Factual Information
The aircraft, a Cessna 172G registered as YU-DOT, was operated by a private owner and used for flight training by the organization "Pegaz" at Lisiciji Jarak Airport. On 10 April 2008, the aircraft completed several flights earlier in the day. The last flight was a training session with an instructor and a student pilot practicing touch-and-go landings. After the fifth landing, the crew taxied towards the end of runway 15 at a low speed (4-5 km/h). When the student pilot commanded a right turn to exit the runway, the nose wheel detached, causing the nose fork to dig into the ground and the propeller to strike the ground twice. The crew shut down the engine, magnetos, master switch, and fuel valve, and exited the aircraft without injury.
No injuries or fatalities occurred. The aircraft sustained damage to the propeller (blades deformed and bent backward). The engine required partial disassembly for inspection. The following hardware connecting the nose wheel to the fork was not found at the accident site: bolt (part number AN5-47), bushing (0543001), nut (AN310-5), and cotter pin (MS24665-134). No damage was observed on the fork or other components.
Analysis
The investigation determined that the accident occurred at a very low taxi speed, ruling out crew actions as a cause. The nose wheel attachment design uses a bolt, bushing, nut, and cotter pin to secure the wheel to the fork. Examination of the fork showed no evidence of fracture or damage. The missing hardware indicated that the wheel had become detached due to the absence of these securing elements. The aircraft did not have an approved maintenance program, which would have included proper installation and inspection of these components.
Conclusions
The Commission concluded that the nose wheel detached from the fork because the securing hardware (bolt, bushing, nut, cotter pin) was missing. The absence of an approved maintenance program was identified as an indirect factor, as it would have ensured the correct assembly and inspection of the nose wheel attachment.
Cause
The immediate cause of the accident was the detachment of the nose wheel from the fork due to missing hardware (bolt AN5-47, bushing 0543001, nut AN310-5, cotter pin MS24665-134) that connected the wheel to the fork. The indirect cause was the absence of an approved aircraft maintenance program.