On September 2, 2006, about 1245 Alaska daylight time, a wheel-equipped de Havilland DHC-3 airplane, N3125N, sustained substantial damage when it departed the runway and collided with a ditch during the landing roll at the Wainwright Airport, Wainwright, Alaska. The airplane was being operated as a visual flight rules (VFR) cross-country non-scheduled cargo flight under Title 14, CFR Part 135, when the accident occurred. The airplane was operated by Alaska Air Taxi, LLC., Anchorage, Alaska. The airline transport certificated pilot, the sole occupant, was not injured. Visual meteorological conditions prevailed, and a VFR flight plan was filed. The flight originated at the Wiley Post/Will Rogers Memorial Airport, Barrow, Alaska, about 1200. During a telephone conversation with the National Transportation Safety Board (NTSB) investigator-in-charge (IIC), on September 2, the pilot reported that he was landing on runway 23 at Wainwright. The gravel surface runway is 4,494 feet long, and 90 feet wide. The pilot said that during the landing roll, the airplane suddenly veered to the left. He applied right brake and right rudder, but the airplane departed off the left side of the runway, rolled down an embankment, and collided with a ditch. The left main landing gear assembly was fractured and displaced aft, against the fuselage. The propeller, engine, and the left wingtip struck the ground. On September 20, the chief pilot for the operator reported that after delays in getting recovery equipment to Wainwright, the airplane was recovered and disassembled for removal to Anchorage. The chief pilot indicated that the left aileron received structural damage, and the fuselage firewall had buckling and structural damage. In the Pilot/Operator Aircraft Accident Report (NTSB Form 6120.1) submitted by the pilot, the pilot indicated that the wind at the airport was from 180 degrees. He described the wind strength as 10 knots or greater, indicated by streaks of white foam on many nearby lakes, with the streaks of foam appearing perpendicular to the runway. In the Recommendation '(How could this accident have been prevented?)' portion of the NTSB accident report, the pilot stated: "I should not have landed at Wainwright that day with that crosswind condition. Having significant experience in that aircraft and over 1,200 hours in tailwheel aircraft, I felt that I could handle the crosswind situation."