The eXperimental Advanced Instructional Design Advisor (XAIDA) is one of the intelligent tutoring system (ITS) authoring tools presented at the AAAI 1997 Fall Symposium. This paper briefly describes the system including the Deliver (student mode) and Develop (authoring mode) components. Four shells are described although some exist only in a preliminary prototype. XAIDA is best used for creating tutors to teach maintenance of physical devices. Maintenance training is split into teaching the physical characteristics of the device, the theory of operation of the device, the procedural operations of the device, and troubleshooting problems with the device. Each of these shells is discussed in this paper.