SEA08LA127

The pilot had recently installed an overhauled carburetor and new air inlet on the airplane. Because the airplane had not been flown for about nine months, the pilot drained all of the old fuel out of the airplane and refueled it. Witnesses reported that the pilot performed an extensive engine run up that lasted 10 to 15 minutes, and with satisfactory results, the pilot decided to take the airplane around the airport traffic pattern. A witness based at the airport said that during the initial takeoff, the engine sound was smooth. As it continued, the witness heard the engine running rough. When the airplane flew past the witness about 300 feet above the runway, the witness saw two puffs of white smoke. The airplane appeared to have adequate airspeed and it was still climbing, although the engine was cutting out. The engine then cut out completely and the airplane continued straight ahead for about 1 second. The airplane entered a slow turn to the right, and when it had turned approximately 160 degrees, the right wing stalled and the airplane rolled into a spin. The airplane went out of view of the witness in a nose-down attitude of approximately 70 degrees. A friend of the pilot who was based at the airport said that when departing to the north as the pilot had done, there are limited options available for emergency landings. The fuel valve was found in the closed, or "off", position. Based on the length of the engine run up, the fuel selector was undoubtedly positioned correctly at takeoff and was most likely moved to the closed position by the pilot when he determined that a forced landing was inevitable. Post accident examination of the wreckage did not disclose any pre-impact mechanical anomalies. Due to damage sustained to the carburetor, no functional testing could be performed.

History of flight

On May 9, 2008, at 1645 Pacific daylight time, an experimental Thorp T-18, N8613A, collided with a residence following a loss of engine power during the initial takeoff from Crest Airpark, Kent, Washington. The pilot, who was also the registered owner of the airplane, was operating it under the provisions of 14 Code of Federal Regulations Part 91. The airline transport pilot, the sole occupant, was killed. The sole occupant of the residence was not injured. The airplane sustained substantial damage. Visual meteorological conditions prevailed and no flight plan was filed.

A witness reported his home is located about three-quarters of the way down runway 33. He had stepped out of his back door and heard the airplane departing. Initially, the engine sound was smooth. As it continued, the witness heard the engine running rough and when the airplane flew passed his hangar at about 300 feet above the runway, the witness saw two puffs of white smoke. The airplane appeared to have adequate airspeed and was still climbing, although the engine was cutting out. The engine then cut out completely and the airplane continued straight ahead for about 1 second. The airplane then entered a slow turn to the right, and when it had turned approximately 160 degrees, the right wing stalled and the airplane rolled into a spin. The airplane went out of view of the witness in a nose-down attitude of approximately 70 degrees.

A friend of the pilot was interviewed and indicated that he had known the pilot for 40 years. He had flown the accident airplane many times and he felt that it was a good airplane. The pilot's friend reported that the airplane had not flown since August of 2007. The pilot had the carburetor overhauled and had recently installed a new air inlet on the cowling. This was the first flight since the new items were installed. Prior to the flight, the pilot drained all of the old fuel out of the airplane and refueled the airplane. The pilot's friend stated that the pilot ran up the airplane prior to departure and no problems were identified. The engine had a supplemental type certificate (STC) for auto fuel and the pilot tested his fuel to ensure that there was no alcohol in it.

The pilot's friend had an airplane based at the airpark. He indicated that when taking off on runway 33 there are limited options for emergency landings. To the west of the airport there are houses. Straight ahead of the runway there are trees. To the east of the airport (the direction that the pilot was flying) there is a road and a couple of small fields. The pilot's friend said that there was no suitable landing area available when a loss of power occurred at a low altitude.

Personnel information

The pilot, age 69, held an airline transport certificate for multi-engine airplanes and a commercial pilot certificate for single-engine airplanes, as well as a certified flight instructor (multi-engine airplanes and instrument), ground, aviation maintenance technician- powerplant, flight engineer, and aircraft dispatcher certificates. His most recent medical certificate was a second class issued in March of 2008. It had the limitation that the pilot must wear corrective lenses.

The pilot reported approximately 8,400 hours of flight time on his last medical application.

Aircraft information

The Thorpe T-18 airplane was manufactured in 1969. The last condition inspection was completed on October 16, 2007, at a tachometer time of 257.9 hours. There were no airframe hours listed for the maintenance logbook entry. However, the previous condition inspection in August of 2006, showed a total airframe time of 3,302.5 hours.

Medical information

The King County Medical Examiner completed an autopsy on the pilot and attributed the cause of death to impact injuries sustained in the accident. The FAA Forensic Toxicology completed toxicological testing. The results were negative for carbon monoxide, cyanide, and volatiles. The results were positive for diphenhydramine (0.101 ug/ml, ug/g) in the blood, and diphenhydramine was also detected in the urine.

Tests and research

Federal Aviation Administration inspectors indicated that the airplane impacted a residence located east of the airpark. All control surfaces remained attached, and the wreckage was confined to the impact area. The fuselage was consumed in a post impact fire.

Investigators examined the wreckage following its recovery from the accident site. Examination of the airframe did not reveal any control system anomalies. The fuel system was traced from the fuel tank to the engine. The fuel valve was in the closed position.

A Textron Lycoming O-320-E2D engine powered the airplane. The crankshaft was rotated by hand using the propeller hub. Thumb compression was observed in proper firing order on cylinders 1, 3, and 4. The thumb compression on cylinder number 2 was weaker compared to the others. Mechanical continuity was obtained and there was no evidence of foreign object ingestion or detonation. The removal of cylinder number 2 showed no visible cracks on the cylinder head and the combustion chamber was undamaged. Each piston ring was secure and the valves were undamaged. The magnetos were removed and produced spark at all plug leads during hand rotation. The spark plugs were removed and the electrodes displayed coloration consistent with normal operation when compared with the Champion Spark Plugs "Check-A-Plug" chart AV-27.

The bottom portion of the carburetor was displaced from the engine; the top portion remained attached at the mounting pad. The float assembly was displaced from its mount and crushed. The fuel filter screen was free of visible contaminants. The air box, portions of the exhaust system, the starter, and the alternator were also displaced from the engine.

There was no evidence of pre-impact mechanical malfunctions observed.