Modified start sequence of a gas turbine engine

A system for starting a gas turbine engine of an aircraft, the system comprising:

• a pneumatic starter motor;
• a discrete starter valve switchable between an on-state and an off-state;
• a controller operable to perform a starting sequence for the gas turbine engine, the starting sequence comprising alternating on and off commands to an electromechanical device coupled to the discrete starter valve to achieve a partially open position of the discrete starter valve to control a flow from a starter air supply to the pneumatic starter motor to drive rotation of a starting spool of the gas turbine engine below an engine idle speed;
• an electronic engine control system comprising:
• a memory for recording a current heat state of the gas turbine engine at shutdown and for recording a shutdown time of the gas turbine engine;
• and
• a risk model for determining a time period (tmotoring) for motoring the gas turbine engine at a predetermined speed Ntarget wherein the predetermined speed is less than a speed used to start the gas turbine engine and wherein tmotoring is a function of the heat state recorded at engine shutdown and an elapsed time of an engine start request relative to the previous shutdown time.