Special Conditions: Douglas Models DC-8-61, -61F, -63, -63F, -71, -71F, -72, -72F, -73, and -73F Airplanes; High Intensity Radiated Fields (HIRF)

These special conditions are issued for Douglas Models DC-8- 61, -61F, -63, -63F, -71, -71F, -72, -72F, -73, and -73F airplanes modified by ABX Air, Inc. These airplanes, as modified by ABX Air, Inc., will have novel and 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 the Innovative Solutions and Support (IS&S) Duplex Reduced Vertical Separation Minimum (RVSM) system which will allow for the removal of the existing altitude alerter, encoding altimeters, air data computer, and standby altimeter. 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 provided by the existing airworthiness standards.