Cessna 180 N9455C accident near Puntilla, Alaska

Probable cause

The airplane’s encounter with a downdraft while maneuvering at a low altitude, which resulted in the exceedance of the airplane’s critical angle of attack and a subsequent aerodynamic stall.

NTSB analysis

According to the pilot, he made two passes over a dry creek bed to assess a potential landing site. The second pass was accomplished up-creek into rising terrain. The airplane was configured with full power and with flaps at 20°, and it was about 50 ft above ground level at 80 mph. The pilot reported that the airplane encountered a downdraft as it transitioned from overflying the trees to overflying the creek bed, which he attempted to correct, but the airplane aerodynamically stalled.

Following the stall, the pilot attempted to land on a dry creek bed. The airplane touched down on the creek bed, then bounced and descended into a "dry cut channel." The airplane came to rest nose down in a near vertical position. The airplane was destroyed by a postcrash fire.

According to the National Transportation Safety Board's Pilot Aircraft Accident Report, the pilot reported that the event could have been avoided by making the low pass along descending terrain at a higher airspeed.

The pilot reported that there were no preaccident mechanical malfunctions or failures with the airplane that would have precluded normal operation.

Text from the NTSB. Open the NTSB docket for GAA17CA473 for the full record.