What happened
On June 15, 2013, a Ventus C glider, registration OK-2530, was performing a landing approach at the SLZ Trutnov airfield during an ultralight aircraft rally. While executing the final stages of the approach, the pilot failed to sufficiently correct the aircraft's heading following a turn and the influence of a crosswind.
As the glider leveled out, it was positioned downwind and drifting across the runway toward the parking area. The pilot had deployed landing flaps to assist with the short landing, which increased the aircraft's drag and reduced the effectiveness of the ailerons. During a climbing turn, the glider's left wing struck the trailing edge of the left wing of a stationary Skylane UL, registration OK-MUO 69.
The impact caused the glider to become uncontrollable, leading to a secondary impact with the ground where the cockpit canopy shattered and the rear fuselage broke. The glider subsequently rotated and slid along the runway. While the pilot of the glider escaped without injury, a passenger standing near the door of the stationary ultralight aircraft sustained serious injuries and was transported to a hospital.
The investigation
The ÚZPLN investigation utilized video footage to reconstruct the flight path and analyzed the aircraft's mechanical condition. The investigation established that the Ventus C was airworthy and that the pilot held valid flight qualifications. The investigators examined the aerodynamic effects of flap deployment on the glider's lateral control and assessed the meteorological conditions, which included a southwest wind of 6 to 10 knots.
Findings
- The pilot failed to adequately account for the influence of the crosswind during the approach.
- The deployment of landing flaps, while intended to assist with the short landing, reduced the effectiveness of the ailerons, making the necessary heading correction difficult.
- The pilot did not use the aircraft's brakes, and the glider's momentum caused it to float and climb into the path of the parked aircraft.
- The collision occurred because the glider drifted across the runway width toward the parking area where the Skylane UL was positioned.