Incident Sequence
According to communications, the pilot reported to air traffic control that he was descending from 13,500 feet to 11,500 feet. Upon passing 11,500 feet, the pilot indicated he was continuing the descent to 9,500 feet. No further transmissions were received from the pilot.
Radar data showed the aircraft descending normally until it passed through 10,000 feet. At that point, the descent rate increased dramatically, and the aircraft was lost from radar at 5,200 feet.
Eyewitness Observations
Witnesses on the ground observed the aircraft in normal flight at approximately 10,000 feet. They then reported seeing the aircraft's wing rock back and forth, after which the aircraft nosed over and began a vertical descent. The engine was heard operating at high rpm until the aircraft impacted the ground.
Postcrash Examination
Examination of the wreckage revealed that all components necessary for flight were located on or around the main wreckage site. Investigators found no evidence indicating any pre-existing failure or malfunction of the aircraft structure, flight controls, or engine. Additionally, no evidence of in-flight bird contact was discovered.
Manufacturer's Input
The kit manufacturer for the aircraft reported that they have not observed any stability or control problems that would lead to an uncontrolled vertical descent.
Pilot Background
Before the flight, the pilot was reported to be in good health and good spirits.