NATA supported a broader Joint Aviation Community filing to the FCC that frames the operational and safety stakes for our members as FCC considers opening additional Upper C-Band spectrum for expanded terrestrial wireless use. Aviation groups warn the move could materially change the adjacent-band environment next to the 4.2 to 4.4 GHz radio altimeter band and increase interference risk for radio altimeters, which are safety-critical for low-visibility approaches and other low-altitude operations. The comments from the Joint Aviation Community emphasize that the FCC and FAA must coordinate and align their rulemakings, so operators are not caught between conflicting requirements, while protecting radio altimeters as a safety-critical sensor for low-altitude operations and other onboard systems.
For members, the comments underscore significant cost exposure and the likelihood of a multi-year retrofit or replacement effort. That is, FAA estimates total compliance costs around $4.49B, while stakeholders estimate costs could exceed $7B, driven primarily by the anticipated cost of new radio altimeter systems, along with installation, certification, downtime, and maintenance capacity constraints.
In parallel, NATA and NBAA jointly called on the FCC to apply its established emerging technologies framework to Part 91 and Part 135 operators as it considers expansion of Upper C-Band wireless services. In comments filed Feb. 18, NATA and NBAA emphasized that any required modification or replacement of altimeter equipment—driven by commission-initiated spectrum changes—must include equitable reimbursement of reasonable costs, consistent with the precedent set during the Lower C-Band transition. The FCC’s proposal could affect thousands of aircraft ahead of a planned 2027 spectrum auction.