Synopsis
On 3 May 2006 at 18:24 local time, a Robin DR400-180R aircraft, registration HB-KOC, operated by Segelfluggruppe Bern, departed from Bern-Belp Airport on a glider towing flight. During takeoff, an engine malfunction occurred. The pilot subsequently did not take several available opportunities for an emergency landing. The aircraft made uncontrolled ground contact at Hühnerhubel, in the municipality of Belp, approximately 600 meters southwest of the airport, resulting in a rollover and subsequent fire. The cockpit canopy's Plexiglass could not be broken from inside due to the absence of a suitable tool, which transformed an otherwise survivable accident into a fatal one.
Investigation
The investigation was conducted by the Swiss Aircraft Accident Investigation Bureau (AAIB). The aircraft was a Robin DR400-180R, a single-engine four-seat monoplane with a fixed-pitch propeller. The pilot held a valid license and had adequate flying experience for glider towing operations. The aircraft had been maintained in accordance with regulations. Weather conditions at the time were not a contributing factor. The engine and airframe were examined; no pre-existing technical defects were found that could have caused the engine malfunction.
Cause
The accident was caused by the pilot failing to take several available opportunities for an emergency landing after an engine malfunction, leading to uncontrolled ground contact, rollover, and fire. The lack of a cockpit tool to break the Plexiglass canopy resulted in the otherwise survivable accident having a fatal outcome.
Safety Recommendations
As a result of the investigation, Safety Recommendation No. 403 was issued to address the deficiency in cockpit emergency equipment. Additionally, the Segelfluggruppe Bern implemented measures regarding the use of radio frequencies during glider operations at Bern-Belp.