A small-scale gas turbine jet engine was studied to compare the sustainability performances at different part loads. To assess the performance of the jet engine, experiments are conducted at four different part loads (part load-1, part load-2, part load-3 and part load-4). According to the load types, the energy and exergy rates of the engine components were investigated. Sustainability indicators were used to analyze the jet engine. Parameters such as exergy efficiency, waste exergy ratio, exergy destruction factor, environmental effect factor and exergetic sustainability indicator were studied to understand the effects of four load types. The compressor, combustion chamber, turbine and nozzle are investigated. The maximum exergy efficiency of the jet engine took place at part load-3 as 7.8%. The minimum waste exergy ratio (0.9) and exergy destruction factor (0.9) were calculated at part load-4. The minimum environmental effect factor and maximum exergetic sustainability factor belong to part load-3 case. They were found to be 12.029 and 0.0831, respectively. The maximum exergy destructions were observed in the combustion chamber for all load types. They were found to be 48.96 kW, 57.14 kW, 67.93 kW and 74.38 kW, respectively.