Primary finding
Probable cause
improper use of carburetor heat. Factors related to the accident were carburetor icing conditions, and the sign and fence poles.
Investigator assessment
Analysis narrative
The pilot reported a loss of engine power during the cross country flight. He was given information regarding a near-by airport but was unable to reach the airport and a forced landing was made on a road. The airplane contacted sign posts, fence posts, and a ditch during the landing. Post accident inspection failed to reveal any mechanical failure/malfunction. The pilot reported to ATC that he was encountering ice pellets and picking up rime ice during the flight. The temperature/dewpoint were 35 degrees f. And 21 degrees f. Respectively at the time of the accident. Icing probability charts indicate these conditions were conducive for light to moderate carburetor ice at glide and cruise power.
Source record
Factual narrative
On March 10, 1994, at 1350 central standard time, a Mooney M20C, N6811N, registered to Michael Geyer and flown by a private- instrument rated pilot collided with sign posts, fence posts, and a ditch during a forced landing in Richland Center, Wisconsin, while on a CFR 14 Part 91 business flight. Visual meteorological conditions prevailed and an IFR flight plan was filed. The airplane was substantially damaged. The pilot and passenger were not injured. The flight originated from Milwaukee, Wisconsin, on March 10, 1994, at 1237 cst. The pilot stated that while en route to St. Paul, Minnesota, just after passing the Lone Rock VOR, a "very sudden, immediate loss of engine power" was experienced. He stated that best glide speed was established, and emergency restart procedures were followed to no avail. Information regarding the nearest airport was requested from the Chicago Air Route Traffic Control Center. The pilot was informed that Richland Center Airport was the closest airport. The pilot stated he headed toward the airport, but realized they could not make it there so he selected a road on which to land. According to the pilot, each wing struck a sign post during the landing and the left wing contacted several metal fence posts. The airplane then veered to the left and came to rest in a ditch. Post accident inspection of the airplane and engine was conducted by an inspector from the Milwaukee Flight Standards District Office. The inspector reported no deficiencies were found which would have resulted in the loss of power as described. The temperature and dewpoint reported at Madison, Wisconsin, at 1251 cst were 35 degrees F., and 21 degrees F. respectively. According to icing probability charts, these conditions were favorable for light to moderate carburetor ice at glide or cruise power. The pilot reported to Milwaukee Departure Control during the flight that he was encountering ice pellets and was picking up light rime ice. -