ERA15LA381

The commercial pilot of the experimental amateur-built airplane stated that, during landing on the turf runway with an 8-knot crosswind, the nose landing gear collapsed and the airplane nosed over and came to rest inverted. Examination of the nose landing gear fork and doubler revealed that the materials and construction met manufacturer's specifications. Additionally, the assembly exhibited kinematic deformation, indicative of side loading. Therefore, it is likely that the pilot failed to adequately compensate for the crosswind conditions during landing, which resulted in the side loading of the nose landing gear and its subsequent collapse.

On August 7, 2015, about 1400 eastern daylight time, an experimental amateur-built Zenith STOL CH 750, N330B, was substantially damaged by a nose landing gear collapse and nose-over event after landing at a private grass airstrip in Charlotte, Vermont. The commercial pilot and a passenger were not injured. Visual meteorological conditions prevailed, and no flight plan was filed for the personal flight, which was conducted under the provisions of Title 14 Code of Federal Regulations Part 91.According to the builder/owner of the airplane, the pilot and the passenger were flying the airplane because the passenger was interested in purchasing it. According to the pilot, he established the airplane on a "normal" approach for landing at the airplane owner's private airstrip, after picking up the passenger and completing a short flight in the local area. The pilot reported the runway was oriented 190 degrees, and that there was a crosswind from 270 degrees at 8 knots. Upon touchdown, the nose landing gear fork "deformed," the wheel locked, and dug into the turf. The airplane then nosed over. The wings, firewall, and vertical stabilizer were substantially damaged. A witness familiar with the airplane said she saw the landing, but not the nose-over event. She said the landing appeared "a little faster than I had seen before." The pilot held a commercial pilot certificate with ratings for airplane single engine land, multiengine land and instrument airplane. His most recent second-class medical certificate was issued on June 16, 2015. The pilot reported 2,130 total hours of flight experience, of which 46 hours were in the accident airplane make and model. The two-seat, single-engine, high-wing airplane was manufactured in 1974 and was equipped with a Continental O-200 series engine. Its most recent annual inspection was completed on September 18, 2014. At the time of the accident, the airplane had accrued 54.8 total aircraft hours. The pilot suggested that because the replacement nose landing gear assembly received after the accident was "more robust" than the originally-installed assembly, the original design was "too lightweight." The nose landing gear fork and doubler assembly was examined in the NTSB Materials Laboratory in Washington, DC. Examination revealed that the materiel and the dimensions of the assembly met the specifications of the manufacturer's engineering drawings. Additionally, the "kinematic deformation" of the doubler assembly was consistent with a side-load application.