NTSB Identification: LAX07LA142.
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Accident occurred Sunday, April 29, 2007 in Marysville, CA
Probable Cause Approval Date: 05/28/2008
Aircraft: McDonald J4B-2, registration: N445SM
Injuries: 1 Fatal.

NTSB investigators may not have traveled in support of this investigation and used data provided by various sources to prepare this aircraft accident report.

During cruise flight, witnesses in several different locations reported hearing a loud "pop" emanate from the gyrocopter and then it spiraled to the ground in a nose down attitude. One witness reported that the gyrocopter's nose was pushed up after it was struck by a gust of wind. He watched as the pilot corrected the pitch attitude by pushing the nose down. He then saw the gyrocopter tilting back and forth. A friend of the pilot, who is also the gyrocopter kit manufacturer, reported that he and the pilot had performed a pitch change adjustment to the main rotor system that was about 1/4 inch out of track. After the adjustment was made, the friend test flew the gyrocopter with no problems encountered. The gyrocopter was constructed of a tandem seat configuration fuselage with tricycle landing gear, a two-bladed teetering main rotor system, a rear mounted engine with a three-bladed propeller assembly, followed by a rudder, and vertical and horizontal stabilizers. An inspection of the gyrocopter by a Federal Aviation Administration (FAA) inspector and the gyrocopter kit manufacturer revealed that only about 5 percent of the wooden three-bladed propeller remained affixed to the propeller hub. Reconstruction of the recovered propeller material found that one of the propeller blades had a deep concave deformity at the leading edge approximately 10 inches from the root. No evidence of propeller blade or main rotor blade to airframe contact was found, and the investigation could not explain the origin of the propeller blade defect nor its relationship to the accident's causation, if any. Toxicological tests revealed the presence in the blood of zolpidem (a prescription sleep aid) at a level consistent with very recent use, and very high blood levels of hydrocodone (a prescription narcotic painkiller), and diphenhydramine (an over-the-counter antihistamine). All three medications would have been expected to result in impairment of judgment and psychomotor skills. The pilot's ability to operate the gyrocopter with the levels of substances found suggests a substantial tolerance to their sedative effects, implying a long-term use of high doses. The pilot had not held a current FAA medical certificate in over 25 years.

The National Transportation Safety Board determines the probable cause(s) of this accident to be:

An in-flight loss of control for undetermined reasons. Contributing to the accident was the impairment of the pilot by the drug substances identified in the toxicological testing.

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