Standard Specification for Detect and Avoid System Performance Requirements
|Publication Date:||1 May 2020|
This specification applies to unmanned aircraft (UA) with a maximum dimension (for example, wingspan, disc diameter) ≤25 ft, operating at airspeeds below 100 kts, and of any configuration or category. It is meant to be applied in a "lower risk" (low- and medium-risk airspace as described by Joint Authorities for Rulemaking on Unmanned Systems (JARUS)) airspace environment with assumed infrequent encounters with manned aircraft; this is typically in classes G and E airspace (below about 1200 ft above ground level (AGL)), Class B, C, D (below about 400 to 500 ft AGL), below obstacle clearance surface (FAA Order 8260.3, as amended), or within low altitude authorization and notification capability (LAANC) designated areas below the altitude specified in the facility map.
Traffic encountered is expected to be mixed cooperative and non-cooperative traffic, instrument flight rules (IFR) and visual flight rules (VFR), and to mostly include low-altitude aircraft-including rotorcraft, small general aviation, crop dusters, ultralights, and light sport aircraft, but not transport category aircraft.
This includes, but is not limited to, airspace where all aircraft are required2 to be cooperative (for example, within the Mode C veil in the U.S.).
Ultimate determination of applicability will be governed by the appropriate civil aviation authority (CAA).
This specification assumes no air traffic control (ATC) separation services are provided to the UA.
While some architectures may have limitations due to external conditions, this specification applies to daytime and nighttime, as well as visual meteorological conditions (VMC) and instrument meteorological conditions (IMC).
This specification is applicable to the avoidance of manned aircraft by unmanned aircraft systems (UAS), not UA-to-UA or terrain/obstacle/air
This specification does not define a specific detect and avoid (DAA) architecture3 and is architecture agnostic. It will, however, define specific safety performance thresholds for a DAA system to meet to ensure safe operation.
This specification addresses the definitions and methods for demonstrating compliance to this specification, and the many considerations (for example, detection range, required timeline to meet well-clear, and near mid-air collision (NMAC) safety targets) affecting DAA system integration.
The specification highlights how different aspects of the system are designed and interrelated, and how they affect the greater UAS system to enable a developer to make informed decisions within the context of their specific UAS application( s).
It is expected this specification will be used by diverse contributors or actors including, but not limited to:
DAA system designers and integrators,
Ground control station (GCS) designers,
UAS service suppliers, and
Flight control designers.
Except for DAA system integrators for whom all the "shalls" in this specification apply, not all aspects of this specification are universally relevant. Nonetheless, familiarity with the entire specification will inform all actors/contributors of how their contributions affect the overall DAA capability and is strongly recommended.
The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system are not necessarily exact equivalents; therefore, to ensure conformance with the standard, each system shall be used independently of the other, and values from the two systems shall not be combined.
This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.
This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2 Refer to 14 CFR § 91.215 and 14 CFR § 91.225 in the United States, or to the international equivalent for exceptions.
3 ACAS sXu is intended to serve as a reference architecture for this specification.