CESSNA P210N — Buffalo, WY

What happened

The pilot departed on a visual flight rules (VFR) cross-country flight. Recorded automatic dependent surveillance – broadcast (ADS-B) data showed the airplane ascended to a cruise altitude of 17,450 ft mean sea level (msl) where it remained for about 9 minutes, 17 seconds until a descent was observed. The data showed the airplane descended 2,050 ft in 12 seconds, followed by brief 175 ft ascent. The airplane then descended 1,075 ft during the final 4 seconds of ADS-B data, which equated to about a 12,000 ft-per-minute descent rate. The last recorded ADS-B target was located about .46 miles northwest of the accident site, about 5,680 ft above ground level (agl).

A witness located about 4 miles south of the accident site reported that they heard the airplane and it sounded fine until they heard a distinct over-rev of the engine, followed by the sound of the impact. Fire crews were responding to reports of a wildland fire when they located the wreckage of the airplane in rugged mountainous terrain.

Based on High-Resolution Rapid Refresh (HRRR) sounding and satellite imagery, the airplane most likely encountered instrument meteorological conditions (IMC) with moderate and greater convectively induced turbulence during the last 5 minutes before the accident.

Postaccident examination of the recovered wreckage revealed no evidence of any preexisting mechanical malfunction that would have precluded normal operation. The outboard 65 inches of the right wing was not located within the recovered wreckage. Given the high descent rate recorded during the final few seconds of the flight, coupled with the missing section of the wing, it’s likely that the airplane broke up in flight following an encounter with moderate or greater turbulence while in IMC.

The autopsy examination was limited by the condition of the pilot’s body so it could not be determined if there may have been an impairing or incapacitating event. While the impairing anxiolytic medication diazepam and its metabolites were found in liver tissue, there were no blood specimens available to determine if the medication was at a therapeutic level. Thus, whether the pilot’s medical conditions and effects from his use of diazepam were a factor in this accident could not be determined from the available medical evidence.

An editorial "what led to it / how to avoid it" analysis for this accident is generated separately and will appear here.