RTCA - DO-377A
Minimum Aviation System Performance Standards for C2 Link Systems Supporting Operations of Unmanned Aircraft Systems in U.S. Airspace
|Publication Date:||16 September 2021|
SCOPE OF THE DOCUMENT
In developing these standards, SC-228 used the following Systems, Operations, and Regulatory scope:
The C2 Link System is defined as the connection used to send information exchanges between a CS and a UA and to manage the connection between them. The scope of this standard is shown in the shaded box in Figure 1-1. The figure shows that the system includes only the functionality required to manage the Air/Ground and Ground/Ground links from the CS and the UA (Data Transfer, Security, and Routing, DTSR) and one or more possible links between the CS and the UA. Appendices B.5.2 and B.5.3 describe the various types of links that may be included in a C2 Link System, and Appendix B.5.1 describes how different types of links may be used operationally. A detailed explanation of DTSR functions is found in Appendix K.6. Consequently, this MASPS does not address the content, prioritization, acknowledgment, frequency, or any other aspect of the user data that flows over the links.
The scope of the operations considered all types of airspace used in the U.S. and Oceanic Airspace managed by the U.S. Air Traffic Organization (ATO). The strategy used in writing this MASPS was to focus on enabling operations that are in high demand today and then to use the knowledge gained while undertaking those operations to begin to build a more mature and comprehensive set of performance assessments that could then be applied in the future. More information on the airspaces covered in this MASPS is available in APPENDIX B. The specific CONOPS that were assessed are explained in detail in APPENDIX A, and the use cases and scenarios, are explained in APPENDIX B.
Federal Aviation Administration (FAA) regulations and procedures were used as a basis for determining the needed C2 Link System standards in this MASPS. The C2 Link System Operational Safety Assessment (OSA) in this MASPS is not intended to replace the complete UAS system safety analysis that is required by the FAA Type Certification Regulations (e.g., 14 CFR Part §25.1309 and Part §23.2500) but is intended to provide input into that system safety analysis. The OSA was used to support the development of the Operational Performance Assessment (OPA), and the OPA was used to create the requirements in Section 3.
Design Assurance Levels (DAL) are not specified in this MASPS. This document is intended to establish the acceptable level of risk for C2 Link System functionality in the airspace where the UA is operating. The appropriate level of design assurance will vary greatly based on many factors, including but not limited to the level of UAS automation, C2 Link System redundancy, airspace where the UAS is intended to operate, the kinetic energy of the UA, and the population density under the approved area of operations. The trade space created by this many variables makes it impossible to establish fixed design assurance levels. This document is intended to inform the UAS designer and C2 Link Service Providers how to create and obtain regulatory approval of designs that meet the acceptable level of safety risk for the UAS design and CONOPS.
This document is not applicable to UAS operations performed under the 14 CFR Part 107 regulations.