The scope of this study is analyzed and discussed in detail for better understanding of energetic performance of a low bypass turbofan engine. In this regard, this study presents first law of thermodynamics of the turbofan engine for maximum thrust level. The engine has low-pressure compressor (LPC) stages, high pressure compressor (HPC) stages, a single HP turbine (HPT), and finally three LPT stages. The results show that energy flow approaches a maximum value to be 73.76 MW in the combustor outlet, while minimum energy flow is observed at fan bypass outlet with the value of 5.60 MW. Accordingly, temperature, pressure and mass flow of the engine components are also calculated from Brayton cycle equations. As a consequently, engine energetic parameters, namely specific fuel consumption and engine overall efficiency, are also calculated for the low bypass turbofan engine from this study.