This paper proposes a component-based design pattern for distributed automation programs. This design pattern aims to improve reusability of programs and reduce redevelopment time. Component-based design issues in both IEC 61131-3 and IEC 61499 platforms are analyzed. Then the design pattern is proposed in a form of a set of rules. The pattern combines properties of service-oriented architecture (SOA) with multi-layered organization and engineering benefits of component organization. This design pattern is applied to both IEC 61131-3 and IEC 61499 on example of a real airport baggage handling automation system. The result proves that the design pattern brings convenience for developers of automation programs and improves reusability of software components.