Event Description
An aircraft was observed entering a level, counter-clockwise turn approximately 200–300 feet above ground level. Witnesses reported that after about three-quarters of the turn, the right wing separated from the aircraft. Subsequently, the aircraft descended rapidly to the ground and was consumed by fire upon impact.
Airframe Record Examination
Review of the airframe records indicated that the aircraft's original struts were still installed, with a total of 4,945 hours of service. There was no indication of any significant maintenance performed on these components.
On-Site Examination
Examination at the accident site revealed that the right wing forward lift strut had separated completely at a point approximately eight inches above its inboard end, which corresponds to the right main landing gear attach point. The fracture surfaces showed evidence of pre-existing damage.
Metallurgical Examination
Metallurgical examination of the separated strut found that the lower inside surface at the separation location was corroded. Fatigue cracking had progressed from this corroded area through a portion of the top surface of the strut, leading to complete separation.