Incident Summary
On 14 April 2018 at 16:00 local time, a DG-400 glider (registration HB-2070) was on approach to grass runway 28 at St. Gallen-Altenrhein (LSZR). The pilot, a 58-year-old Swiss national holding a Light Aircraft Pilot Licence for gliders, had logged 651 flight hours total, with 115 hours on type. During the approach, the pilot realized that while he could receive radio transmissions, he was unable to transmit. Meanwhile, a tow plane and another glider were preparing for departure on the same runway. To avoid conflict, the pilot decided to touch down before the runway start in a field with high grass. After touchdown, the glider rolled approximately ten meters before rotating 180 degrees around the vertical axis (a ground loop). The fuselage was torn and the tail wheel bent. The pilot remained uninjured.
Investigation Details
The Swiss Transportation Safety Investigation Board (STSB) conducted a summary investigation. According to the pilot, the radio functioned normally before the flight. During approach, he could hear other transmissions but could not send. In such a situation, making blind calls would have been appropriate. Inspection of the radio system after the incident revealed that the installation was generally in order, but the push-to-talk button had a broken solder joint. The investigation noted that numerous control movements during flight may have caused the electrical connection to fail, as it had been checked and found working during the pre-flight inspection. There was no redundant solution for the push-to-talk in the cockpit, so the pilot could only receive, not transmit.
Findings
The radio failure prevented the pilot from communicating his intentions. The pilot's decision to land before the runway to avoid the tow plane was considered forward-looking. The aircraft sustained light damage: a torn fuselage and bent tail wheel. No third-party damage occurred.
Conclusions
The STSB concluded that no further investigation was necessary, as no additional safety-relevant findings were expected. The investigation was closed with this summary report.