Flight History
On August 9, 2022, about 1106 Pacific daylight time, a Sonex Aircraft Waiex airplane, N51YX, was destroyed when it was involved in an accident near Maxwell, California. The pilot sustained fatal injuries. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight.
According to family members, the purpose of the flight was personal and the exact route was unknown. Automatic Dependent Surveillance–Broadcast (ADS-B) data showed that the experimental airplane departed runway 13 at Colusa County Airport (O08), Colusa, California. The airplane traveled north of Colusa, then west, crossing Highway I-5, and then north of Maxwell, where the ADS-B data terminated in a remote agricultural area. The airplane came to rest nose down in a flat dirt field. The wreckage, which was destroyed, sustained fire damage.
The airplane was equipped with a Dynon FlightDEK-D180 unit that recorded about 22 minutes of data from engine start. A review of the data showed that shortly before the data ended, the airplane transitioned from a straight and level attitude to a nose down attitude. Engine parameters did not show any signatures consistent with a loss of engine power.
Personnel Information
Family members reported that the pilot had been flying for over 30 years with various breaks. The pilot had no reported concerns with the airplane and recently felt “really comfortable” operating it. The pilot purchased the airplane with a partner about 1 year before the accident. According to his logbook, he had flown the airplane 26.2 hours, of which 20.0 hours were with a flight instructor.
Aircraft Information
Federal Aviation Administration (FAA) records showed that the pilot and another individual purchased the airplane from the builder in September 2021. Maintenance records indicated a new CAMit 33SLRE reciprocating engine was installed in June 2016.
Meteorological Information
The estimated density altitude for the closest meteorological reporting station was 1,561 ft above mean sea level.
Wreckage and Impact Information
A postaccident examination revealed flight control continuity from the cockpit to the empennage and from the wings to the cockpit. Cockpit flight controls were destroyed by fire damage, but hardware appeared intact. The breached fuel tank and fuel lines were also destroyed by fire.
The engine, which sustained impact damage, was examined. The crankshaft flange could be rotated by hand, confirming internal continuity. Rocker arm movement was confirmed on all cylinders. Pistons moved within cylinders, and accessory gears moved when the propeller remnant was rotated. The wood propeller was destroyed in the impact sequence.
The examination discovered no preimpact mechanical malfunctions or failures with the airframe or the engine. No fire damage specifically related to an in-flight fire was found.
Additional Information
The FAA has published Advisory Circular 90-109A, Transition to Unfamiliar Aircraft, which classifies the Sonex Aircraft Waiex as having light control forces and/or rapid airplane response, along with nontraditional and/or unfamiliar airplane system operations. The document notes that without training, a pilot may over-control the airplane, potentially leading to loss of control or structural failure. It also discusses the risks of system mismanagement in customized experimental airplanes.
Medical and Pathological Information
The pilot’s autopsy report listed his cause of death as high-velocity acceleration-deceleration polytrauma and manner as accident. Structural evaluation of the brain, heart, and lungs was limited due to injury extent. Trachea and bronchi showed no evidence of smoke inhalation.
Toxicological testing detected ethanol in liver, lung, kidney, and heart tissues at various concentrations. N-propanol was found in lung, kidney, and heart tissue. Ondansetron was detected in liver tissue. No urine, vitreous fluid, or suitable blood was available for testing.
The pilot had previously been treated for esophageal cancer with surgery in 2013.