CEN21FA007

The airplane departed on a visual flight rules cross-country flight from a high-elevation (9,078 ft mean sea level) airport. Automated dependent surveillance-broadcast (ADS-B) data showed that the airplane proceeded east into a box canyon with rising terrain. The data showed that, before entering the box canyon, the airplane did not climb toward the west, where there was lower terrain. The data also showed that the airplane was in a gradual climb for about 8 miles into the canyon and that the airplane then made a right turn to the south just before impacting terrain. No known radio distress calls were received from the pilot. The airplane wreckage showed evidence of a nearly vertical impact. Postaccident examination found no preimpact anomalies with the airframe, engine, flight controls, and propeller. Flight control continuity was confirmed from the cockpit to all flight control surfaces. The elevation of the accident site was 11,823 ft mean sea level. The surrounding terrain to the north, east, and south was higher than the accident site elevation, with peaks ranging from about 12,000 to 14,000 ft. In addition, the calculated density altitude in the area of the accident site was about 13,604 ft, which would have diminished the airplane’s climb performance. There was no significant turbulence in the area. Thus, the pilot likely turned the airplane toward higher terrain and into the box canyon before the airplane could gain enough altitude to traverse the high terrain, resulting in a loss of control.

Weight and balance calculations showed that the airplane, including the full fuel tanks, the two occupants, and all baggage, was about 300 pounds under maximum gross takeoff weight. On October 5, 2020, about 1304 mountain daylight time, a Beech S35 airplane, N4444K, was substantially damaged when it was involved in an accident near Telluride Regional Airport (TEX), Telluride, Colorado. The pilot and passenger sustained fatal injuries. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. The airplane departed on a planned visual flight rules cross-country flight from runway 27 at TEX. Automated dependent surveillance-broadcast (ADS-B) data showed that the airplane had a normal takeoff and made a subsequent left turn toward the east. The airplane proceeded east into a box canyon and an area of rising terrain. The data showed that, before entering the box canyon, the airplane did not maneuver toward the west, where the terrain was lower than the surrounding terrain. The data also showed that the airplane was in a gradual climb for about 8 miles into the canyon and that the airplane then made a right turn to the south, which was immediately followed by the airplane’s impact with terrain. See figures 1 and 2. No known radio distress calls were received from the pilot after takeoff. Figure 1. ADS-B flight track from TEX to the accident location. Figure 2. ADS-B final portion of flight track. An autopsy on the pilot was performed by the Division of Forensic Pathology, Montrose Memorial Hospital, Montrose, Colorado. His cause of death was multiple traumatic injuries. Toxicology tests performed by the Federal Aviation Administration (FAA) Forensic Sciences Laboratory were negative for drugs and alcohol. An unmeasured amount of fexofenadine (Allegra) and its metabolite, azacyclonol, were detected in the pilot’s specimens. Fexofenadine (which is also known as Allegra) is a nonsedating antihistamine used to treat allergies and is acceptable for pilots to use. The calculated density altitude was about 13,747 ft at the accident site. The freezing level was just above 17,000 ft with no structural icing conditions. Light-to-moderate turbulence was generally indicated near the accident site. The pilot was a professional commercial air carrier pilot. The available evidence did not show the amount of high-altitude mountain flying experience that the pilot had accumulated in single-engine airplanes. The accident site was located in rugged mountainous terrain about 8 miles east of TEX. The elevation of the accident site was 11,823 feet msl. The surrounding terrain to the north, east, and south was higher than the accident site elevation, with peaks ranging from about 12,000 to 14,000 ft. The airplane wreckage showed evidence of a nearly vertical impact. Most of the forward section of the fuselage was crushed, and both wings showed impact damage across the leading edges of their spans. Flight control continuity was confirmedfrom the cockpit to all flight control surfaces. All structural damage to the airplane was consistent with ground impact. The airplane structures and flight controls showed no evidence of preimpact anomalies. Engine continuity was confirmed. Torsional break of the propeller flange was consistent with rotation at impact. All physical damage to the engine was consistent with ground impact; no preimpact anomalies were found. Two of the three propeller blades were recovered. All physical damage to the two recovered propeller blades was consistent rotation at ground impact. The third blade’s hub attachment showed impact damage, and the hub showed no evidence of a preimpact failure.