January 15, 1998
The purpose of this Special Airworthiness Information Bulletin (SAIB) is to advise operators of the importance of ruddervator balancing on Raytheon (Beech) Model 35 Series airplanes ruddervator balancing.
There have been several incidents involving accidents due to flutter of an unbalanced ruddervator on Raytheon Model 35 Series airplanes. Fortunately, in each case, the pilots was were able to recover from the flutter condition by reducing power. and landing without further incident. The proper and accurate balancing of control surfaces is essential to the safe operation of aircraft. This is also the subject of Airworthiness Directive (AD) 94-20-04, applicable to the Model 35 Series airplanes.
In this SAIB, the FAA is recommending, but not requiring that ruddervators must be balanced off the airplane whenever they are repaired or repainted (even if only stripes are added). They ruddervators should must be balanced using the criteria and instructions in accordance with Bonanza Maintenance Manual Number 35-590073. In addition, all operators are urged to review the applicability and requirements of See AD Airworthiness Directive94-20-04 for additional information to insure complete compliance with the specified requirements of that AD.
For Further Information Contact
Steven Litke Larry Engler, Aerospace Engineer, Federal Aviation Administration, Wichita Aircraft Certification Office, 1801 Airport Road, Room 100, Wichita, KS 67209, (316) 946-41274122.