Special Conditions: Gulfstream Aerospace Corporation Model G-1159 Gulfstream II Airplanes; High Intensity Radiated Fields (HIRF)

These special conditions are issued for the Gulfstream Aerospace Corporation Model G-1159 Gulfstream II airplanes modified by Gulfstream Aerospace Corporation, Dallas, Texas. These modified airplanes 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 dual electronic attitude direction indicators (ADI) and dual horizontal situation indicators (HSI). 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 the Administrator considers necessary to establish a level of safety equivalent to that provided by the existing airworthiness standards.