The reuse of embedded software has presented a significant challenge in aviation, as the FAA must certify all software each time it is installed in airborne systems. As part of the FAA certification process, any embedded Operating System or software solution must meet the rigorous RTCA/DO-178B guidance document. Considerable engineering effort is required to comply with the DO-178B document. Often, many verification tasks are repeated when software is redeployed increasing schedule, risk and cost. A new FAA policy (AC 20-148) released in December 2004 allows for reuse of DO-178B credit that can be applied across software and hardware platforms. This paper documents the technical and economic benefits of applying AC 20-148 using an operating system. A brief review of RTCA/DO-178B is given along with FAA certification policies. A fully time and space partitioned operating system is used as an example in the paper.