The Use of Case-Based Reasoning Technology to Aid Fault Isolation in a Modern Gas Turbine Engine Design
Volume 5: Manufacturing Materials and Metallurgy; Ceramics; Structures and Dynamics; Controls, Diagnostics and Instrumentation; Education
The increasing numbers of commercial decision support tools based on Case-Based Reasoning (CBR) technology reflects the interest in the use of this technology to aid fault diagnosis, not only in gas turbine applications but also in the wider engineering domain. CASSIOPEE from CFM and ARIADNE from British Airways are but two examples of these types of support tool in the civil gas turbine engine arena. They reflect the trend of developing such systems from a historical database of maintenance
... e of maintenance arisings and necessarily apply to older engine designs. Further characteristics of which include older and less sophisticated aircraft maintenance systems, which provide limited diagnostic information and rely more heavily upon the experience of maintenance personnel to isolate engine faults successfully. It is this diagnostic experience which these CBR tools have attempted to capture and emulate; the case for a CBR-based tool in this instance is well proven. More recent aircraft design have resulted in a more comprehensive on-board maintenance systems to aid maintenance personnel diagnose airframe and engine faults. Such an approach should rely less heavily upon the experience of the maintenance crew to isolate a fault successfully. The paper reports on the design and development of two CBR-based maintenance decision support tools for the Rolls-Royce Trent 800 and RB21 1-524 engines. One system is currently undergoing a trial to refine the design of the maintenance case base (the database over which the CBR engine searches to match the current fault symptoms to a historical event). The lessons learned from this field trial and future prospects for such a CBR-based maintenance aid are discussed.