Incident Overview
During cruise flight, the flight crew experienced a pronounced airframe vibration. Simultaneously, the number two engine thrust reverser armed light illuminated; no other warning lights activated. The crew initiated the abnormal procedures checklist, retarded the number two throttle to idle, and reduced airspeed. A precautionary landing was performed at the departure airport.
Post-Flight Examination
Following the landing, company maintenance personnel examined the aircraft. The inspection disclosed that the right wing fixed trailing edge panel had separated from the wing structure. The detached panel subsequently collided with the fore flap and the inboard mid flap on the same wing.
Operational Sequence
The crew's actions, including throttle reduction and speed reduction, were consistent with standard abnormal procedures for a vibration event. The flight returned to its point of origin without further incident. The specific cause of the panel separation was not determined during the on-site examination.