Special Conditions: McDonnell Douglas Model DC-8-71/-73/-73F Series Airplanes; High-Intensity Radiated Fields (HIRF)

These special conditions are issued for McDonnell Douglas Model DC-8-71/-73/-73F series airplanes modified by Hollingsead International, Inc. These modified airplanes will have novel or unusual design features when compared to the state of technology envisioned in the airworthiness standards for transport category airplanes. The modification incorporates the installation of new Liquid Crystal Flight Instruments, the Attitude Directional Indicator (ADI) and the Horizontal Situation Indicator (HSI). The liquid crystal flight instruments will utilize electrical and electronic systems that 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.