before the point of closest proximity. The air traffic controllers, who the crew of CS-DLB were in contact with, were unaware of the glider.

The serious incident was an airprox between a twin-jet business aircraft and a glider, which can be attributed to the fact that the two flight crews did not visually identify each otherís aircraft in a timely manner.
The following factors were identified as contributing factors:
- The instrument approach of the business aircraft led through Class E airspace, in which air traffic control does not provide separation between IFR and VFR traffic.
- The transponder of the glider was not switched on, which was not mandatory. The fact that the glider pilot did not have radio contact with the relevant air traffic control unit, which is not mandatory either, favoured the development of the serious incident.


Accident investigation:
Investigating agency: STSB Switzerland
Status: Investigation completed
Duration: 1 year and 10 months
Download report: Final report


Source: STSB

Revision history:

30-Oct-2017 10:12 harro Added
08-Sep-2019 16:38 harro Updated [Departure airport, Destination airport, Narrative, Accident report, ]

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