The simulation of aircraft is probably one of the most complicated yet exciting field in the engineering world today. A performance simulation program for the turboprop engine(PT6-62), which is the power plant of the first Korean indigenous basic trainer KT-1, was developed for performance prediction, development of an EHMS(Engine Health Monitoring Systems)and the flight simulator[1]. Characteristics of components including compressors, turbines, power turbines and the constant speed propeller were required for the steady state and transient performance analysis with on and off design point analysis. At on-design condition , the object of cycle analysis is to obtain estimates of the performance parameters (primarily thrust and specific fuel consumption) in terms of design limitations(such as maximum allowable turbine temperature and attainable component efficiencies), the flight conditions (the ambient pressure, temperature and Mach number), and design choices(such as compressor pressure ratio, fan pressure ratio, etc.). moreover, at off-design condition, the object of off-design cycle analysis is to determine estimates of an engine’s performance over its operating envelope. Then, an engine cycle and its design conditions are selected so, the results of the off-design cycle analysis are used to size the engine. The independent variables in off-design are flight conditions, throttle setting, and nozzle settings. This program which provide by FORTRAN program, investigate some performance parameters such as mass flow rate, compressor pressure ratio, fuel flow rate, specific fuel consumption and turbine inlet temperature versus various altitudes and flight Mach number. The successive substitution method was used to calculate off-design analysis while in on-design condition no iteration required for solution due to all of the design choices are free to be selected by the designer and the engine performance characteristics per unit mass flow are determined for each selected set of choices.

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