47 C.F.R. § 88.135 – DFMS requirements.

(a) A DFMS must provide a process for NNA users to register with the system for the purpose of submitting frequency assignment requests and obtaining frequency assignments.
(b) All DFMSs must require the same registration and frequency assignment request information. Registration shall require, among other information, the registrant's legal name and contact information.
(c) A DFMS must be capable of processing frequency assignment requests nationwide and across the entire 5030-5091 MHz band. However, a DFMS may only grant assignments for spectrum within those frequencies specified under § 88.29(a).
(d) In response to a frequency assignment request from a registered party, a DFMS shall determine and provide, through a process that is highly automated and capable of rapid responses to frequency assignment requests, an assignment of frequencies for a particular geographic area and time period tailored to the submitted UAS flight, to the extent that frequencies are available to meet the request and grant of the assignment is otherwise consistent with this part. Assignments must provide protected access to frequencies over a duration and geographic area sufficient to cover and support the entire UAS flight. Assignments may specify channels and maximum transmit power level.
(e) A DFMS may not terminate an assignment while a flight is ongoing or modify the assignment during this time unless pursuant to a revision request from the assignee.
(f) Assignments must account for the need to protect other authorized operations.
(g) Models and methodologies for interference determinations used by a DFMS should be both effective in avoiding harmful interference and consistent between different DFMSs.
(h) For each frequency assignment request, a DFMS must confirm through certifications in the frequency assignment request process that the requesting party has flight authorization from the FAA to cover the flight associated with the frequency assignment request, and that any remote pilots that will be involved in the flight have all necessary FAA remote pilot authorization, to the extent such authorization is required. Any party challenging a DFMS action with regard to this requirement or otherwise seeking a Commission determination regarding a party's FAA authorization in this context must submit, with its filing to the Commission, a determination from the FAA regarding whether the NNA frequency assignee in question has the relevant authorization under FAA rules and requirements.
(i) A DFMS must be capable of responding to in-flight revision requests.
(j) A DFMS must be capable of communicating directly with a UAS ground station operating in the NNA spectrum, or with proxy software acting on the ground station's behalf, to achieve the following:
1. (1) ensure that all NNA stations used in an operation, including any ground or airborne station used in the flight, are programmed to limit communications in the 5030-5091 MHz band, during the period of the frequency assignment, to the specific frequencies assigned by the DFMS and in accordance with the other terms of the assignment; and
2. (2) receive updates on flight status when a UA has launched and when it has landed.
(k) Frequency assignment requests may not be approved:
1. (1) for periods commencing on or after eight calendar days after the date on which the request is submitted, except to the extent that lack of frequency availability in that time frame or the coordination requirement under § 88.35 justify a later assignment; or
2. (2) for an operation lasting more than 24 hours.
(l) A DFMS must communicate and coordinate with other DFMSs as necessary to ensure consistent data and assignments, the safe and robust operation of authorized services, and compliance with the rules.
(m) A DFMS must employ protocols and procedures to ensure that all communications between the DFMS and users or NNA stations in connection with a DFMS's NNA functions are secure and that unauthorized parties cannot access, shut down, or alter the DFMS or its stored information.
(n) Communications between users and a DFMS and between different DFMSs must be secure to prevent corruption or unauthorized interception of data. A DFMS must be protected from unauthorized data input or alteration of stored data.
(o) A DFMS must verify that the NNA stations to be used in operations are FCC-certified devices and must not provide assignments to an uncertified device.
(p) A DFMS must retain information on, and enforce, exclusion zones sufficient to protect Microwave Landing Systems (MLS) in the 5030-5091 MHz band.
(q) A DFMS shall maintain all records for at least 60 months, including but not limited to date, time, and requester identification records for all requests for, approval of, denial of, or termination of approval for all assignments of frequencies or revisions of such assignments, and all certifications submitted in connection with such requests.
(r) A DFMS must be capable of receiving reports of interference and requests for additional protection from MLS users in the 5030-5091 MHz band or authorized users in adjacent bands and promptly address interference issues.
(s) A DFMS must implement § 88.35 in its frequency assignment process.
(t) A DFMS must implement the terms of any international agreements with Canada and Mexico adopted to address coordination and compatibility of near-border UAS operations in the 5030-5091 MHz band.
(u) Except as provided under paragraphs (v) and (w) of this section, a DFMS must process frequency assignment requests on a non-discriminatory first-come-first-served manner.
(v) In the event of emergencies, a DFMS should, to the extent feasible and consistent with the interests of aviation safety, prioritize requests from public safety entities. Prioritization may not terminate or modify an NNA user's assignment while the assignment is in use during a UAS flight.
(w) During extended periods of congestion, the DFMS should prioritize requests involving flights relying on a single ground station over requests that rely on multiple stations, to the extent feasible and consistent with the interests of aviation safety.

(x) A DFMS must immediately notify the National Science Foundation, Division of Astronomical Sciences, Electromagnetic Spectrum Management Unit, by email at esm@nsf.gov when a request for frequency assignment is approved that will support operation of a UAS within 25 miles of a radio astronomy site listed in table 1 to this section. Notification must include the operation details.

Table 1 to § 88.135
Allen Telescope Array, Hat Creek, CA	Rectangle between latitudes 40°00′ N and 42°00′ N and between longitudes 120°15′ W and 122°15′ W.
NASA Goldstone Deep Space Communications Complex, Goldstone, CA	80 kilometers (50 mile) radius centered on 35°20′ N, 116°53′ W.
National Astronomy and Ionosphere Center, Arecibo, PR	Rectangle between latitudes 17°30′ N and 19°00′ N and between longitudes 65°10′ W and 68°00′ W.
National Radio Astronomy Observatory, Socorro, NM	Rectangle between latitudes 32°30′ N and 35°30′ N and between longitudes 106°00′ W and 109°00′ W.
National Radio Astronomy Observatory, Green Bank, WV	Rectangle between latitudes 37°30′ N and 39°15′ N and between longitudes 78°30′ W and 80°30′ W.
National Radio Astronomy Observatory, Very Long Baseline Array Stations	80 kilometers radius centered on:
	North latitude	West longitude
Brewster, WA	48°08′	119°41′
Fort Davis, TX	30°38′	103°57′
Hancock, NH	42°56′	71°59′
Kitt Peak, AZ	31°57′	111°37′
Los Alamos, NM	35°47′	106°15′
Mauna Kea, HI	19°48′	155°27′
North Liberty, IA	41°46′	91°34′
Owens Valley, CA	37°14′	118°17′
Pie Town, NM	34°18′	108°07′
Saint Croix, VI	17°45′	64°35′
Owens Valley Radio Observatory, Big Pine, CA	Two contiguous rectangles, one between latitudes 36°00′ N and 37°00′ N and between longitudes 117°40′ W and 118°30′ W, and the second between latitudes 37°00′ N and 38°00′ N and between longitudes 118°00′ W and 118°50′ W.

Effective Date Note:At 90 FR 1395, Jan. 8, 2025, Part 88 was added, and § 88.135 was delayed indefinitely.