Incident Overview
Approximately five minutes after takeoff, while cruising at 6,500 feet at 160 to 165 knots, the 1947 model airplane encountered turbulence and experienced an airframe vibration. In response, the pilot reduced airspeed, which eliminated the vibration. The pilot then landed the airplane without further incident.
Examination Findings
A subsequent examination of the airplane revealed that the fuselage station 256.9 bulkhead, located directly below the leading edge of the V-tail, was cracked at all four corners. The crack was observed during the post-flight inspection.
Ruddervator History
Further investigation disclosed that the airplane's ruddervators had been removed in 1995 for reskinning due to corrosion. The reskinning was accomplished using Beech factory replacement skins. Following the reskinning, the ruddervators were painted with several layers of paint. This additional paint necessitated the installation of an extra one-pound lead weight on the outboard tip of each ruddervator to achieve correct control surface balance.
Pilot's Observation
The pilot stated that he could not be sure whether the station 256.9 bulkhead was damaged in flight or when the ruddervator contacted a hangar support beam as the airplane was being pushed into a hangar. The source of the damage remains uncertain based on the available information.