HISTORY OF FLIGHT On October 1, 1994, at 0942 central daylight time, a McMurtrie Jurca MJ-10, N379SF, was destroyed when it impacted terrain while maneuvering at the Bartlesville, Oklahoma, Municipal Airport. The airline transport rated pilot was fatally injured. Visual meteorological conditions prevailed. The following is collectively based on four written witness statements. The aircraft took off, the landing gear was retracted, and the aircraft remained in the traffic pattern. On base leg, the landing gear was lowered; however, the left main gear did not appear to extend completely. The landing gear eventually was completely lowered; however, the airplane was halfway down the runway. The engine was heard to increase power as if the pilot was attempting to make a go-around. The airplane pitched up to a nose high attitude, stalled, the left wing dropped, and the airplane dove to the ground. One witness said the airplane made a "3/4-spin before impact." During the investigation a video tape was provided to the investigator-in-charge to review. Although the last few seconds of the accident was not videotaped, the take off and cycling of the landing gear was captured and the engine sounds could be heard. The pilot's brother, who assisted in building the airplane and who also witnessed the accident, stated that on a previous test flight several months earlier, the pilot was forced to execute a forced landing following an uncommanded propeller feathering. He further stated that it appeared to him that the propeller had again feathered. AIRCRAFT INFORMATION According to the aircraft maintenance records, the propeller was overhauled on December 1, 1992, and had not been used until it was installed on N379SF. Maintenance records further indicated the propeller governor was replaced on July 22, 1994. WRECKAGE AND IMPACT INFORMATION The accident site was located abeam, and approximately 150 feet to the right, of the departure end of runway 17. The first wreckage noted was the airplane's propeller, located just outside the ground fire area, and 6 feet to the right of the wreckage distribution centerline. All but one blade remained attached to the hub, and the hub remained attached to the gearbox. The third propeller blade was located nearby. In close proximity to the propeller were three ground disruptions. The first disruption, arbitrarily labeled the 12 o'clock position, measured 47 inches in length. The second disruption at the 3 o'clock position measured 84 inches in length. The third disruption at the 9 o'clock position measured 44 inches in length. Actual measurement from the propeller blade tip to the center of the hub was 45 inches. There was a ground scar 18 feet, 10 inches long. At the beginning of this scar were red lens fragments. The scar terminated at the ground indentation containing the propeller hub. The main body of wreckage lay 55 feet beyond, aligned on a magnetic heading of 275 degrees. The left wing, although still attached to the fuselage via cables, was bent back 30 degrees. Both wings bore fire damage, particularly in the area of the fuel tanks. MEDICAL AND PATHOLOGICAL INFORMATION An autopsy (T-374-94) was performed by the Oklahoma State Medical Examiner's Office. Toxicology protocol, conducted by FAA's Civil Aeromedical Institute (CAMI), revealed the presence of pseudoephedrine in blood and liver fluid. According to a CAMI spokesman, pseudoephedrine is a common over-the-counter nasal decongestant, and is not contraindicated for flying. TESTS AND RESEARCH The McCauley propeller was disassembled and examined at their Vandalia, Ohio, facilities under the supervision of a FAA maintenance inspector. According to the McCauley report, "Several impact marks found on propeller components indicate a blade angle range at impact of 40 degrees to 45 degrees, measured at the 30 inch reference station. The blade angle range is considered high for a slow speed impact... It is possible that the configuration's output control pressure was not capable of maintaining blade angle, and that the propeller was slipping to coarse pitch prior to impact. (This would be) possible if the propeller, governor, oil transfer bearing, and oil flow output, were not compatible for this installation, or, if an oil pressure leak in the transfer system occurred." Wreckage examination disclosed no evidence of oil leaks. The Woodward propeller governor was disassembled and examined at their Rockton, Illinois, facility under the supervision of an FAA maintenance inspector. According to the Woodward report, there were "no anomalies in appearance or function," and the unit was "operational in all conditions." ADDITIONAL INFORMATION At the conclusions of these tests mentioned above, the wreckage andvarious components were returned and verbally released to the owner's representative. A written release, dated January 23, 1995, was sent to the owner's representative but was never returned.