On June 16, 2001, at 1040 central daylight time, a Cessna 172S, N494SP, operated by a private pilot, sustained substantial damage when it overran runway 14 (4,100 feet by 60 feet, dry concrete) and nosed over during an emergency landing at the Cambridge Municipal Airport, Cambridge, Nebraska. Prior to the accident, the pilot reported that the airplane's engine was running rough while in cruise flight. Visual meteorological conditions prevailed at the time of the accident. The personal flight was being conducted on a visual flight rules plan under the provisions of 14 CFR Part 91. The pilot and passenger on board reported no injuries. The cross-country flight originated at Plattsmouth, Nebraska, at 0821, and was en route to the United States Air Force Academy, Colorado. In his written statement, the pilot said that he was approximately 20 miles south of Cambridge, Nebraska, at 6,500 feet mean sea level when the airplane's engine began to run rough and the airplane began to lose altitude. The pilot said he immediately turned toward the airport and declared an emergency. "I had partial power and was able to hold a slow descent. I was not sure that I was going to make the airport but in time I spotted the airport and determined I was quite high." The pilot said he tried the common traffic advisory frequency for the airport to obtain runway and wind information but got no response. The pilot said he made an assumption that the winds were 5 to 10 knots out of the southwest and determined he would make a downwind landing on runway 32. "I approached the airport high and made a right 360 [degree turn] to lose altitude, but still came out too high for an approach. I considered making another 360 but I was concerned that [the] engine might quit while I was over the town." The pilot said that his best option now was to land on runway 14. He said that after he turned on to final, he realized that he was on a downwind approach, but decided that he had no option but to continue. "I had the throttle out to idle well before the threshold but I was being pushed by a fairly strong wind from (in retrospect) about 300 degrees. I had great difficulty getting the plane on the runway and bounced a couple of times. The pilot said it became apparent to him that he was not going to stop on the runway. "I decided to try to divert to [a] plowed field to the left of the runway ... I used the throttle to boost the plane over a road and a fence. Once clear I chopped the power and stalled the plane into the field. I estimated that the airspeed was about 35 kts (knots) and the plane was in a full stall. Very soon after touchdown, the plane, quite slowly, turned over on its nose." A witness on the airport said that he saw the airplane attempt to land on runway 14. When the airplane was overhead, the witness said he saw the airplane trailing white smoke. The witness said that the airplane was high at the approach end of the runway. He estimated that the airplane touched down once, approximately 1/3 of the way down the runway. He said that the airplane was "way too fast, too much speed." The witness estimated the winds were gusting 10 to 15 knots out of the north-northwest. A Federal Aviation Administration inspector examined the airplane at the accident scene. The airplane was resting inverted in the center of a plowed field approximately 400 feet from the departure end of the runway. The airplane's nose gear was collapsed. The cowling and forward fuselage were crushed upward and aft. The engine, engine mounts, and firewall were bent downward. Oil was observed along the bottom of the airplane beginning at the engine and running aft to the tail. The airplane's left wing was bent downward at the wing root. The left wing strut was bent upward at mid-span. The right wing tip was bent inward. The vertical stabilizer and rudder were crushed downward. One of the airplane's propeller blades was bent aft at mid-span approximately 10 degrees. Flight control continuity was confirmed. An examination of the airplane's engine showed the intake and exhaust valves push rod tubes pushed upward and off on the number 2 cylinder. The intake valve push rod was bent upward. The exhaust valve push rod was broken 5 inches outward from the tappet seat. An examination of the airplane's other systems revealed no anomalies.