Section 107.52 ATC transponder equipment prohibition
Unless otherwise authorized by the Administrator, no person may operate a small unmanned aircraft system under this part with a transponder on.
FAA’s Commentary from 2020 Amendment to Part 107 on Section 107.52 ATC transponder equipment prohibition
4. Prohibition against the Use of ADS-B Out and Transponders This rule prohibits use of ADS-B Out and transponders for UAS operations under 14 CFR part 107 unless otherwise authorized by the FAA, and defines when ADS-B Out is appropriate for UAS operating under part 91. The FAA is concerned the potential proliferation of ADS-B Out transmitters on unmanned aircraft may negatively affect the safe operation of manned aircraft in the airspace of the United States. The projected numbers of unmanned aircraft operations have the potential to saturate available ADS-B frequencies, affecting ADS-B capabilities for manned aircraft and potentially blinding ADS-B ground receivers. Therefore, unmanned aircraft operators, with limited exceptions, are prohibited from using ADS-B Out or transponders. The prohibition against the use of ADS-B Out and transponders is discussed in section XVII of this preamble.
A number of commenters believed remote identification requirements for UAS are stricter than ADS-B Out or transponder requirements for manned aircraft. Several commenters suggested permitting UAS operations without remote identification in uncontrolled airspace and away from airports, similar to the requirements for ADS-B Out that only apply in certain airspace. Commenters also stated that manned aircraft should be required to broadcast ADS-B Out in all airspace if all UAS are required to transmit remote identification. Several commenters also noted that manned aircraft were offered grants and rebates to help cover the cost of ADS-B implementation and had over 10 years to equip for ADS-B Out compared to the shorter implementation time proposed for remote identification.
FAA Response: The FAA acknowledges the significant number of comments opposing the proposed regulation and related policies. After further consideration of public comments, the FAA has modified some of the remote identification policies in the final rule, as further discussed throughout this preamble, to reduce the burdens on unmanned aircraft operators and producers while maintaining the necessary requirements to address the safety and security needs of the FAA, law enforcement, and national security agencies. The FAA does not agree with commenters who believed remote identification will harm innovation in the UAS industry. On the contrary, the Agency believes that this performance-based regulation provides opportunities for innovation and growth of the UAS industry by addressing the security concerns associated with unmanned aircraft flight at night and over people. In addition, the FAA does not agree that the remote identification requirements are stricter than ADS-B Out requirements. Remote identification has fewer technical requirements compared to ADS-B, and this rule provides accommodations for unmanned aircraft operations without remote identification.
Some commenters mentioned that UAS operations receiving air traffic services should be required to use ADS-B Out. Other commenters such as the Aerospace Industries Association, Airbus UTM, the Association for Unmanned Vehicle Systems International (AUVSI), General Atomics Aeronautical Systems, and Northeast UAS Airspace Integration Research mentioned that the proposed rule did not clearly state that UAS authorized by the FAA to use ADS-B Out or transponders are excepted from meeting the operating rules in part 89.
Unmanned aircraft equipped with ADS-B Out. The FAA agrees with the commenters who stated that certain UAS operating under air traffic control and equipped with ADS-B Out and ATC transponders are already meeting the intent of the remote identification rule, and that remote identification may be redundant for such operations. The FAA adopts an exception to the remote identification operating requirements in § 89.101(b) for persons conducting unmanned aircraft operations under part 91 that are transmitting ADS-B Out pursuant to § 91.225. Operators of unmanned aircraft that meet the criteria are not required to comply with the operating requirements of part 89. The operation may be conducted under any type of flight plan that is acceptable for the intended operation. The FAA has provided a similar exception from the remote identification production requirements for unmanned aircraft certified under a part 21 design or production approval that are equipped with ADS-B Out. Notwithstanding the exception in § 89.101(b), nothing in this rule precludes unmanned aircraft from being equipped with both ADS-B Out and remote identification equipment. However, to ensure that unmanned aircraft do not place a strain on the ADS-B system, ADS-B Out may not be used to meet remote identification requirements outside of those unmanned aircraft operations for which it is required. The use of ADS-B Out in transmit mode is restricted to those unmanned aircraft operations for which it is required.
Comments: AERO Corporation supported the requirement to broadcast, and suggested a remote identification transponder similar to ADS-B Out.
