On November 15, 2005, at 1530 central standard time, a Cessna T310R, operated by Airmax Airlines, received substantial damage during a hard landing on runway 31 (5,639 feet by 100 feet, asphalt) at Fergus Falls Municipal - Einar Mickelson Field (FFM), Fergus Falls, Minnesota. Visual meteorological conditions prevailed at the time of the accident. The 14 CFR Part 135 on-demand cargo flight was operating on an instrument flight rules flight plan. The commercial pilot was uninjured. The flight originated from Hector International, Fargo North Dakota, at 1445, and was en route to FFM. The pilot stated that he received a weather briefing about 1300 and he knew that the freezing levels were "low." He called dispatch and knew he was going to have "difficulty" flying out of FFM. He stated that the operator does not have a deicing program in place so he put the airplane in a hanger before he departed. After departure from FFM, he climbed to the filed cruise altitude of 5,000 feet mean sea level where the airplane began to accumulate ice. He waited for the ice on the wings to accumulated to 1 inch thickness and operated the boots three times prior to landing. The propeller deice, window hot plate, and pitot heat were on. He flew the full instrument approach and at the final approach fix was in visual conditions. When he used flaps, he experienced changes in airspeed while maintaining the glide slope. The power was set 20% higher than "normal." He stated that while reducing power to land, he experienced "unreported" wind shear that caused a hard unaligned landing. The right main landing gear collapsed and the airplane veered off the runway. According to the Federal Aviation Administration inspector, the airplane was certified for flight into icing conditions. On-scene inspection of the airplane revealed 1 1/2 - 2 inches of ice on the right wing and vertical and horizontal stabilizers. The left wing had a lesser thickness of ice than the right wing.