Development of a Process to Define Unmanned Aircraft Systems Handling Qualities

Unmanned Aircraft Systems (UAS) are no longer coming, they are here, and operators from first responders to package delivery are demanding access to the National Airspace System (NAS) for a wide variety of missions. This includes a proliferation of small UAS or sUAS that will operate beyond line of sight at altitudes of 500 ft and below. A myriad of issues continues to slow the development of verification, validation, and certification methods that will enable a safe introduction of UAS to the NAS. These issues include the lack of both a consensus on UAS categorization process and quantitative certification requirements including the definition of handling qualities. Because of the wide variety of UAS types (fixed wing, rotary wing from traditional helicopters to multi-rotor configurations, ducted fans, airships, etc.) and vehicle sizes, from micro vehicles to the Global Hawk with a wing span similar to that of a Boeing 737, there cannot be a one-sizefits-all set of requirements. To address these issues, a team led by Systems Technology Inc. is developing a process that will guide UAS stakeholders through a systematic handling qualities evaluation process. This work builds on the existing, highly successful, military rotorcraft handling qualities specification that features a mission-oriented approach. In the proposed process, the vehicle is first identified by a weight-based classification and then the associated vehicle missions or use cases are considered. These missions have specific tasks that dictate the criteria and demonstration maneuvers necessary to evaluate handling qualities. An assessment of both modeled responses and flight test data can then be conducted to examine the predicted versus actual handling qualities. A mismatch points to the need for refined models as flight is the ultimate check of handling qualities.