What happened
On August 15, 2013, a TL-3000 Sirius ultralight aircraft landed on the grass runway at EPRZ after completing ten training circuits. During the final phase of the landing roll, while the aircraft was at a minimal ground speed, the nose gear strut underwent a torsional and bending failure below the lower attachment point to the fuselage. This structural failure caused the propeller blade to strike the ground, resulting in the destruction of one propeller blade and damage to the engine cowling. No injuries were reported following the incident.
The investigation
The investigation examined the mechanical failure of the nose gear assembly and the operational history of the aircraft. Investigators reviewed the damage to the nose gear strut, the propeller, and the engine cowling. The investigation also considered the aircraft's previous usage history, noting that between June 2011 and June 2012, the aircraft had been operated by a flight school in the Czech Republic.
Findings
- The primary cause of the incident was the failure of the nose gear strut due to exceeding the material's strength limits.
- The aircraft's prior two-year period of use in a flight school likely contributed to accelerated structural fatigue, as student pilots may have subjected the airframe to increased loads during imperfect landings.
- The failure was triggered when the aircraft encountered a transverse irregularity on the grass runway surface during the landing roll.