## 4 Discussion  
TCL1 lessons learned: timeline and complexity. With the complex set of NASA/UAF hardware and software components and interfaces, the overall UTM system proved to have a somewhat steep learning curve. A number of challenges presented themselves as the team worked to establish initial connectivity, primarily dealing with computer network communications settings at a remote location new to the UAF team. In addition, there were also some challenges with learning nuances of the NASA software. Some of this difficulty would have been lessened with a longer timeline for integration. However, as with any new complex system, the software suite itself must undergo an evolution as it moves from the development phase into operations. It is expected that the user interface for the suite of these software products will undergo significant learning and modification as a result of the experiences of UAF and the other test site teams involved in TCL1. TCL2 lessons learned/recommendations: One of NASA's primary purposes for conducting the effort was to gain experience in how UAS teams might learn and utilize the UTM system in an increasingly complex environment. As such, UAF put much emphasis on creating scenarios that would generate sufficient complexity to simulate the higher level of UAS traffic reflected in this phase of UTM operations involving simultaneous operations with multiple UAS, personnel, and flight profilesfor each day of the campaign. By design, the more complex scenarios at times stressed the team's ability to operate several simultaneous, coordinated missions using different UAS assets. Adding to the complexity was the learning curve posed by both the prototype NASA UTM and USS client interface, which provided NASA with insights into challenges that might be faced by novice users of the fielded UTM system. NASA was sensitive to developing the UTM system in a fashion that seeks to minimize impacts on the operational community. To this end, NASA embedded human factors personnel within the test site teams to evaluate the impacts firsthand. In support, UAF provided an open window into the operations planning/conduct cycle so that NASA might observe a team learning how to work within the new constraints imposed by the system, as well as discovering potential benefits. A summary of observations/lessons learned and recommendations for the future follows:  
* UTM functionality: At the beginning of the campaign, personnel had little experience with either the UTM system or a USS client interface. As the campaign progressed, UAF demonstrated the ability to successfully learn and utilize the NASA UTM system through our USS provider (Simulyze). The team was able to develop new tools for the UTM/USS interface that make it more powerful and user friendly. A few examples included: (1) the collaborative state, which allows multiple UAS to launch/operate/recover in the same airspace; (2) the pause state, which allows UAS missions requiring multiple flights (typically limited by battery endurance) to retain the airspace versus releasing it between each flight (and risk losing it to another user); and (3) feedback on internal naming conventions and features of the tool. * UTM operator workload: The centralized UTM approach adopted by UAF for this effort placed a higher workload on the UTM POC. This was amplified for missions involving simultaneous operations by several UAS. While this was expected during the training/learning phase for new UTM operators, it was still a factor at times when very experienced UTM POCs were at the helm. Individuals did show rapid adaption to the environment and tasks, but they were still challenged at times with the workload associated with more than a few UAS. As expected, workload capacity and efficiency increased for everyone once the team exercised together a few times. * UAS crew concept/workload: All communications were accomplished through the flight director to the central UTM POC.