With fewer and fewer exceptions, the Department of Defense is requiring Ada to be the sole programming language for all new software-related projects. In addition, these new projects are expected to achieve higher levels of maintainability from a software perspective. Experience shows that these seemingly unobtrusive requirements manifest themselves in a very large variety of unforeseen challenges and implicit requirements. This paper overviews an Ada real-time flight simulation environment based on an implementation for the B-2 Aircrew Training Device (ATD) and the challenges encountered in going from concept to product. Three areas of challenge are involved in building this environment. The first concerns the control of software units distributed across processors and groups of processors. Another area of concern is providing input/output services to all units in Ada, which even the operating system does not readily support. The third area covers selected obstacles encountered in developing a pure Ada implementation of a system to support unit interfaces. The resultant real-time environment represents an effective blend of Ada and traditional techniques.