FAA Response: The FAA notes that broadcast equipment, while somewhat similar in general concept to ADS-B Out, is also different in many significant ways. Moreover, as detailed in section XVII of this preamble, ADS-B Out is not a form of remote identification.
XVII. ADS-B Out and Transponders for Remote Identification
A. Discussion of the Final Rule
The FAA proposed to prohibit the use of ADS-B Out equipment as a form of remote identification of UAS under part 89. The FAA also proposed changes to parts 91 and 107 to generally prohibit the use of ADS-B Out and transponders on UAS, unless otherwise authorized.
The FAA adopts § 89.125, ADS-B Out prohibition as proposed, with minor edits for clarity. This prohibits the use of ADS-B Out equipment as a form of remote identification under part 89.
The FAA adopts the proposed modifications to § 91.215, which state that ATC transponder and altitude-reporting equipment and use requirements do not apply to persons operating unmanned aircraft, unless the operation is conducted under a flight plan and the person operating the unmanned aircraft maintains two-way communication with ATC, or the use of a transponder is otherwise authorized by the Administrator. In addition, § 91.215(e)(2) prohibits the use of ATC transponders by persons operating unmanned aircraft unless the operation is conducted under a flight plan and the person operating the unmanned aircraft maintains two-way communication with ATC, or the use of a transponder is otherwise authorized by the Administrator.
The FAA adopts the modifications to § 91.225(a)-(f) and (i) with some additional revisions for clarification. Per this section, no person may operate an unmanned aircraft under a flight plan and in two-way communication with ATC unless that aircraft has equipment installed that meets the performance requirements in TSO-C166b or TSO-C154c, and the equipment meets the requirements of § 91.227
In addition, § 91.225(i)(2) prohibits the use of ADS-B Out equipment by persons operating unmanned aircraft unless the operation is conducted under a flight plan and the person operating that unmanned aircraft maintains two-way communication with ATC, or the use of ADS-B Out is otherwise authorized by the Administrator.
Lastly, the FAA adopts §§ 107.52 and 107.53 as proposed, which prohibit the use of ADS-B Out and ATC transponders on small UAS. Under § 107.52, no person may operate a small UAS under part 107 with a transponder on, unless otherwise authorized by the Administrator. Under § 107.53, no person may operate a small UAS under part 107 with ADS-B Out equipment in transmit mode unless otherwise authorized by the Administrator.
B. Public Comments and FAA Response
Comments: Many commenters supported prohibiting ADS-B Out on UAS to prevent high volumes of UAS traffic using ADS-B Out from interfering with ADS-B used by manned aircraft and Air Traffic Control (ATC). Multiple commenters wanted to ensure that the use of ADS-B Out on UAS must first be proven not to interfere with manned aircraft before being widely allowed. They asked the FAA to continue to monitor radio frequency spectrum concerns if some UAS are authorized to use ADS-B Out by exception. They also noted that ADS-B Out does not accommodate sharing all of the proposed message elements. Airlines for America recommended that the FAA clearly state that UAS remote identification is prohibited from interfering with existing electronic surveillance technologies used for manned aircraft, and that the FAA consider permitting the use of ADS-B Out for more sophisticated UAS operations near commercial airports and manned aircraft.
FAA Response: The FAA agrees with commenters that supported prohibiting ADS-B Out on most UAS due to the likelihood that the high density of UAS operations compared to manned aircraft may generate signal saturation and create a safety hazard for manned aircraft. The FAA notes that unmanned aircraft remote identification equipment broadcasting in the frequency bands allowed under 47 CFR part 15 is prohibited by FCC regulations from interfering with existing, licensed frequencies used by existing surveillance technologies.
Comments: Many commenters also supported limited exceptions permitting ADS-B Out on larger UAS operating at higher altitudes and participating in ATC services. Some commenters challenged the FAA to justify remote identification requirements for unmanned aircraft that fly at higher altitudes. Boeing and other commenters recommended permitting ADS-B Out in lieu of remote identification for UAS operating primarily above 400 feet and not operating under 14 CFR part 107 (e.g., part 91, part 135). AERO Corporation recommended permitting the use of ADS-B Out on UAS operating above 400 feet under 14 CFR part 91, 107, or 135. The General Aviation Manufacturers Association recommended allowing ADS-B Out or transponder use for UAS of sufficient gross weight, based on the operations being performed.
