Summary of Event
On April 7, 2019, at approximately 12:14 local time, a KR-30 Topaz ultralight aircraft was landing on asphalt runway 11R at Krośno airport (EPKR). After a normal touchdown, the nose landing gear leg developed self-excited oscillations, known as shimmy. The pilot lost directional control during the landing roll. The aircraft began to veer to the right and, at a speed of about 20 km/h, departed the runway onto the grass area. During the excursion, the nose wheel and then the nose landing gear leg were broken off. The engine was still running, and the propeller blades struck the ground, resulting in blade fractures.
Damage
As a result of the event, the aircraft sustained minor damage. The pilot suffered no physical injuries.
Cause
The investigation determined that the cause of the incident was the occurrence of self-excited vibrations (shimmy) of the nose landing gear leg of the aircraft.