The US Federal Aviation Administration (FAA) plans to issue a request for comments on May 25 2023 from industry on its plans to expand beyond visual line of sight (BVLOS) drone operations. In its draft Docket No.: FAA-2023-1256 UAS Beyond Visual Line-of-Sight Operations publication the FAA is planning to review its approach to recognising detect and avoid (DAA) standards and the considerations around third-party suppliers offering DAA services.
According to the draft report (text which follows is taken directly from the draft document):
“As the FAA reviews the recommendations of the UAS BVLOS Operations Aviation Rulemaking Committee (ARC), the FAA is considering the expansion of BVLOS operations in certain operating environments with the appropriate safety mitigations to ensure no adverse safety impact. The FAA is seeking comment to gather additional technical input on key concepts and potential approaches that the FAA is contemplating for use in future exemptions.
In this document, the FAA seeks public comments that address how advances in technology, standards, and operational strategies to safely demonstrate UAS BVLOS operations can be applied without adversely affecting safety.
Detect and Avoid Systems Performance Standards
The FAA recognizes that several industry standards have been published that may be useful in defining the performance of Detect and Avoid (DAA) systems, a major component of BVLOS operations. However, any single standard may not be fully appropriate for the uses intended by applicants operating at and below 400 feet above ground level (AGL). Therefore, the FAA is reviewing these standards, as well as ways for operators to demonstrate that their DAA system meets specific requirements in a combination of published standards. These include:
- ASTM F3442/F3442M-23, Standard Specification for Detect and Avoid System Performance Requirements, dated February 28, 2023.
- RTCA DO-381, Minimum Operational Performance Standards (MOPS) for Ground Based Surveillance Systems (GBSS) for Traffic Surveillance, dated March 26, 2020.
- RTCA DO-365C, Minimum Operational Performance Standards (MOPS) for Detect and Avoid (DAA) Systems, dated September 15, 2022.
- RTCA DO-396, Minimum Operational Performance Standards for Airborne Collision Avoidance System sXu (ACAS sXu), dated December 15, 2022.
- A1. In which circumstances or operating environments should the FAA allow this combination approach?
- A2. Conversely, are there circumstances or operating environments where no combination of current standards would provide an acceptable level of safety?
Declarations of Compliance for Detect and Avoid
As the FAA is contemplating operations beyond visual line of sight, the FAA is considering allowing operators to declare that they are utilizing DAA systems that meet the DAA standard(s) referenced above.
- B1. In which circumstances or operating environments should the FAA allow this declaration approach? What supporting documentation or data should the FAA require prior to authorization to operating under an exemption?
- B2. Conversely, are there circumstances or operating environments in which the FAA should require operators to submit details of their DAA system for approval and validation prior to operation?
Well clear boundary
ASTM F3442/F3442M-23, Standard Specification for Detect and Avoid System Performance Requirements, referenced previously, suggests maintaining a horizontal distance of 2,000 feet and a vertical distance of 250 feet between a small UAS and crewed aircraft, described as a “hockey-puck-shaped” area of airspace surrounding the small UAS.
- C1. In which circumstances or operating environments would this standard be appropriate?
- C2. If not this standard, what well-clear boundary should the FAA consider for operations under an exemption, and under what circumstances or operating environments?
DAA systems that include Third-Party Services / Associated Elements (AE)
There are numerous technologies and architectures that may be suitable when implementing DAA solutions. Some systems may have sensors and DAA logic that are fully contained onboard the aircraft with information relayed to the pilot control station. A remote pilot may be involved in executing avoidance maneuvers, or may monitor the aircraft’s automated response. Other systems may rely on ground-based sensors that are connected to, but distinct from, the UA and its control station. Yet other DAA systems may use a combination of those approaches. Under 14 CFR 1.1, a UAS is defined as the UA and its associated elements necessary to support the safe flight of the UA. However, in various petitions for exemptions, the FAA has understood some DAA system components are intended to be reused by multiple operators. These components are generally not directly controlled by either the UAS manufacturer or the operator; rather, they are controlled by a third-party service provider. Third-party services may directly support the DAA solution by, for example, detecting crewed aircraft in a defined geographic region, or by relaying such information through a managed command and control (C2) link on behalf of multiple operators.