The National Business Aviation Association agreed with prohibiting ADS-B Out and transponders on low altitude UAS such as those operating under 14 CFR part 107, but recommended clarifying the regulations to ensure UAS are not operating at higher altitudes typically used by manned aircraft while transmitting remote identification that is not directly available to manned aircraft. They recommended the FAA consider specifying UAS operations that are permitted or required to use ADS-B Out or a transponder instead of authorizing by exception, such as for UAS operating at higher altitudes, under a flight plan, or in communication with Air Traffic Control. Johns Hopkins University Applied Physics Lab asked the FAA to clarify that use of “ADS-B Out” in this proposal specifically refers to current use of 978 and 1090 MHz and does not preclude potential future systems on alternate frequencies that may meet remote identification requirements.
FAA Response: The FAA agrees with commenters that recommended permitting use of ADS-B Out instead of remote identification equipment by unmanned aircraft that are participating in ATC services and are likely to be integrated with manned aircraft, or by limited exception. For this reason, persons operating unmanned aircraft equipped with ADS-B Out, when operating under a flight plan and where the operator is in communication with ATC, do not have to meet the remote identification requirements in part 89. This is consistent with a recommendation by the UAS-ID ARC. Unmanned aircraft not operated in this specific manner must be equipped with remote identification unless authorized by the Administrator as permitted by § 89.105, which is being finalized to permit such exceptions on a case-by-case basis.
In response to the comment regarding future systems or alternate frequencies for ADS-B, the FAA notes that any changes to the current ADS-B Out equipment performance requirements, which include the 978 and 1090 MHz broadcast frequencies, would require a separate rulemaking activity and are outside the scope of this final rule.
Comments: Many commenters said that the rule does not clearly state that UAS authorized by the FAA to use ADS-B Out or transponders are excepted from meeting part 89 remote identification requirements. They suggested that remote identification would be unsuitable for use at traditional manned aircraft altitudes as well as unnecessary and redundant on UAS specifically approved to use ADS-B Out. Garmin similarly stated that requiring remote identification for UAS equipped with ADS-B would be unnecessarily duplicative.
FAA Response: The FAA agrees with commenters, and finalizes a change to § 89.101 which clarifies that the unmanned aircraft remote identification requirements do not apply to persons operating unmanned aircraft when the unmanned aircraft is equipped with ADS-B Out and operated in accordance with § 91.225.
However, as explained in section XIV.E.1 of this preamble, nothing in the rule precludes producers from producing unmanned aircraft that have both the remote identification and ADS-B capabilities identified in the regulation. Therefore, depending on the operation, with a few exceptions, unmanned aircraft must comply with remote identification requirements when the operation does not qualify for use of ADS-B Out under § 91.225. Operations that do qualify for use of ADS-B Out must comply with § 91.225.
Comments: Many commenters wanted the FAA to mandate the use of ADS-B Out on UAS instead of remote identification. Commenters objected to the FAA’s rationale that ADS-B Out is not appropriate due to infrastructure issues (ground radars and ADS-B receivers) and noted that remote identification will also require substantial new infrastructure, such as Remote ID USS, UAS equipment, and potentially greater internet coverage. Other commenters suggested that ADS-B Out should be a permitted option to meet the remote identification requirement.
FAA Response: In the NPRM, the FAA explained the range of considerations that influenced its decision not to propose ADS-B Out as a solution for unmanned aircraft remote identification, including coverage at low altitudes and the absence of any information about the control station location. The FAA declines to require the use of ADS-B Out as the means of providing unmanned aircraft remote identification. The FAA reiterates that the ADS-B system serves a unique purpose of enabling surveillance for air traffic control purposes while remote identification enables the FAA, law enforcement, and the public to identify unmanned aircraft and locate their operators. Due to the prospects of signal saturation and the differences in the types of information being shared, ADS-B Out is not a suitable alternative for remote identification equipment.
Comments suggesting that a greater number of receiver sites and software patches to limit ATC display clutter could address the issue with ADS-B Out were found to be impractical, in terms of both the time and the cost necessary to develop them. Further, they would not address the fundamental issues of signal saturation and insufficient message elements that made ADS-B unsuitable for remote identification. In addition, the FAA notes that the remote identification requirements, as being finalized, no longer require the referenced USS network infrastructure for the time being.
