Incident Summary
During a descent through flight level 250, the flight crew detected an unusual vibration. In response, they reduced speed, which led to a decrease in the vibration. Subsequently, a flight attendant reported that a portion of the right wing was missing. The aircraft continued to land without further incident.
Examination Findings
Post-flight inspection of the aircraft revealed that approximately 1.5 feet of the right aileron had separated in flight. The separated section was recovered and examined. The examination showed very little flow of the adhesive between the skin and the core of the aileron. This lack of adhesive flow was possibly due to the use of an adhesive that had exceeded its shelf life.
Maintenance History
The aileron had undergone a major repair in 1990, which involved replacement of the skin and core. It was then installed on the aircraft in 1992. No further work had been performed on the aileron after installation.