SONOMA, CA, USA
N55961
Raymond C. Voegele MINI IMP RC-2
After takeoff, the pilot noted a partial loss of engine power and attempted to land in an open field; however, the airplane's landing gear struck trees and it collided with the roof of an occupied house. The pilot stated that the engine did not sputter, surge, or backfire, and the engine was just not producing full power. Examination of the airplane disclosed that there was a loose magneto cap with one screw missing, and the other two were only engaged by three threads. Interference was also found at the midpoint of the throttle control system as a result of the improper routing of that system in the airframe, and a misrigged carburetor heat box, which resulted in an inability to achieve full throttle movement at the carburetor.
HISTORY OF FLIGHT On August 15, 1998, at 1235 hours Pacific daylight time, an experimental Voegele Mini Imp RC-2, N55961, experienced a partial loss of engine power after takeoff from runway 8, and subsequently impacted a residence at Sonoma Skypark, Sonoma, California. The airplane, operated under 14 CFR Part 91, sustained substantial damage. The private pilot/owner was not injured. The individual inside the residence was not injured. Visual meteorological conditions existed for the local area personal flight and no flight plan was filed. In a written report, the pilot stated that this was his second flight of the day and he was going to stay in the pattern. He stated that he had refueled that day with approximately 5 gallons of fuel. He reported that other pilots who had refueled their airplanes on the day of the accident noted no discrepancies. According to the pilot, the total fuel capacity was 12 gallons, with 9 gallons usable. He stated that the airplane burns approximately 4 gallons per hour. During the engine run-up, the pilot reported that no discrepancies were noted and he "checked for fuel levels," and found them all to be adequate for the short flight. He rotated at 65 mph, and "at the end of the field, while already airborne at approximately 150 feet, the engine started to lose power." The pilot stated that he had to maneuver to avoid power lines at the end of the field, and to avoid two large trees. The airplane hit a smaller tree between the two larger trees, then descended into a house. The pilot reported that the engine was still running after impact and that he shut it down before evacuating. The pilot reported to a Safety Board investigator that "there was no surging, vibrations, sputtering, or backfiring. It was smooth running, just loosing power." He noted that the engine sound was constant throughout the accident sequence. A local resident, an airframe and powerplant (A & P) mechanic witnessed the accident and reported that the airplane made a normal takeoff. He stated that the airplane "departed from runway 8 and maneuvered to essentially a right turn 80 degrees off runway centerline." He noted that the airplane gained about 100 to 150 feet of altitude and he heard power fluctuations coming from the engine. He stated that the airplane appeared to be in a level attitude when it crashed into the house roof. The airplane came to a rest on top of an occupied house 1/4 mile from the airport. The roof of the house had a 4-foot-diameter hole in it from the airplane. AIRCRAFT INFORMATION The airplane's original owner/builder was interviewed by a Federal Aviation Administration (FAA) inspector concerning the airplanes history. The original owner stated that when the airplane was originally certified by the FAA, it had a turbocharged Revmaster engine installed. He reported that the turbocharged engine remained on the airplane throughout his ownership. He stated that in 1985, he had a "serious accident" and donated the airplane to Wings of Hope, a charity organization. The donation to the charity was based on the understanding that the airplane would not fly again, and would be used as a training aid at the mechanic's school. The original owner further stated that the airplane was delivered in six major pieces on a trailer and was not certified or airworthy. During the interview, the first owner reported that the "Mini-Imp pusher type airplane was hard to takeoff and that pusher airplane behaved much differently with the controls." He stated that he believed that "a pilot with a commercial rating would likely not have the reserve power that they are accustomed to." He further reported that he believed that the accident airplane tended to be underpowered. The airplane remained in the possession of the charity until 1990, when the airplane was sold to the third owner, without the engine. In a written statement to the FAA Flight Standards District Office (FSDO) in Oakland, California, the third owner stated that after doing research, he decided to install a zero-time Great Plains 2180cc nonturbocharged engine. He reported that he used the same engine mount and drive train in the installation. The third owner reported that he made a logbook entry concerning the purchase of the airplane and that it did not come with an engine. He also stated that he made a second entry that reflected the new engine installation, along with the fact that the "engine still required max power testing." The third owner contacted a designated engineer representative (DER) regarding the engine change. The DER recommended a reinspection of the installation, and