In 2006, the FAA proposed requiring that many communications users seek FAA No Hazard Determinations not only before they make changes in the height of a tower, but also prior to frequency or power changes. The FAA sought to review applications to determine if proposals would create any interference to frequencies used by the by aircraft and by the FAA for air navigation purposes. This review would be in addition to any review that the FCC made of interference considerations. Many communications companies and engineering firms argued that this second layer of frequency review was unnecessary; and certain engineering groups contended that the FAA’s interference programs were not accurate – finding interference where none existed. After over 4 years of consideration,the FAA has now decided that most of the frequency blocks that it was considering did not really pose a threat to air navigation, with one exception. The FAA determined that interference problems do arise from FM operations, and thus the FAA did not dismiss their proposal to require its approval of FM changes – even where no tower height changes are planned.
The FAA, however, apparently will not be making this decision alone. Instead, that FAA is coordinating with the FCC and NTIA (an Administration in the Commerce Department that coordinates between various government agencies that use spectrum) to adopt policies that will govern the potential for interference from FM stations to FAA operations. The FAA’s Notice says that more information about what is to be proposed for FM stations should be forthcoming soon. This can be a real issue for FM stations, especially ones proposing significant power increases or frequency changes in congested metropolitan areas with numerous public, private and military airfields in the vicinity.