CEN10LA551

The airplane encountered a rise in the turf runway during the landing rollout. The nose landing gear left the ground momentarily and when it came back down it partially collapsed causing the airplane to nose over. The pilot noted that he had relaxed the flight controls and did not have the elevator held up at the time. He added that this was his third landing on the runway that day, and that he normally tried to avoid that area of the runway. A postaccident inspection revealed that the nose landing gear remained attached to the engine mount. However, the strut was curled aft with the nose wheel assembly rotated approximately 90 degrees. The nose wheel assembly and fairing remained attached to the strut. The airplane sustained substantial damage to the fuselage, left wing, and empennage when it nosed over. Examination of the runway noted a slight rise approximately one-third of the way down the runway. A ground scar consistent with being formed by the nose landing gear was observed down field from the rise. The nose landing gear had been modified in accordance with the airplane kit manufacturer's service bulletin. The bulletin provided for additional ground-to-nose landing gear fork clearance in an effort to reduce the possibility of nose gear collapse and nose over accidents. A review of prior accident reports involving collapse of the nose gear during landing rollout indicated that they all occurred on unpaved runways.

On September 18, 2010, about 1930 eastern daylight time, an experimental, amateur-built McCauley RV-6A airplane, N343BG, nosed over when the nose landing gear collapsed during landing rollout at Glenndale Airport (8I3), Kokomo, Indiana. The pilot and passenger sustained minor injuries. The airplane sustained substantial damage to the fuselage, left wing, and vertical stabilizer. The aircraft was registered to and operated by the pilot under the provisions of 14 Code of Federal Regulations Part 91 as a personal flight. Visual meteorological conditions prevailed for the flight, which operated without a flight plan. The local flight originated from 8I3 at 1915. The pilot reported that he landed and the airplane rolled out for approximately 300 to 400 feet when it encountered a rise in the turf runway. He estimated that the airplane was traveling about 45 miles per hour at the time. The nose landing gear left the ground momentarily and when it came back down it partially collapsed causing the airplane to nose over. The pilot noted that he had relaxed the flight controls and did not have the elevator held up at the time. He added that this was his third landing on the runway that day, and that he normally tried to avoid that area of the runway. The nose landing gear remained attached to the engine mount. However, the strut was curled aft with the nose wheel assembly rotated approximately 90 degrees. The nose wheel assembly and fairing remained attached to the strut. In addition, the fuselage, left wing, and empennage were damaged when the airplane nosed over. Examination of the runway noted a slight rise approximately one-third of the length down the runway. A gouge or ground scar about 40 feet long was observed down field from the rise. Its size and location was consistent with being formed by the nose landing gear. The accident airplane was issued an experimental, amateur-built airworthiness certificate on June 7, 2003. According to maintenance documentation provided to the NTSB, the most recent condition inspection was completed on September 10, 2010. There were no maintenance log entries subsequent to that inspection. The log indicated that the nose landing gear was modified in September 2008 in accordance with Van's Aircraft Mandatory Service Bulletin 07-11-09, related to increased axle-to-ground clearance. The service bulletin, dated November 9, 2007, was applicable to all two-place, tricycle landing gear equipped RV models with finish kits shipped prior to February 2005. Compliance was recommended at the next conditional inspection. Depending on the exact nose landing gear strut installed, the bulletin suggested replacement or modification of the strut. Compliance with the bulletin provided approximately one-inch of additional clearance between the nose wheel fork and the ground. Although the manufacturer did not draw any correlation between previous accidents and the fork-ground clearance, the bulletin did note that additional clearance mayreduce the likelihood of such accidents. In response to an August 2005 accident (NTSB case no. ANC05LA123), the NTSB conducted a study of the nose landing gear configuration. The study concluded that the nose landing gear strut had sufficient strength to perform the intended function. The study also noted that several factors can influence the nose landing gear strut ground clearance, including the weight of the installed engine, tire pressure, and runway condition. According to NTSB records, previous accidents involving collapse of the nose gear during landing rollout involved unpaved runway surfaces, with the exception of events with documented contributing factors such as hard landings, bounced landings, or off-airport landings. None of the reports associated with these previous accidents noted compliance with the service bulletin.