History of Flight
On April 30, 2014, at about 1055 Pacific daylight time, an experimental amateur-built Pulsar XP, registration N452PC, sustained substantial damage during landing at Bremerton National Airport (PWT), Bremerton, Washington. The pilot-owner was not injured. The flight was conducted under 14 CFR Part 91 with visual meteorological conditions prevailing; no flight plan was filed.
According to the pilot, who also built the kit airplane based at PWT, he took off around 1000 for a local flight. While airborne, he received a radio call from the Avian Flight Center fixed base operator (FBO). FBO personnel reported that a passer-by had seen something fall from an airplane, later identified as a nose landing gear (NLG) wheel and tire assembly, which they believed belonged to N452PC. The pilot returned to PWT and conducted a flyby for FBO personnel to confirm the loss. The FBO coordinated with the pilot to postpone landing until the airport was closed to other traffic and fire/rescue personnel were present. After about 30 minutes, the pilot was cleared to land. He landed with full flaps at minimum speed; the airplane touched down normally, settled onto the NLG strut, and stopped on the runway.
Aircraft Information
The pilot completed construction of the Pulsar XP in 1998 and had accumulated approximately 811 hours on it, out of 884 total flight hours. The airplane was powered by a Rotax 912UL series engine. About two days after the accident, the pilot learned from another Pulsar operator that there had been five previous NLG separations on Pulsar airplanes. Reportedly, a new NLG fitting had been designed by another owner to address a corroded attach bolt that was difficult to access and inspect, and these failures only affected Pulsar "Series 1" models, the same as the accident airplane. The kit manufacturer was no longer in business, so no additional information on the modification was obtained during the investigation.
Wreckage and Impact Information
The airplane came to rest upright about 150 feet beyond the numbers of runway 2, just left of the centerline. The NLG strut and lower cowl were crushed and scraped, both blades of the wood propeller were fractured, and the firewall was fractured in at least two locations.
Examination by FAA personnel revealed that the pivot shaft enabling the NLG wheel and tire assembly to caster for directional control had fractured, allowing the NLG fork to depart the airplane during takeoff. Photographs of the fracture surface, reviewed by an NTSB metallurgist, indicated the fracture patterns were consistent with reversed bending (bi-directional) fatigue. According to the builder/owner/pilot, the shaft was a solid 4130 steel rod that nested and was welded into the tubular steel nose gear leg, and on which the NLG fork assembly was mounted and rotated. The shaft fractured just inside the lower end of the NLG leg tube.