The commercial pilot was conducting a 14 CFR Part 91 public use flight, and was landing the tundra tire-equipped, tailwheel airplane on an off-airport landing site in support of federal law enforcement activities. The pilot said he landed on an unimproved strip of tundra, and during the landing roll the right main wheel hit an unseen ledge, and then a hole, and nosed down. According to the pilot, there were no known mechanical anomalies with the airplane prior to the accident. The operator said the airplane sustained a broken engine mount, and structural damage to the forward fuselage and firewall.

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

The pilot's selection of unsuitable terrain for landing, which resulted in the airplane nosing down during the landing roll. A factor associated with the accident was the rough and uneven terrain.