The airplane lost aileron control while practicing commercial pilot maneuvers, resulting in a collision with a tree during the subsequent emergency landing. The pilot stated that he moved the control wheel to the right, but the airplane did not respond. He looked at the wing as he continued moving the control wheel and realized that the ailerons were not operating. He landed the airplane on a dirt road using rudder and throttle to control movement. During the landing, the right wing impacted a tree. The design of the control wheel to control column interface utilizes a nut plate installed inside the column. A screw and collar are then inserted through the bottom of the control wheel and into the nut plate inside the column to secure it to the column. Various Federal Aviation Administration (FAA) and Society Automotive Engineers (SAE) publications note that for proper clamping action at least three threads should show above the nut. FAA publication AC 43.12 notes that screws and bolts should ideally be put in from the top down when at all possible to prevent the effects of gravity and vibration from loosening the fasteners. During an on scene examination of the airplane, the FAA inspector found the attaching screw and collar from the left control wheel on the floor. The inspector moved the left control wheel and found that the column would not move. He moved the column and verified aileron continuity. Post accident examination of the control wheel attachment screw, and several others from the same make and model airplane, revealed that there was a slight difference in length between them all. It was also noted that some had different letter markings on the screw head. On average, when the screws were fully torqued, between 1 and 1 1/2 threads were exposed beyond the top of the nut plate. The torque of the fastenings was checked on all 35 Pipers in the operators fleet, which consists of 19 PA-28-181's and 11 PA-44-180's. Ten control wheel screws were found to be loose. The screws turned 1/8 to 1/4 revolution before coming up to torque. A number of other flight schools were contacted, and all found loose screws that required a 1/8 to 1/4 revolution turn before coming up to torque.

The National Transportation Safety Board determines the probable cause(s) of this accident as follows:

Index for Jul2003 | Index of months