Modernizing Spectrum Rules for Advanced Air Mobility
On January 13, 2025, the Federal Communications Commission adopted a Notice of Proposed Rulemaking (FCC 25-7) in WT Docket No. 24-629 aimed at modernizing service and technical rules across three spectrum bands to facilitate the integration and deployment of Advanced Air Mobility (AAM) and Uncrewed Aircraft Systems (UAS). The document was formally released on January 17, 2025.
The Commission's proposals address spectrum frameworks for 650 kilohertz in the 450 MHz band, 200 megahertz in the 24.45–24.65 GHz band, and 4 megahertz in the 800 MHz Commercial Aviation Air-Ground Systems band. By resolving and incorporating petitions for rulemaking filed by AURA Network Systems OpCo, LLC/A2G Communications, LLC (RM-11912), Echodyne Corporation (RM-11819), and Gogo Business Aviation LLC (RM-11985), the Commission seeks to enable safe, flexible, and robust communications and detection infrastructure for aviation technologies.
- WT Docket No. 24-629; FCC 25-7 adopted on January 13, 2025, and released on January 17, 2025.
- Grants in part and terminates rulemaking petitions RM-11912, RM-11819, and RM-11985.
- Establishes a public comment period ending 30 days after Federal Register publication, with reply comments due 60 days after publication.
450 MHz Band: Nationwide Licensing and UAS Command and Control
The Commission proposes to update the 454.6625–454.9875 MHz and 459.6625–459.9875 MHz bands (650 kHz total) by adding a non-federal primary Aeronautical Mobile (Route) Service (AM(R)S) allocation. This allocation would permit control and non-payload communications for uncrewed aircraft systems (UAS CNPC), expanding beyond existing legacy voice-only Air-Ground Radiotelephone Service (AGRAS) rules.
To eliminate regulatory barriers and white spaces caused by legacy distance-separation requirements, the FCC proposes transitioning from site-based licensing to a single geographic nationwide license covering the contiguous United States, Alaska, Hawaii, and U.S. territories. A voluntary transition mechanism would allow a 'covered incumbent' meeting specific eligibility criteria—namely providing coverage at 25,000 feet over CONUS, Alaska, and Hawaii—to modify its authorizations into the nationwide license.
The proposed rules define a 15-year license term with interim (4-year) and final (8-year) performance benchmarks measured across Regional Economic Area Groupings (REAGs). Licensees could fulfill buildout obligations through high-altitude (25,000 feet) and low-altitude (400 feet) combinations or dedicated low-altitude coverage tiers.
- Adds primary non-federal AM(R)S allocation for UAS CNPC.
- Proposes a single 650 kHz nationwide exclusive geographic license with a 15-year term.
- Removes legacy 20 kHz channelization and 800 km co-channel ground transmitter separation rules.
- Applies out-of-band emissions limits attenuated by at least 43 + 10 log (P) dB at legacy band edges.
24.45–24.65 GHz Band: Secondary Radiolocation for UAS Detection
To enhance airspace security and situational awareness, the Commission proposes adding federal and non-federal secondary allocations for radiolocation in the 24.45–24.65 GHz band. This band is currently allocated co-primarily to radionavigation and inter-satellite services.
The proposed secondary radiolocation allocation is intended to permit ground-based radar systems to detect and track UAS around sensitive locations, including borders, prisons, critical infrastructure, and stadiums. The proposal builds upon waiver relief previously granted to entities such as Echodyne Corporation and MatrixSpace, Inc., and technical reviews of authorized radar equipment, including equipment certified under FCC ID 2ANLB-MESASSR00053.
The Commission proposes to license these operations under Part 90 on a site-based, ten-year renewable license framework, applying Emission Mask B (§ 90.210(b)) and requiring standard Part 90 equipment authorizations.
- Adds federal and non-federal secondary radiolocation allocations to the 24.45–24.65 GHz band.
- Facilitates ground-based counter-UAS surveillance without altering primary radionavigation priority.
- Applies Part 90 site-based licensing, ten-year terms, and Emission Mask B out-of-band emissions limits.
- Requires transmitters to obtain formal equipment authorization under Part 90 rules.
800 MHz Commercial Aviation Air-Ground Systems Power Modernization
For Commercial Aviation Air-Ground Systems operating in the 849–851 MHz and 894–896 MHz bands, the Commission proposes modernizing legacy power rules that currently measure effective radiated power (ERP) strictly on a peak power basis. Under the existing § 22.867, peak ERP is capped at 500 watts for ground stations and 12 watts for airborne mobile stations.
The NPRM proposes transitioning to an average power measurement technique accompanied by a 13 dB Peak-to-Average Ratio (PAR) limit and implementing a Power Spectral Density (PSD) model. This change aligns commercial air-ground rules with those in adjacent and similar commercial mobile services (such as PCS, AWS, and Cellular), allowing modern wideband modulations like Orthogonal Frequency Division Multiplexing (OFDM) to operate at efficient average power levels without artificial constraints from brief peak power spikes.
Additionally, the FCC proposes eliminating obsolete rules, including § 22.853 spectrum aggregation limits and § 22.859 legacy transition rules, while adding commercial air-ground systems to the station identification exemption list under § 22.313.
- Proposes replacing peak power limits with average ERP regulation in the 849–851 MHz and 894–896 MHz bands.
- Proposes a 13 dB Peak-to-Average Ratio (PAR) limit applied across occupied bandwidth.
- Proposes implementing a Power Spectral Density (PSD) model to accommodate wideband digital waveforms.
- Eliminates obsolete provisions including §§ 22.853 and 22.859 and updates station identification rules in § 22.313.