In this work, the Techno-economic Environmental Risk Analysis framework, a multi-disciplinary optimisation tool developed by Cranfield University, is utilised in conjunction with an in-house optimiser to carry out aircraft engine cycle optimisation processes. The central point here is the evaluation of the capabilities of the in-house optimiser for performing this type of optimisation processes. Simplifying hypotheses are thus considered when both defining the aircraft flight trajectory and modelling the different engine configurations analysed. Accordingly, several optimum engine cycles minimising separately three objective functions, (i) specific fuel consumption in cruise, (ii) fuel burned, and (iii) oxides of nitrogen emitted, are determined. The cycle optimisation processes carried out yield results reflecting the general trends expected when optimising according to these objective functions. It follows then that the in-house optimiser is suitable for carrying out gas turbine power plant optimisation processes. It is expected that this optimiser be utilised in future for both optimising the preliminary design of gas turbine engines and determining optimum and “greener” aircraft engine cycles.