Comments: Several commenters were concerned about punishing UAS operators who were early adopters of ADS-B Out, and suggested permitting ADS-B Out or similar broadcast remote identification devices that are interchangeable between multiple UAS. AT&T Services asked the FAA to permit ADS-B Out on UAS responding to emergencies, noting that their UAS providing emergency cellular service in disaster areas currently use ADS-B Out to share UAS location information with manned emergency aircraft. The Academy of Model Aeronautics proposed permitting a single ADS-B Out unit to identify an FAA-recognized identification area so manned aircraft and other UAS are aware of active model aircraft operations. They also proposed pairing this with ADS-B In and a warning system at some locations so members would be alerted when cooperative manned aircraft are in the area.
FAA Response: The FAA has determined that ADS-B Out as presently implemented for surveillance purposes is inadequate to meet unmanned aircraft remote identification requirements. This rule includes provisions in §§ 89.105 and 91.225 to permit use of ADS-B Out on unmanned aircraft on a case-by-case basis as authorized by the Administrator. The FAA declines to require the use of ADS-B Out to identify an FAA-recognized identification area because it was not intended to be used to identify physical locations where UAS may be operating without remote identification.
Comments: One commenter expressed concern about the volume of UAS users that will be transmitting on Wi-Fi frequencies as well as range and altitude coverage on these frequencies.
A commenter was concerned about future expansion of manned aircraft operations if ADS-B Out radio frequency spectrum could be saturated by UAS, and suggested the ADS-B Out system be upgraded to support UAS operations as well. Another commenter suggested requiring ADS-B Out in remote, uncontrolled airspace where is it unlikely to cause frequency saturation, and requiring network remote identification in controlled and urban airspace where data and cellular coverage is readily available.
FAA Response: Regarding broadcast on Wi-Fi frequencies, the FAA notes that, by FCC rule, 47 CFR part 15 devices, including those used for the remote identification broadcast, may not cause harmful interference and must accept any interference received. In addition, remote identification equipment may not cause harmful interference to the unmanned aircraft command and control datalink or otherwise be in violation of FCC regulations. Unmanned aircraft remote identification equipment broadcasting in the 47 CFR part 15 radio frequency spectrum is also prohibited from interfering with existing, licensed frequencies used by existing surveillance technologies. With regard to the use of ADS-B Out in less dense environments where signal saturation would not be as likely a hazard, the FAA emphasizes that the ADS-B message set does not provide an indication of the control station location which is one of the reasons that ADS-B is not a suitable alternative.
Comments: Some commenters, including the Aviators Code Initiative, suggested that UAS operating under part 91 and future Urban Air Mobility (UAM) operations be required to use ADS-B Out unless future frequency saturation issues develop or remote identification is proven to be an adequate substitute for these operations.
FAA Response: The FAA partially agrees with comments that suggest ADS-B use is appropriate for unmanned aircraft operating under part 91 and UAM operations, and adopts the requirements necessary for unmanned aircraft to operate with ADS-B Out instead of remote identification. The FAA believes that the performance-based requirements in this rule provide multiple technical solutions for unmanned aircraft remote identification and support the evolution of remote identification solutions as UAS technology evolves.
Comments: A number of commenters challenged the FAA to justify its position that ADS-B functionality as a whole would be adversely impacted by a sharp increase in ADS-B users. uAvionix noted that radio frequency spectrum studies to date have focused on UAS operating in high traffic density below 400 feet AGL, but there are no studies at higher altitudes. uAvionix and Sagetech Avionics stated the part 91 prohibition introduces the possibility of non-cooperative part 91 UAS unless otherwise required to equip with remote identification (or “otherwise authorized by the Administrator” to use ADS-B Out or transponders). uAvionix, McInflight Aerospace, Sagetech Avionics, and NBAA recommended considering alternatives such as ADS-B Out. They also noted these licensed frequencies would be more reliable than 47 CFR part 15, Remote Identification Frequencies.
FAA Response: In the NPRM, the FAA referenced a study titled “ADS-B Surveillance System Performance with Small UAS at Low Altitudes” as the basis for proposing that an ADS-B Out solution for unmanned aircraft remote identification would cause adverse impacts to the existing ADS-B surveillance system. The FAA agrees with the analysis and information contained in this study. Related comments suggesting that lower-power ADS-B Out transmitters could be developed to meet remote identification requirements, accompanied by additional receiver sites and software patches to limit ATC display clutter, were found to be impractical, both in terms of the time and the cost necessary to develop them. The FAA agrees with commenters concerned about the possibility of non-cooperative unmanned aircraft in areas where remote identification is required, and notes that in accordance with § 89.101, part 89 applies to all unmanned aircraft operations except for those unmanned aircraft operations under part 91 of this chapter that are transmitting ADS-B Out pursuant to § 91.225.
