scope:

Introduction

This document provides the Operational Services and Environment Description (OSED) for the RTCA Special Committee 228 (SC-228) Unmanned Aircraft System (UAS) Detect and Avoid (DAA) Minimum Operational Performance Standards (MOPS). The purpose of this OSED is to provide a basis for assessing and establishing operational, safety, performance, and interoperability requirements for DAA systems.

Because there is no human operator onboard an Unmanned Aircraft (UA) looking out the window of a cockpit, a DAA system is being standardized in order to establish an acceptable alternative means of compliance with applicable standards. These include Title 14 (Aeronautics and Space) of the United States Code of Federal Regulations (14 CFR), 91.111, 91.113, and 91.181, and Section 2.3.1 of the International Civil Aviation Organization (ICAO) Annex 2 to the Convention on International Civil Aviation. The DAA system is used to avoid nearby aircraft (hereafter referred to as "intruders"). This OSED for DAA uses the term "remote pilot" throughout to describe the person acting as the remote pilot of the UA and manipulating the flight controls. This OSED does not attempt to allocate responsibility for specific DAA tasks to individual members of the flight crew; instead, the OSED assumes a single remote pilot. Remote pilot and crew training for a specific DAA system may allocate responsibilities differently.

This OSED describes using a MOPS-compliant DAA Class 1 through Class 8 system with sensors onboard and/or offboard a UA operating under Instrument Flight Rules (IFR) while transiting through Class B, Class C, Class D, Class E up to Flight Level (FL) 180, or Class G airspace conducting extended operations in Class D, E, and G airspace. The addition of DAA equipment Class 5 also enables operations in the Terminal Area during approach and departure in Class C, D, E, and G airspace and off-airport locations. DAA functionality as specified in this OSED is not expected to be required for operations within Class A, Class E above FL180, or Special Use Airspace (SUA), although DAA equipment may remain on and Class 2 and Class 3 Resolution Advisories (RAs) will be followed. This includes Traffic Alert and Collision Avoidance Version 2 (TCAS II) or Airborne Collision Avoidance System X for Unmanned aircraft (ACAS Xu).

Optional equipment classes enable lower Size, Weight and Power (SWaP) onboard non-cooperative sensors, Terminal Area alerting and guidance, and Ground Based (GB) surveillance equipment.

This OSED for DAA does not directly apply to UAS operations under 14 CFR Part 101 or 107. UA performance is covered by RTCA DO-365.

The guiding RTCA Special Committee 228 (SC-228) Terms of Reference (TORs),¹ and this OSED focus on both airborne DAA systems with sensors onboard the UA and GB surveillance equipment.

The scenarios in this OSED expand upon the Federal Aviation Administration (FAA) UAS Concept of Operations (CONOPS),² and provide additional operational detail necessary for DAA MOPS development.

In developing the services and environment description, the OSED for DAA identifies numbered Operational Assumptions (ASSUMP-OSED.##) and Operational Requirements (OR.##), which are necessary to bound the scope of the document. Operational Assumptions, while important, do not establish a requirement upon the system or other actors in the environment. Operational Assumptions establish the environment under which this document and the associated requirements are valid. While Operational Requirements do establish requirements, the object of the requirement will always be an actor "external to the DAA system" (e.g., requirements on training or responsibilities for remote pilots or Air Traffic Control (ATC) personnel). Operational Requirements contain the word "shall" and the requirement text and surrounding paragraphs will identify the external actor or system which is expected meet the intent of that requirement. DAA System Requirements are developed in the DAA MOPS and ACAS Xu MOPS; Surveillance System Requirements are developed separately in their respective MOPS (e.g. airborne RADAR requirements are developed in the Air-to-Air RADAR MOPS).

The OSED assumes that a DAA system can be built and integrated with other ground and avionic systems as proposed in Operational Views depicted in Section 2 using DAA architectures developed in Section 3. The OSED for DAA references MOPS, MASPS, and other standards where specific functionallity is required to achieve the envisioned operational capability. The referenced standards contain the system, subsystem, and interface requirements which achieve the capabilities developed in this OSED for DAA.

¹ Terms of Reference for RTCA Special Committee 228 Minimum Performance Standards for Unmanned Aircraft Systems Rev 10, 11 June 2020

² Federal Aviation Administration (2012). Integration of Unmanned Aircraft Systems into the National Airspace System, Concept of Operations V2.0, 28 September 2012