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CHAPTER 3 The IT System Lifecycle-- A Common Process 3.1 Introduction This chapter introduces fundamental concepts of the IT system lifecycle that can be applied to the aviation industry. As implied by its name, the lifecycle is the process of managing the entire life of a system, from its conception through design, implementation, and ongoing operations until it is removed or replaced. Following a standard process in a deliberate, structured, and methodical way integrates people, data, and business systems from all areas of the airport and can generate a high-quality system that brings the following benefits: Meets or exceeds customer expectations. Reaches completion within time and cost estimates. Works effectively and efficiently within established IT principles and infrastructure. Is cost-effective to operate and maintain. Much has been written about system lifecycles, and many names have been applied to the phases and documentation that result from following a standard process. Regardless of the names, the lifecycle is a sequence of stages in which the output of each stage becomes the input for the next. There is no one definitive lifecycle model, but the stages generally follow the same basic steps, which, for the purposes of the primer, have been simplified into four key phases: Strategic planning System planning Implementation Operations and maintenance (O&M) Identifying requirements accurately and completely for a new system is vital to its successful implementation. Requirements are defined in progressively greater detail in each of the first three phases. At each phase, consensus between stakeholders and IT departments should be reached. The activities performed and the outputs of each phase are depicted in Figure 3-1. The reality of IT system lifecycle implementation is more complex than Figure 3-1 shows. People and departments cannot perform their tasks in isolation, and the activities do not flow sequentially, with one starting only after the previous one is finished. Many activities are carried out in an iterative process until all parties can agree on the outcome. The lifecycle portrayed here provides a common process that all organizations can implement to reduce time and costs, resolve conflicts faster, and create a commonly understood set of documentation supporting all systems. The following sections give a high-level description of each phase in the IT system lifecycle, including inputs, activities, and outputs. Outlines and templates of many of the lifecycle documents referenced in the text are included in Appendix A. 29