Cessna 182 N52743 accident near Mackay, Idaho

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 analysis

The pilot reported that, while flying in mountainous terrain around 9,500 ft mean sea level (700 to 1,200 ft above the ground), the airplane 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 airplane was unable to climb, and it then impacted wooded, snow-covered terrain along the mountainside.

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 ft. According to the Federal Aviation Administration 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.

Text from the NTSB. Open the NTSB docket for GAA17CA202 for the full record.