Special Conditions: Avcon Industries, Inc.; Learjet Model 23 Series Airplanes; High-Intensity Radiated Fields (HIRF)

These special conditions are issued to Avcon Industries, Inc., for the Learjet Model 23 series airplanes modified by Avcon Industries, Inc. This airplane as modified by Avcon Industries, Inc., will have a novel or unusual design feature associated with the installation of a new Reduced Vertical Separation Minimum (RVSM) air data system. The applicable airworthiness regulations do not contain adequate or appropriate safety standards for the protection of these systems from the effects of high-intensity radiated fields (HIRF). These special conditions contain the additional safety standards that the Administrator considers necessary to establish a level of safety equivalent to that established by the existing airworthiness standards.