What happened
A commercial pilot was performing what was intended to be his final flight in the aircraft before transitioning to a position as a commuter pilot. Prior to departure, a Certified Flight Instructor (CFI) spoke with the pilot, who stated his intention to "roll the airplane." During the maneuver, witnesses observed the right wing folding backward accompanied by a loud, booming noise. There were no reports of smoke or fire during the in-flight event.
The investigation
An examination of the wreckage provided details regarding the structural failures. The left stabilator failed due to positive overload, specifically failing in a downward direction. Regarding the wings, the right wing failed at both the wing root and outboard of the right engine, while the left wing failed outboard of the left engine.
An inspection of the wing spar revealed evidence of upward (positive) bending; however, the actual failure occurred in the downward direction. All examined fracture surfaces showed evidence of overload, with no evidence of fatigue found during the investigation.