SEA08LA190

As the airplane departed on its maiden flight, witnesses reported hearing the engine "cut out" then start again before completely losing power. The airplane was subsequently observed in "a tight spiral" with its wings "pointing straight up and down" before impacting terrain and sliding into the side of a school building. The airplane came to rest in an inverted position. Fuel was detected at the accident site and there was no post crash fire. A Federal Aviation Administration airworthiness inspector reported that the carburetor's mixture control lever had separated from its mixture shaft, and that the carburetor's metering valve shaft appeared to have been slightly bent and grooved for some time.

HISTORY OF FLIGHT On August 29, 2008, about 1230 Pacific daylight time, a Zodiac 601 XL experimental amateur built airplane, N9881T, was substantially damaged following in-flight collision with terrain and a building while maneuvering near Coeur d'Alene, Idaho. The pilot, the sole occupant, was killed. The flight was operating under the provisions of 14 Code of Federal Regulations (CFR) Part 91, and a flight plan was not filed. Visual meteorological conditions prevailed at the time of the accident. The local flight departed the Coeur d'Alene Air Terminal (COE), Coeur d'Alene, Idaho, about 1225. In statements provided to the National Transportation Safety Board investigator-in-charge (IIC) by local law enforcement personnel, several witnesses reported hearing the airplane's engine "cut out," then start up again before it "stopped completely." The witnesses further reported observing the airplane in a turn to the left before "it spiraled down in a tight spiral totally on its side, wings pointing straight up and down." Witnesses stated that one of the airplane's wing tips impacted the ground, flipped over and slid into the side of a school building. Witnesses also reported observing fuel leaking after the airplane had come to rest. A Federal Aviation Administration (FAA) airworthiness inspector reported that an onsite examination of the airplane revealed that the carburetor's mixture control lever was observed separated from its mixture shaft. The inspector further reported that all necessary components for flight were accounted for, and that fuel was present at the accident site. There was no postcrash fire. The airplane was subsequently removed from the accident site for further examination. PERSONNEL INFORMATION According to Federal Aviation Administration (FAA) records, the pilot, age 65, held a private pilot certificate with an airplane single-engine land rating. The pilot's most recent aviation medical examination was completed on June 26, 2003, when he was issued a third-class medical certificate with the limitation, "Must wear corrective lenses for near and distant vision." According to information provided by the pilot on his airman's medical application, the pilot listed a total time of 900 hours, with 20 hours in the past 6 months. The pilot's personal logbook was not recovered during the course of the investigation. AIRCRAFT INFORMATION The accident airplane was an amateur built Zodiac 601 XL, serial number 6-5407. This was the maiden flight of the all-metal airplane, which incorporated a low-wing design with a fixed tricycle landing gear. The airplane had a maximum gross weight of 1,320 pounds and could accommodate two occupants. The airplane was equipped with a 100 horsepower GM Corvair 6 cylinder engine, which was converted for airplane use. A review of the owner's aircraft maintenance records revealed that the airplane's engine was first run on February 14, 2008, with a note, "First run of engine. Carb problems." A second entry,which was made on June 10, 2008, read "Replaced discharge nozzle. Runs much better. Adjusted mixture and idle." A third entry, dated August 1, 2008, was annotated "Run-up and taxi-tests." Maintenance records further revealed that on August 15, 2008, the pilot entered the following in the aircraft logbook: "I certify this aircraft has been inspected in accordance with the scope and detail of Appendix D to Part 43 and has been found to be in a condition for safe operation." The entry was followed by the pilot's signature. On August 16, 2008, a representative from the FAA issued the pilot/owner a Special Airworthiness Certificate and Operating Limitations for the airplane. The aircraft log indicated a total time of 0 hours, and a tachometer time of 5.2 hours. METEOROLOGICAL INFORMATION At 1235, the COE Automated Weather Observing System (AWOS), located about 1 nautical mile north of the accident site, report wind 150 degrees at 4 knots, visibility 10 miles, few clouds at 5,000 feet, temperature 24 degrees Celsius, dew point 13 degrees Celsius, and an altimeter setting of 29.93 inches of Mercury. WRECKAGE AND IMPACT INFORMATION FAA inspectors reported to the IIC that the airplane had come to rest in an inverted position resting up against the corner of an elementary school building, which was located about 1 mile south of the departure airport. The inspector confirmed that fuel was present at the accident site. The inspector further stated that an onsite examination of the wreckage indicated impact damage to the engine, and that both composite propellers and the airframe were destroyed. MEDICAL AND PATHOLOGICAL INFORMATION On September 1, 2008, an autopsy was performed on the pilot at the Spokane Medical Examiner's Office, Spokane, Washington. The cause of death was listed as blunt force trauma to the head. The FAA's Civil Aeromedical Institute (CAMI) in Oklahoma City, Oklahoma, performed toxicology tests on the pilot. The results were negative for drugs and alcohol. TESTS AND RESEARCH A FAA airworthiness inspector, who conducted a post-accident examination of the engine, reported that the engine's carburetor had shown signs of age and that the metering valve shaft "appeared to have been slightly bent and grooved for some time." The inspector stated, "The mixture control lever's lean/rich stop had been previously broken off and filed smooth." He further reported "...the mixture control arm appeared to have easily separated from the metering valve shaft during the aircraft's maiden flight. The mixture control cable was secured to the firewall, not to a bracket on the engine."