Therefore, the FAA is considering new ways to evaluate and recognize these components as distinct elements. Additionally, section 377 of the FAA Reauthorization Act of 2018 (Pub. L. 115-254) directs the Administrator to “determine if certain UTM [Unmanned Aircraft Systems Traffic Management] services may operate safely in the national airspace system before completion of the implementation plan required by Section 376.”
- D1. The FAA is considering separating the UTM service provider approval from the exemption for relief from parts 91 and 61. In order to operate, the UTM service provider would need to receive its approval, and the applicant’s exemption would be contingent on use of an approved service. Other operators seeking to use that same service would present their specific use case with the approved UTM service. Should the FAA separate the approval of the UTM service provider from the exemption? Why or why not?
- D2. Conversely, the FAA is also considering including the approval of the UTM service within the exemption, similar to how the FAA has implemented 49 U.S.C. 44807 to date. Should the FAA consolidate these approvals? Why or why not?
Use of UTM Services for Strategic Deconfliction
At present, the FAA has not determined an acceptable level of risk for collision between two UA. However, FAA is concerned that with increasing numbers of BVLOS UAS operations, two UA could collide, resulting in falling debris that could cause property damage, injuries, or fatalities to non-participants on the ground.
- E1. One proposal the FAA is considering would be to require all BVLOS operations in controlled airspace or within the lateral limits of a Mode C Veil under an exemption to use a strategic deconfliction and conformance monitoring capability (both terms as described in FAA’s UTM Concept of Operations v2.0). This could be fulfilled if the operator provisions their own capability that meets the requirements of a published standard; or by using a UTM service. Should the FAA impose this requirement? Why or why not?
- E2. Alternatively, the FAA is considering requiring all BVLOS operations under an exemption, including in Class G airspace, to use a strategic deconfliction and conformance monitoring capability. Should the FAA impose this requirement? Why or why not?
- E3. The FAA is aware of one published standard that could be used to meet a requirement to have a strategic deconfliction and conformance monitoring capability. It is referenced as ASTM F3548-21, Standard Specification for UAS Traffic Management (UTM) UAS Service Supplier (USS) Interoperability, dated March 8, 2022. What alternative means exist, preferably using published standards, that the FAA should consider? What evidence exists for the safety benefit and operational efficiency of any alternative means?
Detect and Avoid Between Unmanned Aircraft
FAA views strategic deconfliction and conformance monitoring as two layers of a new, conceptual conflict management strategy for UAS. The FAA is also considering requiring a third layer, in the form of detect-and-avoid between UA, leveraging some form of vehicle-to-vehicle communications method.
- F1. One proposal would be to use the ACAS sXu standard (RTCA DO-396). What communications method should be used in conjunction with this approach? Should the FAA impose this requirement, including use of a specific communications method? Why or why not?
- F2. What evidence exists that the requirement in the above question would sufficiently manage the risk of collision between UA? Should such a requirement be in addition to, or in lieu of, any requirement to use strategic deconfliction and conformance monitoring?
- F3. If the FAA imposes a requirement for UA-to-UA DAA, should it also prescribe technical requirements to ensure interoperability of the solution across all BVLOS UAS? Why or why not?
Beyond Visual Line of Sight Shielded Operations
The BVLOS ARC report proposed labeling certain type of BVLOS operations as shielded operations. These operations would occur in a shielded area defined by the ARC as “a volume of airspace that includes 100’ above the vertical extent of an obstacle or critical infrastructure and is within 100 feet of the lateral extent of the same obstacle or critical infrastructure as defined in 42 U.S.C. 5195(c).” Furthermore, the ARC recommended that shielded operations be given right-of-way privileges based on the unique nature of those operations and the limited likelihood of crewed aircraft operations in the specified areas. The FAA is considering a similar framework based on safety analysis and some ability to detect and avoid crewed aircraft operations.
- G1. In which circumstances or operating environments should the FAA authorize shielded operations? The 42 U.S.C. 5195(c) definition of critical infrastructure has a broad applicability. Should the FAA further limit or expand the applicability?
- G2. Conversely, are there circumstances or operating environments in which the FAA should not authorize shielded operations?
- G3. The ARC report describes the appropriate offset as 100’ above, and 100’ lateral. Is this the appropriate standard? Why or why not? If not, what other standard should be used, and what evidence exists for the appropriateness and safety of an alternative standard?
- G4. What type of notification (e.g. email/phone call, web portal, mobile phone application using UTM services, etc.) should operators conducting BVLOS shielded operations provide to the local aviation communities?
The final text of the document may differ from this draft
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