Unique Aspects of Unmanned Aerial Vehicle Testing

The purpose of this paper is to examine the applicability of established manned aircraft test techniques and processes to the testing of Unmanned Aerial Vehicles (UAVs). While the paper is largely focused on the Naval Aviation perspective, input from several joint programs as well as some Air Force and Army testing is included. In addition, although handled differently, the testing of the Tomahawk Cruise Missile is also considered. Processes associated with test planning, risk mitigation and airworthiness are considered in some detail. Much of this document is drawn from UAV flight test experience compiled in a draft Advisory Group for Aerospace Research and Development (AGARD) paper for the North Atlantic Treaty Organization (NATO) paper by the author. Given the enormous range in size, speed, and complexity of UAV systems examined, it is not surprising to find that numerous conclusions can be drawn. This paper attempts to categorize both the air vehicles and their associated systems to facilitate the analysis. There are many standard flight test techniques that can easily be applied to UAV systems with excellent results. The same is true of many of the processes associated with flight test planning and execution. However, it is also evident that it is beneficial and in many cases necessary to adapt, or tailor, both the techniques and the processes to efficiently test a given system. A prime example of modifying test techniques is evident with many of the smaller systems that cannot support the type of instrumentation normally associated with manned aircraft flight test. Similarly, with respect to processes, airworthiness requirements often need to be tailored in consideration of the actual risk, cost, capability and benefit provided by the system. By definition, testing of an unmanned vehicle presents no risk to the pilot/operator. If control by fail-safe, or flight termination device can eliminate risk to property, the robustness of the design can be far below what may be considered acceptable for a manned aircraft, without creating significant safety issues. Recommendations include process improvements to permit UAV programs to evolve without excessive restrictions based on manned aircraft requirements. These processes should be based on system’s characteristics and an assessment of the risks associated with the test and mission constraints of the system. Adaptation of evolving technology may be used to further refine and improve existing flight test techniques for UAV systems. Further research is recommended in the form of a statistical study of total UAV and cruise missile flight test mishaps, fatalities, and property damage as a function of total flight hours to validate the risk level and support process improvement