Special Conditions: Raytheon Model HS.125 Airplanes; High-Intensity Radiated Fields (HIRF)

These special conditions are issued for a Raytheon Model HS.125 airplane modified by LJSC Ltd. This modified airplane will have a novel or unusual design feature when compared to the state of technology envisioned in the airworthiness standards for transport category airplanes. The modification incorporates the installation of two Air Data Display Units and two Air Data Sensors manufactured by Innovative Solutions and Support. These systems perform critical functions. 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.