What happened
On April 18, 2011, a Diamond HK-36R (Super Dimona) motor glider was performing a local flight from the Niederöblarn airfield in Styria, Austria. The pilot initiated the flight at approximately 14:45 UTC using an auxiliary engine start. During the final approach to runway 04, the aircraft was flying at approximately 110 km/h with the engine at idle.
As the pilot attempted to flare for touchdown, the aircraft bounced, lifting off the runway again after initial contact. In an attempt to correct the flight path, the pilot applied additional back pressure, which triggered longitudinal oscillations around the lateral axis. The pilot was unable to dampen these pilot-induced oscillations. Consequently, the aircraft struck the runway with significant force, causing the nose gear leg to break. The impact forced the propeller into contact with the ground, resulting in damage to the propeller blades, the gearbox, and the propeller governor due to shock loading.
The investigation
The investigation examined the aircraft's mechanical condition, the pilot's recent training history, and the flight parameters. Investigators found no evidence of technical failure or the aircraft exceeding its operational limits. The aircraft's weight and center of gravity were within permissible ranges throughout the flight.
Records indicated that the pilot had been undergoing training in various high-wing and low-wing motor gliders, including the SF 25 C Falke, in the weeks preceding the accident. Notably, the pilot had recently completed 38 flights in a KA7 glider, a high-wing aircraft, which exhibits different ground effect characteristics than the low-wing Diamond HK-34R.