FAA NPRM Remote ID Is Close – Needs Work On Operations Under Part 91

On New Year’s Eve 2019, the FAA released their proposed rulemaking for UAS Remote ID. The proposal rule provides a sound framework for a critical issue in the expansion of drone use in the National Airspace System, remote identification of aircraft. However, in order to ensure the rapid and safe integration of unmanned aircraft with current airspace, the proposed rule requires some changes to the handling of operation under Part 91 (14 CFR 91), and ADS-B. Sagetech Avionics provided the following comments to the FAA to help improve the proposed rule:

Sagetech Avionics Comments on FAA NPRM

Sagetech Avionics appreciates the opportunity to provide public comments on the FAA NPRM for UAS Remote ID.  Sagetech Avionics’ mission is to enable UAVs to safely fly beyond visual line-of-sight in the National Airspace System.  Unmanned aircraft systems have the ability to provide significant positive economic impact, performance improvements and safety enhancements to many industries, and integration into the NAS should be done in such a way as to maintain the enviable safety record the US aviation community has enjoyed under the FAA’s administrative oversight.

NPRM Defines a Solid Framework for Integration of UAS

The NPRM reflects industry opinion well and defines a solid framework for integration of UAVs into most airspace.  However, changes to operations under Part 91 risk creating a decrease in the level of safety in airspace segments shared by manned aircraft, and delay integration of UAVs into those airspace segments.

US Controlled Airspace (source faa.gov). Operations under Part 91 occur in much of Class A, B, C, and E airspace, requiring UAVs to equip similarly to manned aircraft for safe integration.

Part 91 Changes Create Risk of Reduced Safety

The Part 91 rule changes introduce potential safety concerns regarding ATC and air-to-air traffic coordination and tracking. The NPRM does not address disconnected UTM and ATM systems, and the changes to Part 91 will make UAVs become “uncooperative” targets in the ATM.  UAVs are generally very difficult to see visually, and due to their small radar cross section and composite construction are also difficult to detect and track at any reasonable distance with air-to-air and ATC radar.  As a result, UAVs will be uncooperative and nearly invisible – stealth missiles in manned airspace.  This could have a detrimental effect on the safety of flight in Part 91 airspace.  ADS-B Out and Mode S transponders are designed to ensure that aircraft can sense and avoid each other, with or without the assistance of ATC, and should be required on UAVs in the same airspace as they are required on manned aircraft.  We believe the safest means to integrate UAS into Part 91 airspace is to leave equipment requirements as they are currently written and allow UAS operators to fly without an ATC Transponder and ADS-B Out only if an equivalent level of safety can be shown.

Part 91 Changes Delay the Introduction of UAS into National Airspace System

The Remote Identification NPRM combined with the recent Notice of policy for Type Certification of UAS make it clear that the FAA will control required and accepted equipage of unmanned aircraft, as it should.  However, the NPRM doesn’t specify equipment which would enable flight in controlled airspace, and the Part 91 changes eliminate the only current flight safety equipment available to UAS operators.  Without the Part 91 changes as written, UAVs could be equipped with the same safety equipment as manned aircraft, which would enable integration into controlled airspace shared with manned aircraft in the very near future.

Congestion on ADS-B Frequencies Can be Mitigated

In the proposed rulemaking document, the FAA cites a MITRE ADS-B System Performance Study (citation 78) and concluded from the study that ADS-B frequencies cannot support the projected number of UAS operations.  However, an equally valid conclusion that can be drawn from that same study is that low transmit power and traffic density parameters can be balanced to provide an acceptable ADS-B solution for UAS without congestion of the spectrum.  Dynamic transmit power management available in today’s technology can reduce spectrum use in high traffic density situations. MOPS are currently being written to reduce transmissions through limited Mode A and C responses by Mode S transponders, as well as modified TCAS whisper-shout sequences.  These technology and procedural changes will significantly reduce spectrum congestion, enabling UAVs to cohabit Part 91 airspace with the same equipment as manned aircraft, accelerating safe integration into the National Airspace System.

Summary

We believe the NPRM contains a well-defined framework for UAS operating at low altitude and in certain airspace segments.  With the elimination of the changes to Part 91, this new rule could help accelerate the realization of UAS benefits to industry and society, while maintaining the outstanding safety record of our National Airspace System.

We appreciate your consideration of Sagetech Avionics’ comments.

Sincerely,

Tom Furey, CEO
Sagetech Avionics, Inc.
28 February 2020