What happened
On June 13, 2010, a HOAC Austria HK 36 R Super Dimona motor glider was conducting a private VFR flight from Uetersen to Riedlingen. During the flight, the pilot performed a refueling stop at Schwäbisch Hall, departing at 13:39 local time.
Shortly before 14:00, witnesses in Neidlingen observed the aircraft flying south into the valley, where it disappeared into low-hanging clouds near the Albkante ridge. Other observers near Schopfloch noted the aircraft flying from the north, disappearing into cloud cover, and reappearing on a northward heading approximately one minute later, before once again entering the clouds near the ridge.
At approximately 14:00, members of a mountain rescue team conducting an exercise near the Reußenstein castle ruins heard a loud bang and saw a shadow passing over the treetops. The motor glider had collided with trees on a steep slope. The impact caused the destruction of the aircraft and resulted in two fatalities.
The investigation
The BFU investigation examined the flight path using GPS data from a Garmin 150XL and a Garmin 90 unit. The investigation also analyzed meteorological data from the German Weather Service (DWD) and radiosonde ascents from Stuttgart.
Investigators determined that the aircraft struck the trees while flying on a northeasterly course with a 15-degree right bank. The collision tore away parts of the wings and tail, and the fuselage was destroyed upon impact with the ground. No fire occurred at the site.
Findings
- The aircraft was flying in conditions with extremely low visibility; witnesses reported visibility in the valley was approximately 20 meters.
- While official weather reports indicated VFR conditions for the broader region, local conditions at the Albkante ridge were characterized by low cloud layers and fog caused by a weak northern/northeastern airflow.
- The pilot had not obtained updated weather information from an aviation advisory center prior to the flight.
- The aircraft was a composite low-wing design with a T-tail, operated by a club and registered in Germany.