A pilot’s failure to follow established mountain flying guidance is listed as the probable cause of a May 6, 2023, plane crash that killed four widely-known Florence residents, according to the National Transportation Safety Board’s aviation investigation final report released Feb. 5.
The failure to follow the guidance resulted in a loss of control and impact with trees and mountainous terrain, the report states. Contributing to the accident was the airplane’s reduced climb performance at the elevated density altitude and the presence of moderate turbulence as forecasted.
The bodies of Bruce Claremont, Laurie Aves, and Roger and Kathrine Duncan were located on May 7, 2023, after a search in the area where the plane had crashed.
Claremont, the pilot and owner of the plane, and his passengers departed Fremont County Airport at about 9:20 a.m. May 6, 2023, en route to Centennial Airport in Englewood. The final data point was recorded about 10 minutes later when the airplane was about 15 miles from the departure airport at an altitude of 9,400 ft msl. This was about 0.20 miles from the accident site, crash investigation reports state.
The accident site was in mountainous terrain about 15 miles north of the departure airport at an elevation of about 9,170 ft. Terrain in the immediate vicinity of the accident site rose to nearly 9,300 ft.
According to records, the airplane came to rest inverted after impacting trees and terrain. A post-impact fire ensued that consumed the majority of the fuselage. No anomalies attributable to a preimpact failure or malfunction were observed.
The report states the expected climb performance for the airplane at maximum gross weight and a pressure altitude of 10,000 ft was 450 fpm with the engine at full throttle. At 12,500 ft pressure altitude, the expected climb rate decreased to 330 fpm. This was about one-half to one-third the expected climb rate at sea level.
The FAA publication Tips on Mountain Flying suggested maintaining at least 1,000 ft terrain clearance when navigating a mountain pass or crossing a ridge line. If the wind is above 20 knots, the guidance recommended pilots increase terrain clearance to 2,000 ft to avoid most of the turbulence and downdrafts. The information also noted that at higher density altitudes, the airplane’s rate of climb and actual service ceiling are decreased.
According to FAA records, the airplane was assembled from spare parts and certificated in the experimental exhibition category in April 2012. The airplane was originally manufactured as a Cessna model R-172E and sold to the U.S. Army as a model T-41B. The owner informed the FAA that he did not know the disposition of the military data plate, nor did he have any military records for the airplane.
Claremont had a flight time of 850 hours. Toxicological testing identified acetaminophen and aspirin, neither of which are considered impairing.
Laurie Aves had lived in Florence for about nine years and, in that time, had become a well-known activist and thread of the community. She was constantly active in the community and a business owner of many Main Street buildings, including the Aspen Leaf Bakery and Cafe, the Mezzanine Antiques and Collectibles, and the Antique Warehouse. She also was a constant donor to local scholarships for students struggling to attend vocational schools and similar interests and put the needs of her community first.
The Duncans had been in the area for approximately six years and, like Aves, had set themselves apart as dedicated business people and proponents for a better Florence. The Husky Burger, Two Scoops Ice Cream Parlor, Florence Lanes, Two Sisters Restaurant (which has since moved to Penrose), and several other buildings around town were owned by the Duncans.
Claremont was a resident of Florence for more than 20 years and owned the tech business Migration Specialties. A gifted software and hardware engineer, Claremont worked to develop Migration Specialities into a successful business and, according to the business’s website, “products and services are available worldwide. Our business focuses on preserving important software while upgrading the legacy hardware that supports it. We offer remote and onsite delivery options.”
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