Design considerations for systems hosted on integrated modular avionics

System architects are accustomed to developing systems hosted in federated environments that allow for developmental independence. However, the system boundaries are different when systems are hosted in an Integrated Modular Avionics (IMA) platform. The boundaries lie within shared resources, and thus lead to greater dependencies between systems. This drives new design considerations for system architects. The natural tendency is to leverage traditional federated design concepts when building systems for IM1A environments, but this can lead to inefficient use of system resources, and a lack of preparedness for the inevitable change that will occur within the integrated set of systems. NMA has become a standard in the civil and military aviation industries, so it is important to understand these new design considerations. The question addressed by this paper is "What unique design considerations are there for systems hosted on an IMA platform ?" All of the considerations can be attributed to three main drivers present in the IMA environment: * 1) optimization of system resources across the integrated set of hosted systems, * 2) change containment when hosted systems change, and * 3) change containment when the NMA platform elements change (technology insertion). These three factors impact the traditional developmental independence between systems since it requires the architect to consider their system\´s role within the integrated set of systems. They must now consider how they will tolerate changes that are out of their control, such as changes to other hosted systems or the IMA platform that affect the shared resource performance. They must now consider how they contribute to the efficient use of system resources as part of the greater system-wide optimization strategy. If these factors are not addressed, then it can lead to wasted system resources, increased development costs, and high costs-of-change. Therefore the incentive to ensure that these new design consi- derations are addressed lies with both the system integrator who owns the integrated set of systems and the architect of each hosted system. This is based upon the authors\´ experience in developing 11%A systems at GE Aviation. GE Aviation has developed open system 11%A architectures for commercial aircraft (Boeing 787 Dreamliner), as well as military aircraft (Boeing C-130) combat aircraft, and Boeing KC-767 Tanker).