N94262Cessna 210L · 1974

On September 4, 2019, about 1521 mountain daylight time, a Cessna 210L airplane, N94262, was substantially damaged when it was involved in an accident near Henefer, Utah. The two commercial pilots were fatally injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 aerial observation flight.

The operator reported that the pilot was giving a pipeline patrol orientation flight to a new-hire pilot. According to the operator, the pilot was familiar with the area of the accident site and had routinely flown there to conduct aerial pipeline inspections. When the pilots did not return as planned, a Federal Aviation Administration (FAA) Alert Notice (ALNOT) was issued, and the wreckage was located the following morning in a mountain canyon about 5 miles west of Henefer, Utah.

Company-provided flight tracking data (Spidertracks) indicated that the airplane departed from Evanston-Utica County Airport (EVW), Evanston, Wyoming, about 1455 and proceeded roughly southwest, flying much of the flight over a valley at or near the altitude of surrounding terrain. The airplane turned west, then southeast into a canyon. At 1521, the last recorded data point indicated that the altitude was 6,208 ft mean sea level (msl), the direction of flight was 122°, and the airspeed was 126 mph.

An onboard GPS unit also contained data from the accident flight, which closely matched the Spidertracks data; however, the GPS data showed a 135° left turn near the end of the data that was not recorded by Spidertracks. The last recorded GPS point was at 1521:14, and showed the airplane at 5,998 ft msl, at a ground speed of about 120 mph. The last recorded Spidertracks data point was about 0.7 mile southeast of the last recorded GPS point.

Tracking data revealed that the airplane flew below the company minimum altitude of 500 ft above ground level (agl) during the pipeline patrol portion of the flight, several times to altitudes as low as about 300 ft agl. During the last portion of the flight, the airplane was at or above the minimum altitude of 500 ft agl specified in the company’s operations manual.

The pilot held a commercial pilot certificate with airplane single-engine land, airplane multiengine land, and instrument airplane ratings. The pilot was issued an FAA first-class airman medical certificate on June 19, 2019, with a limitation for corrective lenses. On the application for that medical certificate, the pilot reported 1,404 total hours of flight experience and 562 hours in the previous six months. The pilot’s logbook was not located during the investigation.

The new-hire pilot held a commercial pilot certificate with airplane single-engine land and instrument ratings. The pilot was issued a FAA second-class airman medical certificate on November 1, 2018, with no limitations, at which time he reported 350 total hours of flight experience and 100 hours in the previous six months.

The high-wing airplane was built in 1975. It was powered by a 375-horsepower Continental IO-520-L reciprocating engine driving a three-bladed, composite, constant-speed propeller.

According to information provided by the operator, the airplane’s most recent annual inspection was completed on January 2, 2019. A 500-hour company inspection was completed on August 26, 2019. At the time of this inspection, the airplane had accumulated a total of 13,727.6 hours of operation.

At 1448, the weather observation facility at Hill Air Force Base, Utah, located about 20 miles west northwest of the accident site, reported wind from 310° at 4 knots, 10 statute miles visibility, few clouds at 8,000 ft, temperature 32ºC, dew point 5ºC, and an altimeter setting of 30.12 inches of mercury.

No significant weather or mountain wave conditions were reported or forecast in the accident area, and no AIRMETS, SIGMETS, or CWAs were valid in the area at the time of the accident. The surface wind speed was estimated to be about 10 to 15 knots.

Given the atmospheric conditions on the day of the accident, the density altitude at the accident location was calculated to be about 9,778 ft.

The high-wing airplane was built in 1975. It was powered by a 375-horsepower Continental IO-520-L reciprocating engine driving a three-bladed, composite, constant-speed propeller.

According to information provided by the operator, the airplane’s most recent annual inspection was completed on January 2, 2019. A 500-hour company inspection was completed on August 26, 2019. At the time of this inspection, the airplane had accumulated a total of 13,727.6 hours of operation.

All major structural components of the airplane were located at the accident site. The site was located on a canyon hillside at an elevation about 6,553 ft msl, about 150 ft below the top of a ridgeline and surrounded by mountainous terrain. The initial impact point, identified by a large area of disturbed terrain, was located about 30 ft before the main wreckage. The disturbance measured about 22 ft long by 9 ft wide. Small fragments of the airplane and propeller blade tips were found at the initial impact point.

The fuselage came to rest upright on a magnetic heading of about 345°. The flaps and landing gear were retracted. Some residual fuel was observed in the fuel tanks and a strong odor of fuel was present. The airplane’s bank indicator showed the airplane in about a 35° left bank.

The three-bladed propeller had separated from the crankshaft and was located about 10 ft from the main wreckage with all blade tips observed separated. One blade was loose at the hub. Chordwise scratches and gouges were observed. The two remaining blades were bent forward about 6 inches from the tip and exhibited light scratching.

The airframe and engine were examined at a nearby facility. Continuity of the flight controls was established. The crankshaft was rotated by hand and rotational continuity was established throughout the engine and valve train to all cylinders. A borescope inspection of the cylinders revealed normal operating signatures. The examination revealed no evidence of pre-impact mechanical anomalies or malfunctions that would have precluded normal operation.

The Utah Department of Health Office of the Medical Examiner, Taylorsville, Utah, conducted autopsies on the pilots. The medical examiner determined that the cause of deaths were blunt force injuries.

The FAA's Forensic Sciences Laboratory performed toxicological testing on the pilots. For the pilot, testing was negative for carbon monoxide and volatiles and tested for drugs, except for phentermine. Phentermine is prescription anti-obesity medication used for a limited period to speed weight loss in overweight individuals who are exercising and eating a low-calorie diet. Potential adverse side effects include heart palpitations, elevated blood pressure, and restlessness. This medication may be misused for performance enhancement and relief of fatigue and has abuse potential. Phentermine is in a class of medications called anorectics, and its use by pilots is not recommended.

Testing for the recently hired pilot was negative for carbon monoxide, volatiles, and tested-for drugs except for a small amount of ethanol in cavity blood and urine, but not vitreous, consistent with post-mortem production.