the reissuance of a new set of operating limitations, as well as the issuance of a new airworthiness certificate. The third owner did not follow through with this, and sold the airplane to the current owner. At the time of sale, the third owner informed the fourth owner that a DER recommended that an inspection, and that a new airworthiness certificate would have to be issued. During the sale of the airplane on December 20, 1997, the third owner informed the current owner that the airplane was not in an airworthy state. The bill of sale that was signed by both individuals stated, "this is a Bill of Sale for airplane N-55961 . . . The airplane is currently in an unairworthy status and buyer agrees to purchase the airplane as-is." The third owner believed the airplane to be in an unairworthy condition because the DER had not inspected it and reissued a new set of operating limitations or a new airworthiness certificate. He stated that the logbook that was furnished to him when he bought the airplane indicated that the last condition inspection was performed in 1984. The logbook also contained an entry by the original owner stating that the airplane was out of annual. The third owner said that he had only performed a preliminary weight and balance since the addition of the new engine and an official one still needed to be done. The final reason the third owner provided as to why he believed that the airplane was in an unairworthy state was that the airplane was disassembled when he received it, with the propeller, both wings, and the ruddervators unattached. The third owner further noted that the final flight control system installation and rigging check still needed to be performed. The mechanic who performed the inspection of the accident airplane the day after the sale to the current owner was interviewed. He noted that the wings and propeller were found already installed on the airplane prior to his inspection. The owner and mechanic stated that they did not know who had reassembled the airplane. ENGINE INFORMATION The original engine that was installed in the airplane by the original owner was a turbocharged Revmaster 2100DT. According to manufacturer's data, it had a maximum output of 80 horsepower (hp) at 3,200 rpm, with a continuous output of 70 hp at 3,200 rpm at sea level. The engine weighed 196 pounds. The third owner placed a new zero-time Great Plains 2180cc nonturbocharged engine into the airplane. According to manufacturer's data, it had a maximum output of 76 hp at 3,600 rpm, with a continuous output of 70 hp at 3,400 rpm at sea level. The engine weighed 164.5 pounds. The current owner stated that with the Great Plains 2180cc nonturbocharged engine the maximum rpm indication from the propeller and engine was 2,900 rpm. According to a representative from Bradley Aerospace, the Revmaster and Great Plains engines are VW engine conversions for aviation use. All of the various models are considered to be the same, the only difference is who sells them. The engines and parts are 100 percent interchangeable with each other, with no adverse affects noted. The representative further stated that the same engine mounts and drive train could be utilized if the owner replaced a turbocharged engine with a nonturbocharged engine. TESTS AND RESEARCH The airplane was inspected by the FAA on August 20, 1998, at the owner's hangar. The FAA inspector noted a loose magneto cap with one screw missing and two screws only engaged by three threads. She further noted that there was "moderate interference of the throttle control system from improper installation" and the misadjusted carburetor heat box. During an interview with the FAA inspector, the pilot stated that he had reassembled the wings and the engine. The FAA further noted that the current owner was not a mechanic and did not hold a repairman's certificate for the amateur built airplane. According to the current owner/pilot, the logbooks were onboard the airplane at the time of the accident and he believes that the fire department had thrown them away when they were getting the airplane off of the roof because he could not locate them. The FAA was provided with an operating limitations document that was for the original owner/builder of the airplane. The pilot was unable to provide a new operating limitations document or a new airworthiness certificate. According to the FAA, if the airplane is disassembled for any reason by the original builder, there are only two people authorized to reassemble it. The first is the original builder and the second is a certified A & P mechanic, accompanied by an entry in the aircraft logbook with their respective signatures. The FAA further stated that once the airplane is reassembled it must go through the recertification process and a new set of operating limitations and airworthiness certificate has to be issued. The mechanic, who conducted the condition inspection on December 21, 1997, did not have in his possession a copy of the work he had completed. He stated that he made an entry in the aircraft logbook, concerning work completed, but did not make a copy for himself.
A loss of power due to a loose magneto cap and a binding throttle control cable. The deficiencies were the result of the owner/pilot's improper installation and/or adjustments.
Source: NTSB Aviation Accident Database
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