What defines the combustion phase in an aircraft's operational cycle?

The combustion phase in an aircraft's operational cycle is primarily defined by the burning of the fuel-air mixture. During this phase, the fuel that has been mixed with air undergoes a chemical reaction when ignited, resulting in the release of energy in the form of heat and expanding gases. This energy is crucial as it generates the thrust required for the propulsion of the aircraft.

While the mixing of fuel and air is an important preliminary step in the combustion process, it is essentially a preparation stage and not the phase that defines combustion itself. The subsequent phases, such as the expulsion of exhaust gases and cooling of internal components, occur after combustion has taken place. Therefore, the essence of combustion is the ignition and burning of the fuel-air mixture, making it the defining phase in propulsion.