On February 26, 2001, at 1030 eastern standard time, a Cessna 500, N234UM, operated by an airline transport pilot, sustained substantial damage when during landing, the airplane departed the end of runway 32 (5,235 feet by 100 feet, ice-covered asphalt) at the Sault Ste Marie Municipal - Sanderson Airport (ANJ), Sault Ste Marie, Michigan, and subsequently encountered terrain. Visual meteorological conditions prevailed at the time of the accident. The medical "Lifeguard" flight was being conducted under the provisions of 14 CFR Part 91. An instrument flight rules flight plan was on file from the Willow Run Airport, Ypsilanti, Michigan, to Sault Ste Marie. The captain, first officer, and two medical technicians on board the airplane reported no injuries. The airplane departed Ypsilanti, Michigan, at 0935. In his written statement, the captain said that he flew the VOR approach to runway 32. At 2,500 feet, the captain said that they were out of the clouds and initiated a visual straight-in to the runway. "After aligning the airplane with the rwy (runway) it became obvious to me that there was some contamination on the rwy, maybe compacted snow or maybe ice with some fresh snow over it; therefore, I briefed a go-around by midfield if deceleration was inadequate." The captain said that they touched down within the first third of the runway. "...initially we experienced some deceleration but close to midfield the airplane fishtailed at which time I called for a speed reading." He said the first officer "read 80 knots. By then we had passed the midfield and I called a go-around." The captain said he heard the first officer remark that there was not sufficient runway remaining. "... it was some in excess of 1/3 remaining, but I carried on." In his written statement, the first officer said that about 2 miles out from the runway, "unicom called and said that braking was nill." The first officer said he discussed this with the captain and he said, "If we were not under control at halfway down the runway, we would go around". The second pilot said they touched down at a normal distance down the runway and he extended the airbrakes. "The Captain began braking. I had noted earlier that there was a taxiway midpoint on the runway. As we passed that point I felt we were committed to stay on the ground. At the same time it was becoming obvious [that] we were going off the end of the runway." The second pilot said the captain then asked, "What is our speed? I replied 80 kts (knots)!" The captain then added power and said, "we are going around." The first officer said that as he retracted the airbrakes he exclaimed, "There is not enough runway! I braced myself as the aircraft went into the snow." In his statement to a Federal Aviation Administration (FAA) inspector, the fixed base operator (FBO) briefer at Sault Ste Marie Airport said that he talked to the pilot on the radio before the pilot attempted to land. The FBO briefer told the pilot that the runway was ice-covered and that there was no braking action. The FAA inspector examined the airplane at the accident site. The airplane was found at the bottom of small cliff, approximately 300 feet northwest of the departure end of runway 32. The airplane's forward pressure bulkhead was bent aft. The airplane's left wing leading edge was bent inward, and the airplane's nose gear was broken aft. Flight control continuity was confirmed. An examination of the airplane's engines and other systems revealed no anomalies. A Notice to Airman, published February 15, 2001, and in effect at the time of the accident, stated for ANJ, "icy runway, nil braking."