Vertical Stabilizer Spar Fracture on a Rental and Flight Training Airplane (N16319)

Incident Overview and Aircraft History The airplane returned from a local flight with substantial damage caused by a crack through its vertical stabilizer spar. Throughout its service life, the aircraft had been used as a rental and flight training airplane. The airplane and its vertical stabilizer had accumulated a total time of 13,810 hours. ## Maintenance and Inspection Findings Maintenance personnel reported that the crack was not present during the airplane’s last annual inspection, which was performed seven hours before the flight. The crack was located approximately six inches above the base of the vertical stabilizer and extended horizontally about one and one-half inches from the right side of the stabilizer into the three-and-one-half-inch spar. ## Structural Examination Maintenance personnel had previously installed a doubler at the root of the rudder as a preventative measure against skin cracks. Examination of the fracture surfaces was consistent with overstress fractures.