Various aspects of a multi-disciplinary aero engine conceptual design approach and computational framework are presented. The approach closely integrates different disciplines and is capable of homing in on the best designs in the presence of techno-economic and environmental risk. The framework can assist in the transition from the traditional, human-centered design procedure that involves complex manual iterations, to a more automated process. It considers the following disciplines: engine performance, engine aerodynamic and mechanical design, aircraft design and aerodynamic performance, emissions prediction and environmental impact, engine and airframe noise, and production, maintenance and direct operating costs. The proposed explicit conceptual design algorithm reduces system complexity, improves computational speed and can make design space exploration and optimisation results easier to interpret. Through a good set of constraints, it will also give an optimal aero engine conceptual design that may prove feasible in terms of major engine certification and customer requirements. The power of the proposed conceptual design approach has been demonstrated through a variety of unique case studies. These range from technology assessment and design sensitivity analysis to design space exploration and optimization. Overall, the work sets the necessary base for an assessment methodology that can quantify risks and assess the impact of gas turbine design on the environment, by comparing and helping to rank future technologies and design concepts for civil aviation on a formal and consistent basis.