Oconomowoc, WI, USA
UNREG
Claxton S-12
The un-registered airplane was destroyed when it impacted the ground following an engine failure after takeoff. The non-certificated pilot was fatally injured. A witness reported seeing the airplane and hearing the engine "quit". The airplane then made a series of gliding turns before it impacted into a marsh. The witness did not see the impact. Examination of the airplane showed no anomalies with respect to the airframe or control system. The engine's pistons exhibited scuffing and scoring indicative of a seizure. The marks on the piston contained carbon deposits indicating that the engine had experienced a seizure prior to the accident flight that had not been repaired.
HISTORY OF FLIGHT On September 12, 2004, about 1320 central daylight time, an un-registered amateur-built Claxton S-12, piloted by a non-certificated pilot, was destroyed when it impacted the ground near Oconomowoc, Wisconsin. The airplane was previously registered as N82000. The 14 CFR Part 91 personal flight was operating in visual meteorological conditions without a flight plan. The pilot, who was the sole occupant, was fatally injured. The flight had just departed from a private airstrip, and was en route to the Sylvania Airport, Sturtevant, Wisconsin. According to another pilot, he and the accident pilot departed from the private airstrip as a flight of 2 aircraft. He stated that he departed first and continued to the destination. This pilot reported that he was unaware that the accident had occurred until after he had completed the flight. A witness that lived near the accident site reported seeing an ultralight type airplane fly over his residence. He stated that a second ultralight airplane was about 1/2 mile behind the first one. He stated that the second airplane was flying south over highway P and he heard the engine "quit". He stated that there was no engine sound and that the airplane made a left turn to the east with not much change in altitude. He said that the airplane headed east for about 100 yards and then made another left turn to the north. At this time, the airplane was starting to lose altitude. The witness stated that he was concerned for his safety since the airplane was heading toward him so he took cover behind a large tree. He said that he heard the impact and then looked and saw the tail of the airplane "sticking out of the marsh". PERSONNELL INFORMATION The pilot did not possess a pilot certificate issued by the Federal Aviation Administration (FAA). No records were found with respect to the pilot having applied for a FAA medical certificate or FAA student pilot certificate. AIRCRAFT INFORMATION The airplane was a kit-built airplane powered by a 65 horsepower Rotax 582 engine. According to the kit manufacturers published information, the airplane had accommodations for 2 occupants and an empty weight of 475 pounds. Research indicated that the airplane had previously been registered as an amateur-built airplane. METEOROLOGICAL INFORMATION At 1245, the recorded weather at the Waukesha County Airport, near Waukesha, Wisconsin, was: Winds 190 degrees at 4 knots; Visibility 10 statute miles; Sky condition 6,000 feet scattered; Temperature 29 degrees Celsius; Dew point 14 degrees Celsius; Altimeter setting 30.14 inches of mercury. WRECKAGE AND IMPACT INFORMATION The airplane impacted a marsh area. The wreckage was contained to the immediate area of the initial impact point. The FAA examined the wreckage subsequent to its removal from the accident site by local authorities. No pre-impact anomalies were found with respect to the airframe or airplane control system. The engine was examined and both pistons exhibited scuffing and scoring on the outside diameter. The marks were linear and in the direction of piston travel and exhibited carbon deposits. MEDICAL AND PATHOLOGICAL INFORMATION An autopsy of the pilot was performed by the Waukesha County Medical Examiner's Office. A Final Forensic Toxicology Fatal Accident Report prepared by the FAA listed the following findings: 0.041 (ug/ml, ug/g) BENZOYLECGONINE detected in Blood 0.031 (ug/ml, ug/g) BENZOYLECGONINE detected in Liver 0.021 (ug/ml, ug/g) PAROXETINE detected in Blood 0.102 (ug/ml, ug/g) PAROXETINE detected in Liver Benzoylecgonine is the inactive substance to which cocaine is primarily converted in the body. Paroxetine is a prescription antidepressant, often known by the trade name Paxil. In addition to depression, the medication is used to treat obsessive-compulsive disorder, panic attacks, and social anxiety disorder. ADDITIONAL INFORMATION An ultralight news website (www.ultralightnews.ca) indicated the liquid-cooled Rotax engines, such as the accident airplane's engine, have experienced "cold seizures." Seizures occur when the piston expands due to heat faster than the cylinder bore, reducing the clearance between the two. The website stated that the results of a seizure incident can range from a momentary loss of power to complete engine stoppage. The website indicated that after a seizure incident, the engine may start and appear to be operating normally after it is allowed to cool, but the engine is now more susceptible to another seizure. The website stated that a seizure resulting in complete engine stoppage can result from un-repaired damage from previous seizure occurrences.
The loss of engine power due to the seizure of the pistons and the pilot's failure to maintain airspeed which resulted in an inadvertent stall. The previous damage to the pistons due to earlier seizure occurrences was a factor.
Source: NTSB Aviation Accident Database
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