SUPPLEMENTARY INFORMATION:

This is a summary of the Commission's ( printed page 66131) document ( Public Notice), in GN Docket No. 25-59, DA 26-1076, released on October 5, 2026. The Public Notice includes the following appendix: Appendix A, Proposed Radio Altimeter Rebate Categories and Amounts. The complete text of this document, including the appendix, is available on the Commission's website at docs.fcc.gov/​public/​attachments/​DA-26-1076A1.pdf, or by using the search function for GN Docket No. 25-59 on the Commission's ECFS web page at www.fcc.gov/​ecfs.

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Synopsis

With this Public Notice, the Wireless Telecommunications Bureau (Bureau) invites interested parties to comment on proposed categories, dollar amounts, and any other relevant information or procedures in connection with rebates to support retrofits of radio altimeters mandated by the Federal Aviation Administration (FAA) to facilitate the introduction of terrestrial wireless services in the Upper C-band. The adjacent 4.2-4.4 GHz band is allocated for the operation of radio altimeters, which are aeronautical safety systems primarily used at altitudes less than 2,500 feet above ground level to measure aircraft height above terrain and obstacles in all phases of flight. In adopting the Upper C-band R&O,91 FR 48700, July 31, 2026, the Commission worked in close coordination with a parallel FAA rulemaking to ensure a successful coexistence environment between new wireless operations and neighboring radio altimeters by increasing radio altimeters' robustness and signal rejection capabilities through retrofits. To ensure that new Upper C-band licensees may deploy on a predictable timeline aligned with the FAA's radio altimeter retrofit schedule, the Upper C-band R&O established that new 3.7 GHz Service licensees will, as a condition of their licenses, fund rebates to facilitate compliance with the FAA's retrofit requirements by defined classes of eligible aircraft owners and operators.

In deciding to facilitate compliance with the FAA's requirements in this manner, the Commission specifically noted that the radio altimeters subject to the retrofit are in the adjacent band, that they are not being relocated, and that their Commission authorizations are not being modified, putting them in a distinct posture as compared with in-band incumbents. Accordingly, and considering the large scope of potential claims for rebates with accompanying administrative burdens and operational costs, the Commission declined to adopt an actual cost reimbursement framework, finding it neither appropriate nor practicable in this context. Instead, the Commission adopted a rebate structure that will establish set amounts for different categories of aircraft based on the number of radio altimeters involved in each upgrade, the general level of efforts involved in each type of retrofit, and other reasonable and necessary factors involved in accomplishing each category of retrofit, including timing considerations such as the relevant FAA deadline for compliance. The Commission explained that this rebate structure was intended to streamline the overall process to make support for the retrofits available more quickly and to prevent fraud, waste, and abuse. The rebate structure is also meant to minimize the operational costs of administering the rebates and help to ensure that these adjacent band stakeholders are able to meet the applicable retrofit deadlines imposed by the FAA. With these same factors in mind, the Commission also specified defined classes of eligible aircraft, as well as aircraft owners and operators, who must be subject to the FAA deadlines and operate in the airspace of the contiguous United States in order to qualify for the rebates. The Commission also determined that it would not be in the public interest to offer rebates to foreign-registered aircraft operators and owners given the fluid and itinerant nature of their operations in the airspace of the contiguous United States, and determined that other entities and radio altimeter equipment would not be eligible for rebates. The Commission delegated authority to the Bureau to implement the rebate structure adopted in the Upper C-band R&O.

While the record to date reflects limited economic information relating to upgraded radio altimeters, we recognize that commenters and FAA have developed estimates in part based on experience with existing radio altimeter models. Based on these estimates, as well as more refined technical assistance provided by FAA subsequent to the completion of the FAA Final Rule, Appendix A hereto proposes draft categories and rebate amounts upon the type of aircraft, the number of radio altimeters each aircraft type has, and the relative level of effort involved in retrofitting such aircraft. Each aircraft category and corresponding rebate amount is predicated on certain assumptions, namely that the effort needed to upgrade an existing radio altimeter design will be less time- and resource-intensive than the acquisition and installation of an entirely new design. These draft rebate amounts also anticipate different timing and scheduling considerations for those entities that must comply with the FAA's first retrofit deadline in late 2030, as compared to those that must meet the second retrofit deadline in 2034. We seek comment on these draft rebate categories and dollar amounts, as well as the assumptions and methodology underlying these proposals. Given the lack of detailed supporting data in the current record, commenters recommending any adjustments are strongly encouraged to specify those changes in detail and provide supporting data, ( printed page 66132) documentation, and other record support for their recommendations.

Finally, we also seek comment on any other requirements or guidance the Bureau can consider in terms of relevant information, documentation, or procedures that will be helpful to eligible aircraft owners and operators and enable the Upper C-band Clearinghouse to equitably and expeditiously administer the rebates. For example, what records or other documentation (such as maintenance logs) would be available across different aircraft categories that would sufficiently establish that the FAA-mandated retrofits have been completed by the relevant deadline and could serve as support for a rebate claim filed with the Upper C-band Clearinghouse? Should aircraft owners and operators be advised to provide any additional detail in such records reflecting, for example, the number of radio altimeters per aircraft, type of retrofit work ( i.e., upgrade of an existing radio altimeter design, or installation of an entirely new design), and date of retrofit completion for each type of aircraft? What other documentation might supplement those records or serve as an alternative to achieve the same goals, such as detailed certifications by the eligible aircraft owner and operator? What information from other sources could be used to validate a claim (for example, the FAA maintains records regarding aircraft owner information associated with aircraft registrations, technical standard order authorizations for radio altimeters, and design approvals)? Commenters should address any documentation best practices that they suggest would both provide appropriate support for any rebate claim and enable the Upper C-band Clearinghouse to prevent any fraud, waste, or abuse in administering the rebates. Our intent in seeking comment on these matters is not to unduly constrain the Upper C-band Clearinghouse in developing any relevant claims processing procedures, but rather to develop a factual record and provide guidance to all stakeholders that will facilitate and expedite the administration of these rebates.

Consistent with the Upper C-band R&O, the Bureau will issue a public notice finalizing the rebate categories and amounts, as well as any other requirements and guidance, as soon as feasible.