The airline transport certificated pilot was landing at a remote mining airstrip during a public use flight under Title 14, CFR Part 91. The airstrip slopes uphill, and is about 1,000 feet long, and about 16 feet wide. The pilot indicated that during the landing roll, the right main landing gear tire dropped into a rut, pulling the airplane to the right, into several willow trees. During an inspection of the airplane at a Department of Interior repair facility, inspectors discovered damage to an inboard stabilizer rib, which required a major repair. The accident airstrip was examined by an air safety investigator with the Department of the Interior, Aviation Management Directorate, Aviation Safety Division. The investigator reported that the airplane's tailwheel contacted the ground about 53 feet before the beginning of the airstrip. The main landing gear tires contacted the airstrip surface about 75 feet after the initial tailwheel strike. The propeller struck the ground about 52 feet beyond the approach end of the airstrip, and about 30 feet from the initial contact with the main wheels. Following the propeller strikes, the airplane veered to the right and ran through several 2 to 4 foot tall willow trees.

The National Transportation Safety Board determines the probable cause(s) of this accident as follows:

The pilot's misjudged distance/altitude during the landing touchdown and subsequent undershoot, and his failure to maintain directional control of the airplane during the landing roll, which resulted in an on-ground encounter with high vegetation.