On March 21, 2004, at 1000 Pacific standard time, an amateur built, experimental category, Menefee RAF Vari-Eze airplane, N200TZ, sustained substantial damage during a hard landing at the Bremerton National Airport, Bremerton, Washington. The airplane was being operated as a visual flight rules (VFR) local flight under the provisions of 14 CFR Part 91, when the accident occurred. The private pilot, the sole occupant of the airplane, received minor injuries. Visual meteorological conditions prevailed and no flight plan was filed for the flight. During a telephone conversation with the National Transportation Safety Board IIC, the pilot reported that shortly after takeoff the aircraft developed a rough running engine. The pilot stated he turned back toward the departure runway (19/1), but was unable to land due to traffic on the runway. The pilot stated he entered the traffic pattern and continued to the south for a landing on the departure runway. The pilot said the airplane was low, slow and unresponsive to roll inputs after turning final. Shortly after turning final, the pilot reported that the airplane "pancaked" in, coming to rest in a grassy area adjacent to runway 19. The pilot reported that he believed the rough running engine was caused by a fouled sparkplug. An FAA inspector from Seattle, Washington, Flight Standards District Office inspected the airplane after the accident and reported that there was no evidence found to indicate a mechanical failure and the cause of the engine vibration was undetermined. The airplane was powered by an E81T Subaru engine rated at 100 horsepower.