Gross starting characteristics of the Vericor Power Systems ETF40B gas turbine engine utilizing diesel fuel for the Republic of Korea Navy LSF-II application indicate inconsistent starting performance, especially in cold ambient temperatures. There is also evidence that cold starting inconsistencies exist on the US Navy LCAC installation of the ETF40B engine. The inconsistencies include late light-offs, failed starts, excessive exhaust smoke, detonative ignition and excessive commanded fuel flow by the full authority digital engine control (FADEC). The starting anomalies experienced on US Navy LCAC have ultimately resulted in the addition of starting requirements to the production engine acceptance test procedure. A detailed review of historical information regarding the TF40B fuel system characteristics resulted in the basis for establishing revised LFMV calibration values and revised FADEC engine start fuel scheduling. Additionally, this review indicated the need for fuel system flow/pressure measurements in order to establish current characteristics and to help refine component requirements and changes (as appropriate). These measurements are required over the entire engine starting and operating range. Cold ambient temperature start testing was performed to establish the engine start characteristics on JP5/JET A fuels with the existing and revised LFMV calibrations. A revised start schedule was developed that provided a reliable, stable starting characteristic (reliable first attempt starting, reducing smoking on starts, eliminating detonative ignition, minimizing large variations in commanded fuel flow during starting). The fuel system pressures and flows were fully characterized in the start and operating regime and start testing validation was performed on Diesel Fuel.
