The phase of the development engineering life cycle in which the greatest risk traditionally emerges is that of integration and test, culminating in final acceptance. Attention is often paid to integration and test aspects too late to influence the earlier phases of the life cycle, where the seeds are sown for success or failure. This paper presents a strategy that actively addresses integration aspects as early as possible, to mitigate these risks, where possible, well ahead of commencement of the implementation of the integration phase. A multi-sensor Naval fire-control system is taken as an example, and this is used to focus on the essential elements of the strategy for the successful integration of Radar and EO sensors. These include: design for integration, a robust and accurate method of aligning the sensors, and test cases which reflect the in service usage of the system. The methods of alignment both in the dockyard and at sea are described, together with a threads analysis approach to determining system functionality, user operational requirements and hence determining system functional test coverage. Finally conclusions are drawn, comparing the classical approach to the one described in the paper, showing the benefits to de-risking the engineering life cycle and achieving an in-service system which has the functionality and performance the user is expecting.