What happened
On July 22, 2020, a DG-400 glider, registration SE-UYX, was conducting a cross-country flight originating from Johannisberg airport. After approximately two hours of flight, the pilot decided to terminate the navigation due to deteriorating weather conditions. As the aircraft descended, the pilot realized that the original destination could not be reached and began searching for a suitable site for an out-landing.
The pilot identified a field near Surahammar that appeared to have low-lying vegetation. During the approach, the pilot attempted to restart the onboard engine to maintain altitude and avoid the out-landing; however, the engine failed to start. The pilot subsequently decided to proceed with the landing in the selected field. Upon touchdown, the aircraft's tailwheel contacted the crops first. As the glider moved through the field, the left wing encountered significant resistance from the crops, causing it to break away from the fuselage. The aircraft also sustained damage to the cockpit and the main wheel.
The investigation
The Swedish Accident Investigation Authority (SHK) examined the aircraft, the landing site, and interviewed the pilot and a club member. The investigation reviewed GPS data, which confirmed that the pilot maintained a sufficient altitude margin during the final approach and that the landing speed and sink rate were appropriate for the circumstances. The investigation also reviewed the engine start procedures and the manufacturer's manual.
Findings
- The out-landing was performed in a field that was actually growing nearly ripe oats, which provided more resistance than the pilot had anticipated.
- The engine failure to start was a primary factor in the necessity of the out-landing, though the investigation noted that such failures are common for this engine type and pilots should not rely on them for safety.
- The pilot did not utilize the choke during the engine start attempt, despite the manual's instructions for cold starts, though the pilot noted this was common practice at the club.
- The structural failure of the left wing was caused by the sudden and uneven deceleration as the wing became entangled in the tall crops.
- The pilot's planning and execution of the out-landing approach were considered correct and appropriate for the conditions.