NTSB investigators either traveled in support of this investigation or conducted a significant amount of investigative work without any travel, and used data obtained from various sources to prepare this aircraft accident report.
The commercial pilot and two passengers were on a personal cross-country flight that included flying through a narrow mountain pass. The typical route through the pass required making multiple turns, and the pass intersected with a box canyon. A family member reported the airplane overdue for arrival, and an alert notice was issued. The airplane’s wreckage was located the following day at the bottom of the box canyon.
A pilot who flew through the mountain pass on the morning of the accident reported 4,400-foot ceilings, severe turbulence, and flat light conditions. A friend of the pilot who attempted to cross the mountain pass the day of the accident reported flat light conditions and having difficulty discerning terrain features. He turned the airplane around due to the weather conditions and returned to the airport. He also stated that the accident pilot had become disorientated the previous year while flying a helicopter through the same mountain pass and had taken the wrong route.
A postaccident examination revealed no evidence of a mechanical malfunction or failure with the airframe or engine that would have precluded normal operation. Given the lack of mechanical anomalies, the reported weather conditions, and the pilot statements, it is likely that the accident pilot mistakenly entered the box canyon thinking it was his route. Additionally, wreckage impact signatures and GPS data indicated that it is likely that the pilot was attempting to avoid rising terrain by entering a steep bank turn, which resulted in an aerodynamic stall.