In-Depth Analysis of the Starting Process of Gas Turbine Engines

In-flight flame out of a gas turbine engine is one of the worst nightmares of the aviators. Relight of the engine is the most benign action possible to restore the safe flight. In such circumstances, the starting process is a vital issue that needs careful study. The starting phase of the gas turbine engine is a highly complex and transient phenomenon. It involves the core aero-thermal portion of the engine and systems such as ignition system, fuel system, and control system and in some extreme cases of relighting assistance from starter also required. As far as the turbomachinery is concerned, the starting phase is an off-design condition, except for the starter and ignition system. From the flight safety point of view, the importance of reliable engine start, especially the in-flight relight of aircraft engine needs no explanation and assurance about midair restart capability need to be proven beyond doubt. The methodology demonstrated in this paper is a novel tool that can be used by maintenance engineers to identify the impending failures of the starting system. This paper highlights the outcome of the work carried out for a detailed analysis of the starting process via the starting trials of turboprop engines. Based on the detailed study of the starting process carried out during initial aircraft integration of the turboprop engine, the authors could identify the faults in the starting system of turboprop engine in the ground which has an effect on safe and reliable air starts. In-flight relights data and ground starts data have been analyzed as a part of this study to identify the novelties in the starting process so as to detect the faults.