GAS TURBINE ENGINE AND OPERATING METHOD

A method of controlling a gas turbine engine (10). The gas turbine engine (10) comprises a compressor (14), a combustor (16), and a motor (28) configured to drive the compressor (14). The method comprises, in a first idle mode, controlling combustor (16) fuel flow to maintain compressor (14) rotational speed (N2) at or above a predetermined value; and in a second idle mode, controlling the combustor and the motor (28) to drive the compressor (14) to maintain the compressor rotational speed (N2) at or above a second predetermined value, lower than the first predetermined value.