N878NTl Ultralight Sro STINGSPORT · 2006

The pilot was returning to his home airport at an altitude of about 2,000 ft msl. He reported that there was a sudden and violent vibration throughout the airplane that lasted several seconds. The airplane’s canopy unlatched and opened due to the vibration and the engine lost power immediately afterward. The pilot established the airplane’s best glide speed and instructed the passenger to set the transponder to 7700 and to hold the canopy closed. The pilot conducted an emergency landing to a field. During the landing on uneven terrain, the right main landing gear collapsed, followed by the nose landing gear, and the right wing contacted the ground before the airplane came to rest. During a postaccident interview, the pilot reported that he realized the propeller had failed in flight. The airplane’s fuselage was substantially damaged during the accident sequence.

Postaccident examination of the airplane revealed that two of the three wood/composite propeller blades were separated from the propeller hub. The blades were not recovered and thus could not be examined. According to the propeller manufacturer, the propeller was required to be overhauled every 300 flight hours, or 5 (calendar) years, whichever came first. Review of the airplane’s maintenance records revealed that the new propeller had been installed onto the airplane nearly 7 years and nearly 510 hours before the accident. There were no entries documenting that the propeller had undergone the prescribed overhaul during that time. Given this information, it is likely that the propeller blades separated in flight, and that the failure of the propeller blades was due to an exceedance of the manufacturer’s overhaul requirement.