On November 3, 2002, about 1310 Alaska Standard Time, a Douglas DC-3 airplane, N32TN, sustained substantial damage when it struck an object while landing at a privately owned airstrip located at Port Alsworth, Alaska. The airplane was being operated as a visual flight rules (VFR) cargo flight under Title 14, CFR Part 135, when the accident occurred. The airplane was operated as Flight 1028 by TransNorthern, LLC., Anchorage, Alaska. The commercial certificated captain, airline transport certificated first officer, and one passenger, were not injured. Visual meteorological conditions prevailed, and company flight-following procedures were in effect. The flight originated at the Ted Stevens Anchorage International Airport, Anchorage, about 1205. During a telephone conversation with the National Transportation Safety Board investigator-in-charge on November 4, the operator's general manager reported that the airplane was being utilized to transport building materials to Port Alsworth. The general manager said that the crew told her that during a prelanding inspection of the Port Alsworth airstrip, both crew members noticed a large tractor that was parked alongside the approach end of the airstrip. She said that the crew planned to fly an approach that would avoid the tractor. She said as the approach phase of the landing continued, the crew encountered a slight downdraft as the airplane passed over the approach end of runway 05L. During the slight descent, just before touchdown, the airplane's left wing struck a 25-foot high iron mast that was attached to the parked tractor. After the collision, the crew was able to complete the landing. A postaccident inspection of the airplane revealed that 14 feet of the airplane's left wing was severed from the airplane during the collision. Additionally, the left elevator was damaged. The captain reported to the general manager that he, as well as the first officer, were unaware the 25-foot high iron mast was attached to the tractor.