Accident Overview
On May 24, 2015, about 1445 Pacific daylight time, a Czech Aircraft Works Spol Sro SportCruiser airplane, registration N642JB, experienced a nose gear collapse during landing at Fresno Chandler Executive Airport, Fresno, California. The solo pilot was not injured. The airplane was operated as a 14 Code of Federal Regulations Part 91 personal flight. Day visual meteorological conditions prevailed, and no flight plan was filed. The flight departed from and remained in the traffic pattern at Fresno Chandler Executive Airport.
Pilot Account
According to the pilot, on the third landing, as the nose gear touched down, an immediate shimmy developed that sounded "clunky." During the landing roll, the nose gear collapsed and the airplane skidded to a stop on the runway. The pilot stated that the landing flare was "normal" and the main landing gear touched down first. No anomalies had been noted with the nose gear during the first two landings. The airplane sustained substantial damage to the firewall.
Nose Gear Examination
The nose gear assembly was sent to the National Transportation Safety Board (NTSB) Materials Laboratory in Washington, DC, for examination. The nose gear leg assembly consisted of one-inch-diameter bent tubing with welded brackets at each end. The examination revealed that the leg was fractured through the tube at the weld joint in the upper attachment area. Optical examinations showed separation topographies, beach marks, and recontact damage consistent with progressive fatigue cracking. Closer magnification uncovered multiple fatigue fracture origins at the forward toe of the assembly weld on the left side of the tube. The fatigue penetrated about 50 percent of the tube cross section and was consistent with side-to-side loading. The remaining fracture was consistent with overstress.
Aircraft Information
The airplane had accumulated 870.1 total hours since new. The most recent annual inspection was completed on May 11, 2015, and the airplane had accrued 2.0 hours since that inspection. The airplane owner, a Light Sport Aircraft Repairman, performed the annual inspection and reported that nothing abnormal was noted with the nose gear leg assembly. The owner identified the nose gear leg as a "second generation" nose gear (SG0270N), but consultation with the manufacturer identified it as a first generation nose gear leg (SG0040N).
Service Bulletin
The first generation nose gear assembly was manufactured by Czech Aircraft Works (CZAW), a company that became insolvent in 2009. Czech Sport Aircraft, which provided continued airworthiness support for SportCruiser airplanes, had issued several upgrades and design changes. On July 10, 2014, Czech Sport Aircraft issued a service bulletin (SB-CR-016) containing instructions to replace the nose landing gear with an "Improved Nose Landing Gear Assembly (SG0300N)." The bulletin stated that some aircraft had developed cracks in the lower section of the nose landing gear SG0270N and that the improved gear had better fatigue-resistant properties. Compliance with this service bulletin was not required by the Federal Aviation Administration and was an "aircraft owner decision."