Event Description
During cruise flight, the empennage experienced flutter. The pilot immediately reduced engine power, and the flutter subsided after approximately three seconds.
Inspection Findings
An examination of the empennage disclosed that the bulkhead at fuselage station (FS) 256.9 exhibited cracks at the four corners of the assembly. Additionally, buckling of the fuselage skin was noted adjacent to the damaged bulkhead.
Ruddervator Balance Check
The ruddervators were removed from the airframe and balance checked in accordance with the Bonanza 35 Series Shop Manual. The left ruddervator exhibited a static underbalance moment of 23.73 inch-pounds (trailing edge heavy), and the right ruddervator exhibited a static underbalance moment of 22.95 inch-pounds. According to the service manual, the required static underbalance range is 16.80 to 19.80 inch-pounds. Both ruddervators had been reskinned (or replaced) and repainted. An unbroken paint seal around the screws that attached the counterweights to the ruddervators indicated that the counterweights had not been removed subsequent to repainting.