Serious incident Diamond DA42 Twin Star HB-SDM,
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ASN Wikibase Occurrence # 249279
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Date:Sunday 24 January 2021
Type:Silhouette image of generic DA42 model; specific model in this crash may look slightly different    
Diamond DA42 Twin Star
Owner/operator:Twin Star Aviation
Registration: HB-SDM
MSN: 42.039
Year of manufacture:2005
Fatalities:Fatalities: 0 / Occupants: 2
Aircraft damage: None
Category:Serious incident
Location:1 km NE of Sursee (LU) -   Switzerland
Phase: En route
Departure airport:Lausanne-La Blécherette Airfield (QLS/LSGL)
Destination airport:Birrfeld Airfield (LSZF)
Investigating agency: STSB
Confidence Rating: Accident investigation report completed and information captured
A Piper PA-28-181 (HB-PRM) and a Diamond DA 42 (HB-SDM) were involved in a serious airprox incident at 1900 m altitude.

The pilot of the PA-28 visually identified the oncoming aircraft shortly before the point of minimum separation and initiated a short, steep descent, which defused the dangerous approach. The PowerFlarm collision warning that sounded immediately afterward occurred about 5 seconds before the point of minimum separation and was therefore of little help. This late warning was due to the system, since the PowerFlarm could only receive the HB-SDM's non-directional transponder signals and the HB-SDM was not equipped with a Flarm-compatible device.
Thanks to the vertical avoidance maneuvers of both aircraft, the vertical separation at the point of closest approach was about 300 ft. Without corrections to the vertical flight paths, the two aircraft would have crossed at approximately the same altitude.

Accident investigation:
Investigating agency: STSB
Report number: 
Status: Investigation completed
Duration: 2 years and 4 months
Download report: Final report


Revision history:

31-Mar-2021 13:55 harro Updated [Registration, Cn, Operator, Departure airport, Destination airport]
25-May-2023 17:31 harro Updated [[Registration, Cn, Operator, Departure airport, Destination airport]]

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