Availability is one of the key performance indicators for repairable systems, usually expressed as the average proportion of time the system is in a state capable of performing the required function.  Availability can be enhanced by increasing the reliability and/or reducing the restoration time of components. In the design phase, a mathematical method is applied to optimize the availability improvement (or target) at the component level with some relevant constraints such as cost and complexity. This paper is a continuation of the work carried out by the authors to address such mathematical aspects.  System design is a multidisciplinary activity subject to “conflict of interest” among stakeholders such as system integrator, equipment supplier, and operator.  The focus of this paper is to extend the previous work by looking into availability allocation from the perspective of systems engineering. Systems engineering is a systematic approach to enable the realization of a successful solution. The paper uses a systems engineering methodology to demonstrate its applicability as an integral part of the availability allocation process.  The conclusion is that a systems engineering methodology can be applied successfully such that the system availability target and the stakeholders’ needs can be met.