The Joint Common Architecture Demonstration (JCA Demo) project was the first in a series of planned experiments under the Joint Multi-Role (JMR) Technology Demonstrator (TD) Mission Systems Architecture Demonstration (MSAD) Science and Technology (S and T) effort. JCA Demo focused on maturating key standards, processes, and tools necessary for the acquisition of affordable, common, reusable avionics capabilities. These include the Future Airborne Capability Environment (FACE (trademark)) standard, JCA Functional Reference Architecture, Model-Based Engineering (MBE) and Architecture Centric Virtual Integration Process (ACVIP). Through a competitive model-based acquisition effort, two vendors were selected to develop are usable software component that the Army successfully integrated and demonstrated on two undisclosed mission computers. The JCA Demo approach of learning by doing resulted in dozens of actionable lessons learned that matured each of the standards, processes, and tools necessary to tackle complexity and affordability.