Although the title of this paper, for brevity, refers to engine performance monitoring, in fact we mean performance and condition monitoring. In presenting such a paper with particular emphasis on the problems that arise for the Operator with relatively small aircraft fleets operating in the main over short stages, although the comments we have to make are based on TAA experience, a similar situation must exist for any operator with a multiplicity of aircraft types and relatively small numbers of each.

We refer to performance and condition monitoring to define the complete task, as it is essential to correlate performance parameters to condition evidence such as vibration level or lubricant deterioration status to obtain a useful perspective.