2.4.1 Cable Routing ConsiderationsWhen routing antenna cables, observe the following precautions:• All cable routing should be kept as short and as direct as possible• Avoid sharp bends• Avoid routing cables near power sources (e.g., 400 Hz generators, trim motors, etc.) or near powerfor fluorescent lighting• Avoid routing antenna cables near ADF antenna cable (allow at least a 12-inch separation)2.5 Installation Approval Considerations for Pressurized AircraftAntenna and cable installations on pressurized cabin aircraft require FAA approved installation design andengineering substantiation data whenever such installations incorporate alteration (penetration) of thecabin pressure vessel by connector holes and/or mounting arrangements. Use of existing bulkheadconnectors previously approved by other means is permissible without additional approval.For needed engineering support pertaining to the design and approval of such pressurized aircraft antennainstallations, it is recommended that the installer proceed according to any of the following listed options:1. Obtain approved antenna installation design data from the aircraft manufacturer.2. Obtain an FAA approved Supplemental Type Certificate (STC) pertaining to and valid for thesubject antenna installation.3. Contact the FAA Aircraft Certification Office in the appropriate Region and requestidentification of FAA Designated Engineering Representatives (DERs) who are authorized to pre-