Accident Details
On July 14, 2019, at approximately 1315 central daylight time, a Piper PA18-150, registration N6963B, was substantially damaged in an accident near Osceola, Wisconsin. The commercial pilot was not injured. The flight was conducted under 14 Code of Federal Regulations Part 91 as a glider towing operation.
Pilot Report
The pilot reported completing three uneventful glider tows prior to the accident flight. During the fourth tow, the pilot applied full power for takeoff and became airborne at 55 mph indicated airspeed. At an altitude of about 5 to 15 feet above the ground, the pilot heard a sudden "bang." The nose of the airplane pitched up approximately 40 degrees and rolled right about 45 degrees. The aircraft seemed uncontrollable with rudder inputs. The pilot managed to level the wings before the airplane struck the ground hard. The pilot then reduced power to idle and applied brakes. The airplane skidded between two electric poles, bounced onto a road, traversed a ditch, and came to rest inverted. The empennage sustained substantial damage. The glider being towed released the tow rope and landed uneventfully nearby.
Examination Findings
Post-accident examination of the airplane revealed a broken attachment fitting on the right horizontal stabilizer. The Ceconite fabric covering was removed from both the right and left stabilizers for inspection. The attachment corner of the right stabilizer frame was fractured. Pitting, multiple broken welds, and corrosion were observed around the fracture site. Additionally, the right stabilizer frame had been fabricated and was not an Federal Aviation Administration/parts manufacturer approval (PMA)-approved part.
Maintenance History
Review of maintenance records indicated that the stabilizer assembly had been removed for inspection, refurbished, and replaced multiple times. The most recent maintenance was performed on March 1, 2019, during which an annual inspection was completed and new sleeves for the forward attachment points were fabricated and installed on the stabilizer assembly.