On June 12, 2012, at 2034 mountain daylight time, a Cessna A185F, CG-ZVF, registered to Transwest Air Limited Partnership and operated by the pilot, sustained substantial damage during a landing after a loss of engine power near Winnett, Montana. The commercial pilot, the sole occupant, was not injured. The pilot was operating the airplane under the provisions of 14 Code of Federal Regulations Part 91. The flight departed from High River Regional Airport, High River, Alberta, Canada, and was destined for Billings Logan International Airport, Billings, Montana. Night visual meteorological conditions prevailed and no flight plan was filed. The pilot was interviewed following the accident. He reported that he had recently lost his wife and had not been thinking correctly. He indicated that he likely would not have made the flight under normal circumstances. The pilot did not hold a current medical or flight review. He purchased the stored airplane in Canada and did not file a required flight plan upon his departure. Before takeoff, the fuel tanks were filled to capacity and the pilot drained fuel samples from all of the fuel tanks. He did not identify water or other contaminants. While in cruise flight over a highway, the pilot switched fuel tanks and the engine sputtered and then lost power. As the airplane descended, the pilot tried to restart the engine. The airplane continued to descend and the pilot did not see a transmission line until the last minute due to the dark lighting conditions. He switched back to the original tank, attempted to restart the engine again, and it restarted. After the airplane impacted the transmission line, the pilot was able to maneuver the airplane and then landed it on a highway. The pilot attributed the engine sputtering to undetected water in the fuel system. Later operation of the engine and fuel system showed no mechanical anomalies. According to the Federal Aviation Administration (FAA) accident coordinator, the right wing impacted a transmission line during the landing, resulting in substantial damage. Post accident fuel sampling identified no fuel contaminants. A flight plan or flight itinerary is required in Canada when pilots are more than 25 nautical miles from the departure airport or when operating between Canada and a foreign country.