improperly balanced ruddervators and improperly installed ruddervator (elevator) trim tabs, due to improper maintenance, which resulted in ruddervator flutter and substantial damage in the area of the aft fuselage. Factors relating to the accident were: improper planning/decision by the owner/operator (pilot) by failing to ensure that the annual inspection and required aircraft maintenance were performed; and turbulence that led to vibration of the improperly balanced ruddervator.