A well-designed user interface is recognized as a benchmark for determining the success of a software product. The proliferation of user interface design guidelines, standards, prototyping tools, and techniques are indicative of the importance placed on quality user interfaces. However, even with the availability of the latest information, tools, and human factors practitioners to software developers, sub-optimal interfaces may result. This is because within a large multidisciplinary software design team, issues such as communication, responsibilities, and cost and schedule constraints may override the usability issues. This paper describes the implementation of concurrent engineering, used to successfully develop user interfaces for a large, complex system. Success is expressed in terms of quality and consistent user interfaces, positive influence of human factors on software development, and customer satisfaction.