The accident happened during the Piper PA-12’s first flight in Anchorage, Alaska, after undergoing maintenance and modification over the course of several years.
A witness reported that, during the takeoff, the plane climbed steeply in an extreme, nose-high attitude until it “pivoted” at the apex of the climb and then entered a descent straight to the ground.
The described motions are consistent with the airplane exceeding its critical angle of attack and entering an aerodynamic stall. Crush damage to the nose of the airplane and the leading edges of the wings was consistent with a nearly vertical flight path at the time of impact.
Examination of the wreckage revealed that the elevator control cables were misrigged. They were attached to the incorrect (opposite) locations on the upper and lower elevator control horn, resulting in a reversal of elevator control inputs.
Maintenance logs for the airplane contained no entries more recent than 2007. Several people reported that the pilot often performed maintenance on the airplane, however no one knew who performed maintenance on the elevator controls.
A “BEFORE TAKEOFF” checklist for the airplane included the ite, “CONTROLS – FREE AND CORRECT.” If the pilot had checked the elevator for correct motion before takeoff, he likely would have discovered that it was misrigged.
The NTSB determined the probable cause as the incorrect (reverse) rigging of the elevator control cables, and the pilot’s inadequate preflight inspection, which failed to detect the misrigging.
NTSB Identification: ANC14FA050
This July 2014 accident report is provided by the National Transportation Safety Board. Published as an educational tool, it is intended to help pilots learn from the misfortunes of others.
