What happened
On December 11, 2008, at 19:34 UTC, a Cessna 510, registration OE-FMZ, was taxiing at Prague Ruzyně Airport (LKPR). The aircraft, operated by Wings For Us LTD., was instructed to taxi from parking stand S2 via taxiway R toward holding point RWY 31. The crew consisted of the pilot and two passengers.
During the taxi, the pilot initially followed the yellow taxiway markings but lost visual reference to the lines after a right turn. Relying on onboard GPS for navigation, the pilot turned left approximately 40 meters earlier than intended, causing the aircraft to veer onto an unpaved, grassy area adjacent to the apron. As the aircraft attempted to return to the paved surface, the left main landing gear encountered a 0.17-meter concrete edge. The impact caused the left main landing gear to break off at the trailing link pin. The pilot notified ground control that the aircraft had hit something and requested assistance. There were no injuries to the pilot or passengers.
The investigation
The ÚZPLN investigation examined the aircraft's mechanical condition, the environmental factors, and the pilot's navigational methods. Investigators reviewed the fracture surface of the landing gear axle with the manufacturer, who confirmed that no fatigue-related material changes were present; the failure was consistent with bending and shear forces applied to the critical cross-section. The investigation also analyzed the meteorological conditions, noting that recent rainfall had left the asphalt surfaces wet and reflective, and the visibility was between 800 and 1000 meters under night conditions.
Findings
- The primary cause of the accident was the pilot's loss of orientation, which was exacerbated by distracting light reflections from the wet asphalt surface.
- After losing visual contact with the taxiway markings, the pilot relied on GPS data; a potential error in the GPS display likely led to the premature turn.
- The aircraft's low cockpit height (1.9 meters above the ground) contributed to the difficulty in maintaining visual references amidst the reflections.
- The structural failure of the landing gear was caused by the physical impact of crossing the threshold between the unpaved and paved surfaces, not by material fatigue.
Safety action
To prevent similar occurrences, the following recommendations were made to the airport operator:
- Implement more prominent markings for the exit from the apron to taxiway R to ensure clarity during poor lighting conditions.
- Install supplementary markings to prevent aircraft from exiting onto unmapped or unpaved areas.