The purpose of this paper is to share how the quantity and quality of data available For propulsion system management greatly increases with the use of digital technology engine monitoring hardware. A previously unobtainable data base for maintenance decisions is available from the use of diagnostic monitoring systems. Artificial intelligence methods are being successfully used to provide improved data presentation and interpretation. The computational capability of the digital technology allows reduction of in-flight data into referred diagnostic values from deviations in engine performance. Although referred diagnostic data may not detect all potential engine problems, this available capability, with its artificial intelligence, has demonstrated the ability to identify hidden problems, which greatly enhances propulsion system management. This paper will present details of several current applications to both military and civilian helicopters with the idea that the demonstrated capability to improve operational reliability is potentially essential to maximize flight safety and control operating costs.