Comments: Many commenters noted that both UAS and manned aircraft would benefit from shared situational awareness if UAS were equipped with ADS-B Out, which would provide UAS position information to manned aircraft pilots (and vice versa) via ADS-B In. Another commenter recommended that all manned aircraft and commercial UAS be required to equip with ADS-B Out (and ADS-B In for UAS), while permitting recreational UAS without remote identification to operate in Class G airspace.
Several commenters suggested that UAS remote identification and location information should be available to operators via the ADS-B In system, similar to current traffic and weather information, and noted a potential risk of reduced collision prevention capability because remote identification and ADS-B systems do not share information. Several manned pilots objected to needing to purchase new equipment to gain access to UAS remote identification information after already being required to purchase ADS-B equipment.
A number of commenters discussed potential safety advantages associated with UAS equipping with ADS-B In as a means of remaining well clear of all ADS-B Out equipped aircraft. Several commenters suggested that ADS-B In should be required or optional for UAS, either in general or specifically for larger UAS or for UAS capable of BVLOS such as delivery operations, and the National Agricultural Aviation Association noted that ADS-B In for UAS remains essential.
FAA Response: As the FAA stated in the NPRM, the primary purpose of UAS remote identification is to identify UAS operating in the airspace and provide an indication of the location of the operator. The FAA discussed other potential uses of remote identification information, such as situational awareness or future aircraft separation applications.
The FAA recognizes the benefit of shared situational awareness and encourages unmanned aircraft operators to equip with ADS-B In for increased traffic awareness, if practicable. The FAA notes that ADS-B In is not required equipment for aircraft operations under part 91, and any changes to require ADS-B In for manned or unmanned aircraft are outside the scope of this rule.
Comments: Commenters suggested that the proposed rule would implicitly force operators to purchase additional equipment, such as transmitters or transponders, which could cost about $100 to $500.
FAA Response: The FAA agrees that operators with a desire to operate beyond the boundaries of an FAA-recognized identification area will be required to purchase broadcast equipment of some kind (i.e., standard remote identification unmanned aircraft or a remote identification broadcast module). The FAA expects that the incremental cost to a consumer will range between $20 and $50 per unit. The FAA determined remote identification facilitates compliance with this rule and meets the safety and security needs of the FAA, national security agencies, and law enforcement.
III. REQUIRING ADS-B OUT
The FAA could have required transponders or ADS-B Out for unmanned aircraft as a means to identify those aircraft remotely. The FAA is prohibiting the use of transponders or ADS-B Out for remote identification of unmanned aircraft operations, with limited exceptions, for two primary reasons. First, the FAA expects that, due to the volume of unmanned aircraft operations projected, the additional radio frequency signals would saturate the available spectrum and degrade the overall cooperative surveillance system. Second, transponders and ADS-B Out do not provide any information about the location of control stations or takeoff locations, as these systems were designed for manned aircraft. For these reasons, the FAA has determined that existing cooperative surveillance systems are incapable of supporting unmanned aircraft remote identification. In addition, there would be a higher cost to equip under this alternative compared to the rule. The cost to equip unmanned aircraft with transponders and ADS-B Out would be $3,999 per aircraft.
Current rules for registration and marking of unmanned aircraft facilitate the identification of the owners of unmanned aircraft, but normally only upon physical examination of the aircraft. Existing electronic surveillance technologies, like transponders and ADS-B, were considered as potential solutions for the remote identification of unmanned aircraft but were determined to be unsuitable due to the lack of infrastructure for these technologies at lower altitudes and potential saturation of available radio frequency spectrum. Currently, the lack of real-time data regarding unmanned aircraft operations affects the ability of the FAA to oversee the safety and security of the airspace of the United States, creates challenges for national security agencies and law enforcement entities in identifying threats, and impedes the further integration of UAS into the airspace of the United States. The FAA addresses the identification issues associated with UAS by requiring the use of systems and technology to enable the remote identification of unmanned aircraft.