On November 3, 1994, at 1500 eastern standard time, a Cessna 185, N6688H, went off the right side of runway 24 during an attempted landing at Elizabethton Municipal Airport, Elizabethton, Tennessee. The instructional flight operated under 14 CFR Part 91, with no flight plan filed. Visual weather conditions prevailed at the time of the accident. The airplane sustained substantial damage, and the instructor pilot and three other pilots were not injured. The flight departed Elizabethton at 1300 hours. According to the certified flight instructor, he and three other private pilots were conducting routine training when he lost control of the airplane during a landing attempt. The airplane had rolled 500 feet when the left pedal collapsed. The airplane veered off the right side of runway and collided with the ground. A preliminary examination of the airplane disclosed that the instructor's left pedal unlocked and collapsed. Examination of the rudder pedal assembly failed to disclose any failed components. The examination disclosed some deformation to the locking assembly. The steering and braking systems operated normally, after the pedal assembly was restored to the normal operational position. The company maintenance inspector concluded that heavy braking caused the locking components to flex enough to collapse the left pedal assembly. The company maintenance inspector stated that rudder pedal malfunctions experienced by mission pilots were corrected by disabling the stow feature.