Incident Overview
On 26 May 2020, at approximately 10:07 local time, an incident occurred at Rybnik Airfield (EPRG) involving a Sirius TL-3000 ultralight aircraft operated by a private owner. The pilot was conducting a technical flight after the aircraft had been parked for about 45 days. The flight included circuits and a local area flight to check aircraft systems. The incident happened after landing, during taxi-off from runway 30.
Aircraft and Pilot Information
The aircraft was a Sirius TL-3000 ultralight, with no registration marks applicable. The pilot, a 52-year-old male, held a valid Czech Republic pilot license with instructor privileges and reported approximately 2,600 total flight hours. No injuries were sustained.
Sequence of Events
After performing checks at 3,500 ft, including flap operation and propeller RPM control, the pilot landed on runway 30 (300°). During the landing roll, when he attempted to exit the runway, the aircraft did not respond to rudder input. The pilot used differential wheel brakes to steer toward the hangar. Upon exiting the cockpit, he noticed the nose of the aircraft was lower than usual and the propeller blade tips were damaged. He immediately reported the incident to the State Commission on Aircraft Accident Investigation (PKBWL).
Damage and Investigation
Inspection revealed a fatigue fracture of the nose gear strut at the upper attachment weld joint. The weld showed signs of poor quality: irregular shape, pitting, and grinding. During welding, localized overheating had occurred, weakening the material. The fracture caused the nose to drop, allowing the propeller blades to contact the runway surface, damaging the propeller and laminates around the nose gear mounting area. The manufacturer later replaced the nose gear strut with a redesigned part that eliminated the welded joint.
Cause and Contributing Factors
The direct cause was a fatigue fracture of the nose gear strut at the boundary of the welded joint near the upper attachment. A contributing factor was the reduced material strength in the weld area due to localized overheating during the welding process.