History of Flight
On August 13, 2015, at about 0930 Pacific daylight time, a Cessna T182T (registration N6289Z) was destroyed when it impacted terrain while maneuvering near Oroville, Washington. The pilot, who was the registered owner, and a pilot-rated passenger sustained fatal injuries. The flight was operated under 14 CFR Part 91 as a personal cross-country trip. Visual meteorological conditions prevailed, and no flight plan was filed. The flight departed Dorothy Scott Airport (0S7) in Oroville around 0920, with an intended destination of Spokane International Airport in Spokane, Washington.
About 0945, the Okanogan County Sheriff's department received a report of a forest fire near Oroville. Upon arrival, personnel discovered a destroyed airplane, which was not immediately identified. On August 14 at 0031, an Alert Notification (ALNOT) was issued after family members became concerned when the pilot did not arrive at his destination. Later that day, the wreckage found by the sheriff's department was confirmed to be the missing airplane. No witnesses to the accident sequence were reported.
Personnel Information
It could not be determined which pilot occupied which seat or which pilot was manipulating the flight controls at the time of the accident. The pilot/owner, age 88, held a private pilot certificate with single-engine land and instrument ratings. A third-class medical certificate was issued on February 17, 2015, with the limitation: must use hearing amplification. On his most recent medical application, he reported 1,701 total flight hours. His personal logbook was not obtained. The pilot-rated passenger was a Canadian citizen; no flight information was provided.
Aircraft Information
The four-seat, single-engine, high-wing, fixed landing gear airplane (serial number T18208870) was manufactured in 2008. It was powered by a Lycoming TIO-540-AK1A engine rated at 235 horsepower and equipped with a McCauley three-bladed constant-speed propeller (model and serial number not determined). The most recent annual inspection was completed July 14, 2015, at a total airplane and tachometer time of 295.5 hours.
Meteorological Information
The National Weather Service Surface Analysis Chart for 0800 depicted a low pressure center in southern Washington with a trough stretching from British Columbia southward. Station models showed calm and light variable winds. A weather observing station at Osoyoos, British Columbia, reported at 0900: wind calm, temperature 23°C, dew point 14°C. A North American Mesoscale model sounding indicated light and variable winds below about 6,000 feet, with southwesterly winds of 15 to 20 knots above that level. The atmosphere was dry, with relative humidity at or below 41%. No significant turbulence was identified, and the freezing level was at 14,300 feet. No pilot reports were made within 2 hours of the accident. GOES-15 satellite imagery showed mostly clear skies. No AIRMET or SIGMET advisories were active for the accident location.
Wreckage and Impact
The accident site was on a hillside at an elevation of 3,093 feet msl. The wreckage was spread along a 68-foot-long up-sloping path through a ponderosa pine forest on a 168-degree magnetic heading. The first identified point of impact was a pine tree broken off about 70 feet above ground, showing a 45-degree angle cut. The right wing tip, a section of the right wing, the right aileron, and the right flap were found about 43 feet southeast of the first impact point, all charred and melted. The main wreckage—including the engine, propeller, cabin, left wing, both main landing gear, baggage compartment, aft fuselage, and empennage—came to rest inverted, oriented southeast on a magnetic heading of about 128 degrees. These components were largely consumed by fire.
Additional Information
The fuel selector valve was examined at the NTSB Materials Laboratory. A black, rigid material was found inside its inlet; analysis indicated the material was likely decomposed to elemental carbon and water due to high temperature, and its original identity could not be determined.
The airport manager observed the airplane depart from runway 33. He noted that instead of flying southbound through the valley, the pilot turned eastbound towards rising terrain at about 400 feet agl. He also stated that when he previously flew with the owner/pilot, the pilot had a tendency to engage the autopilot right after takeoff and was not familiar with the instrumentation panel, particularly how to set vertical speed on the autopilot.
A family member disclosed that in recent years, the owner/pilot did not fly alone and conducted about two flights per year. A family friend stated that the owner/pilot purchased the airplane about 3 years prior and that it was "too much of the airplane" for him.
Medical and Pathological Information
Autopsies on the pilot and passenger were performed on August 25, 2015, by the Okanogan County Coroner's Office. The cause of death for both was determined as "blunt force trauma and thermal injuries due to aircraft collision with ground." The FAA Civil Aeromedical Institute performed toxicology tests. For the pilot, no volatiles were detected in blood; however, diphenhydramine and propranolol were detected. Tests for cyanide and carbon monoxide were not performed. For the passenger, ethanol was detected in muscle, but no drugs were detected; cyanide and carbon monoxide tests were also not performed.
Tests and Research
The airframe was examined on August 15, 2015. Most of the airplane was consumed by post-crash fire. The right wing flap was thermally damaged; the flap actuator extension measured 3/16 inches, indicating flaps were in the full up position. Control cables exhibited tension overload separations. The aileron control cable continuity was confirmed from the cockpit to each surface. The propeller hub showed impact and thermal damage; blade No. 1 exhibited tip twisting toward the non-camber side, while blades No. 2 and No. 3 had nicks but no significant twisting. The fuel selector valve was ported to the left wing fuel tank; the right wing fuel port was obstructed with an unidentified charred substance. The elevator trim actuator extension corresponded to 15 degrees trailing edge up. No evidence of pre-impact mechanical anomalies was observed.
The engine was examined on September 10, 2015. All six cylinders remained attached except No. 6, which broke off at the piston head. Spark plugs showed varying coloration, with some oil contamination and corrosion. Magnetos could not be tested due to thermal damage. The crankshaft could not be manually rotated. The turbocharger showed no signs of foreign damage. No evidence of pre-impact mechanical anomalies was observed with the engine.