The pilot reported that, while flying in mountainous terrain around 9,500′ mean sea level (700′ to 1,200′ above the ground), the Cessna 182 encountered a downdraft.
He added that he immediately turned away from the mountainside in a right turn, added full power, selected 10º of flaps, and pitched the nose up to maintain the airplane’s maximum angle-of-climb airspeed (Vx).
Subsequently, the plane was unable to climb, and it hit wooded, snow-covered terrain along the mountainside near Mackay, Idaho.
The fuselage and both wings sustained substantial damage.
The pilot reported that there were no preaccident mechanical malfunctions or failures with the airplane that would have precluded normal operation.
The calculated density altitude near the flightpath was about 10,339′. According to the FAA Koch Chart, the airplane would have experienced a 50% decrease to the normal climb rate. The high-density altitude conditions likely contributed to the airplane’s inability to establish a climb.
Probable cause: The pilot’s decision to maneuver the airplane over mountainous terrain in high-density altitude conditions, which resulted in the airplane’s inability to maintain altitude or establish a climb.
NTSB Identification: GAA17CA202
This March 2017 accident report is provided by the National Transportation Safety Board. Published as an educational tool, it is intended to help pilots learn from the misfortunes of others.