The objective of the work reported herein was to use a systems engineering approach to guide development of integrated instrumentation/sensor systems (IISS) incorporating communications, interconnections, and signal acquisition. These require enhanced suitability and effectiveness for diagnostics and health management of aerospace equipment governed by the principles of Condition-based maintenance (CBM). It is concluded that the systems engineering approach to IISS definition provided clear benefits in identifying overall system requirements and an architectural framework for categorizing and evaluating alternative architectures, relative to a bottom up focus on sensor technology blind to system level user needs. CBM IISS imperatives identified include factors such as tolerance of the bulk of aerospace equipment operational environments, low intrusiveness, rapid reconfiguration, and affordable life cycle costs. The functional features identified include interrogation of the variety of sensor types and interfaces common in aerospace equipment applications over multiplexed communication media with flexibility to allow rapid system reconfiguration to adapt to evolving sensor needs. This implies standardized interfaces at the sensor location (preferably to open standards), reduced wire/connector pin count in harnesses (or their elimination through use of wireless communications). 1. Scope, Objectives, and Methods This article paper the instrumentation and sensors employed to support condition-based maintenance (CBM) of aerospace equipment, sensing the condition of equipment and components (state and operation) needed to enable diagnostics triggering necessary maintenance actions. It encompasses such instrumentation and sensors, plus the signal acquisition function and the intervening communication media, thus “integrated instrumentation/sensor systems” [IISS]. The focus is on IISS application to diagnostics and health management (DHM) enabling more cost effective CBM for the complex mechanical systems required for propulsion & power, environmental control, flight control, and other essential functions that are weight and volume constrained, tightly integrated with other systems and vehicle structure, and exposed to the full rigors of the flight envelope and environment. Modern aerospace equipment control systems include many control sensors that may also serve CBM functions. However, IISS are being proposed and deployed for aerospace equipment diagnostics and health management (DHM) (as described by Urban [1], Litt et al. [2], and Paris et al. [3]) to
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