FTW02LA252

The CFI demonstrated a power-off stall to the student, and when he applied full power during the recovery, the throttle stuck between 1800-1900 rpm. The CFI verified that the friction lock was unlocked and attempted to push the throttle forward with both hands; however, the throttle would not advance forward. The pilot elected not to move the throttle back toward idle. The airplane was unable to maintain altitude, and a forced landing was initiated to a golf course. The CFI stated that he moved the throttle to idle on short final, and the throttle moved aft smoothly. The airplane touched down and during the landing roll the left landing gear contacted a sand trap, the airplane pivoted 90 degrees, and came to rest upright. Post-accident examination of the airplane revealed that the throttle cable's retaining bolt, nut, washer, and cotter pin were in place on the throttle lever arm of the carburetor, and the cable was secure in the mounting brace attached to the engine. The throttle cable was bent (approximately 75 degrees) into the engine truss, as a result of the impact. The throttle cable was moved from the full forward position (the position it was in when personnel arrived at the site) to the idle position; however, it was not possible to move the throttle. The airplane was moved from the accident site and second examination took place. During this examination it was determined that the cable installation at the throttle quadrant and carburetor were found to be proper. The throttle control was moved and the cable was observed to move, up to the point of the 75-degree bend. The cable was straightened and normal travel of the throttle cable was attained, although some binding was noted near the idle position. The throttle cable was then disassembled at the throttle control attach point, and the cable was removed. The inner cable was then removed from its outer sheathing. The inner cable winding was "somewhat bulged or unwound" at the upper end just forward of the throttle lever attach point. The cable sheath displayed a "shined spot" at a location corresponding to the unwound area. No other anomalies were noted. The reason for the binding was not determined.

On September 7, 2002, at 0945 central daylight time, a Piper PA-28-140 single-engine airplane, N686FL, was substantially damaged during a forced landing following a malfunction of the throttle control cable near Bella Vista, Arkansas. The airplane was registered to Precision Aircraft Maintenance, Inc., of Bentonville, Arkansas, and operated by Hughes Aviation of Bentonville. The flight instructor (CFI) and student pilot sustained minor injuries. Visual meteorological conditions prevailed, and a flight plan was not filed for the 14 Code of Federal Regulations Part 91 instructional flight. The local flight originated from Bentonville Municipal Airport, Bentonville, at 0900.

According to the CFI, he demonstrated a power-off stall to the student, and when he applied full power during the recovery, the throttle stuck between 1800-1900rpm. The CFI verified that the friction lock was unlocked and attempted to push the throttle forward with both hands; however, the throttle would not advance forward. The pilot elected not to move the throttle back toward idle. The airplane was unable to maintain altitude, and a forced landing was initiated to a golf course. The CFI stated that he moved the throttle to idle on short final, and the throttle moved aft smoothly. The airplane touched down and during the landing roll the left landing gear contacted a sand trap, the airplane pivoted 90 degrees, and came to rest upright.

An FAA inspector, who responded to the accident site, reported that the propeller was damaged, the nose landing gear was folded aft, and the left main landing gear was separated. The engine firewall was damaged, and the left main wing spar was cracked.

A representative from Hughes Aviation examined the airplane at the accident site. He observed that the throttle cable's retaining bolt, nut, washer, and cotter pin were in place on the throttle lever arm of the carburetor, and the cable was secure in the mounting brace attached to the engine. He noted that the cable was bent (approximately 75 degrees) into the engine truss, as a result of the impact. He stated that he attempted to move the throttle from the full forward position (the position it was in when he arrived at the site) to the idle position; however, he was unable to move the throttle. The airplane was moved to Bentonville Municipal Airport for further examination.

The airplane was examined at the Bentonville Municipal Airport by two FAA inspectors and a representative from Hughes Aviation. The cable installation at the throttle quadrant and carburetor were found to be proper. The throttle control was moved and the cable was observed to move up the 75-degree bend. The cable was straightened and normal travel of the throttle cable was attained, although some binding was noted near the idle position. The throttle cable was then disassembled at the throttle control attach point, and the cable was removed. The inner cable was then removed from its outer sheathing. The inner cable winding was "somewhat bulged or unwound" at the upper end just forward of the throttle lever attach point. The cable sheath displayed a "shined spot" at a location corresponding to the unwound area. No other anomalies were noted.

According to the aircraft's maintenance logbooks, the engine was installed on August 29, 2002, 2.25 hours prior to the accident. The last annual inspection occurred 1.02 hours prior the accident, and no anomalies were noted during the inspection.