"Concurrency" is the word being used to describe the situation when a simulator or other aircrew training devices are required for delivery at the same time as the new aircraft it will support. If traditional acquisition approaches are applied to concurrent aircraft and simulation programs, it is practically impossible, in many cases, to deliver a fully capable aircrew training device anywhere near the Initial Operational Capability (IOC) of the aircraft. This is especially true when dealing with aircrew trainers for a complex tactical or strategic weapon system. Using the B-1B Simulator System program as an example, this paper discusses the risks and management challenges involved with concurrency and an innovative acquisition strategy designed to ensure the availability of aircrew training devices at or before the aircraft IOC. Included in this strategy are: 1) a new approach to preparation of the request for proposals documentation, 2) a competitive preliminary design effort, 3) methods for dealing with the acquisition of simulator design data, 4) the concept of providing the user a limited (interim) training capability early in the program, 5) management of a configuration baseline which evolves along with the simulator design, and 6) retrofit/update of all delivered devices to the final aircraft configuration.