NTSB Factual Report

On July 9, 2005, at 1050 central daylight time, a Cessna 210E, N4933U, was landed in a corn field in La Gygne, Kansas, following a loss of engine power. The private pilot and two passengers were not injured. The airplane was substantially damaged. The 14 Code of Federal Regulations Part 91 personal flight was operating in visual meteorological conditions without a flight plan. The flight originated from Gardner, Kansas, at 1030, with an intended destination of Ozark, Missouri.

The pilot reported that upon reaching 7,500 feet he was adjusting the engine to cruise power, when the engine went to idle. He reported he pulled the throttle out, pushed it back in and got a "little power surge." He stated that there was no change in power when he adjusted the throttle a second time. The pilot reported, "I attempted a third time and it came out of the dash (about a foot)." He reported he threaded the cable back into the instrument panel and established communications with air traffic control inflight watch.

The pilot stated he was given a vector to the Miami County Airport and upon reaching an altitude of 3,000 to 3,500 feet, he realized the airport was too far away and that he needed to pick a field in which to land. The pilot stated he selected a corn field and made a "textbook" landing, but the airplane "weathervaned" shortly after touching down. The pilot stated, "I informed them [air traffic control] that the airplane looked to be in pretty good shape, not realizing the amount of damage that corn can do to sheet metal!"

The throttle cable was removed from the airplane and sent to the National Transportation Safety Board's Materials Laboratory in Washington D.C. for examination. The factual report of this examination stated that the motion of the throttle knob is transmitted to the steel plunger through the cable, which is composed of a strand of seven steel wires surrounded by a coiled steel inner spring. When in operation, both the stranded cable and the inner spring move within an outer coiled steel flat wire casing. The seven wires and the inner spring fractured where they were connected to the end of the plunger. The wiires on one side of the strand (on both sides of the fracture) showed wear from relative motion between the stranded cable and the inner spring. The inner spring itself showed matching areas of wear.

The report continued to state that areas of fatigue cracking were visible on both the cable and the inner spring. In addition, the report stated the area of wear visible on the outer sleeve of the plunger began to impinge on the inner brass tube. The brass tube was the part affixed to the carburetor body, and actuation of the throttle would slide the central part of the plunger within the brass tube while sliding the outer sleeve around the outside of the brass tube. The outer sleeve of the plunger acts as a cover primarily to keep water out of the mechanism. The outer sleeve of the plunger was locally worn, and the wear penetrated through the outer sleeve of the plunger and partially into the brass tube... . No objects were found which would have rubbed against the plunger resulting in the wear.

NTSB Probable Cause

The failure of the throttle control cable which resulted from wear followed by fatigue cracking. A factor associated with the accident was the corn crop which the airplane contacted during the forced landing.