An engine assembly comprising: a multi-spool combustion turbine engine including a high pressure spool which includes a high pressure portion of a compressor and at least one lower pressure spool ; a plurality of offtakes powered by the combustion turbine engine , at least one of the plurality of offtakes configured to selectively take power from the at least one lower pressure spool ; and a controller configured to operate the combustion turbine engine through a range between a first low-idle mode, a second high-idle mode, and a maximum takeoff power rating mode; wherein the controller is configured to operate the engine in the low-idle mode by directing at least a first portion of power from the at least one lower pressure spool to the plurality of offtakes , and wherein the controller is configured to operate the engine in the high-idle mode by increasing a speed of the high pressure spool relative to a speed of the high pressure spool in the low-idle mode, thereby increasing a compressor outlet T 3 temperature in the high-idle mode relative to a compressor outlet T 3 temperature in the low-idle mode; characterised in that : the controller is configured to operate the engine in either the high-idle mode or the low idle mode on taxi-in and is configured to operate the engine in the low-idle mode on taxi-out; and in that a selection of the low-idle mode or high-idle mode on taxi-in depends at least in part on an expected turnaround time of the engine between a taxi-in and a following taxi-out. a multi-spool combustion turbine engine including a high pressure spool which includes a high pressure portion of a compressor and at least one lower pressure spool ; a plurality of offtakes powered by the combustion turbine engine , at least one of the plurality of offtakes configured to selectively take power from the at least one lower pressure spool ; and a controller configured to operate the combustion turbine engine through a range between a first low-idle mode, a second high-idle mode, and a maximum takeoff power rating mode; wherein the controller is configured to operate the engine in the low-idle mode by directing at least a first portion of power from the at least one lower pressure spool to the plurality of offtakes , and wherein the controller is configured to operate the engine in the high-idle mode by increasing a speed of the high pressure spool relative to a speed of the high pressure spool in the low-idle mode, thereby increasing a compressor outlet T 3 temperature in the high-idle mode relative to a compressor outlet T 3 temperature in the low-idle mode; characterised in that : the controller is configured to operate the engine in either the high-idle mode or the low idle mode on taxi-in and is configured to operate the engine in the low-idle mode on taxi-out; and in that a selection of the low-idle mode or high-idle mode on taxi-in depends at least in part on an expected turnaround time of the engine between a taxi-in and a following taxi-out. the controller is configured to operate the engine in either the high-idle mode or the low idle mode on taxi-in and is configured to operate the engine in the low-idle mode on taxi-out; and in that a selection of the low-idle mode or high-idle mode on taxi-in depends at least in part on an expected turnaround time of the engine between a taxi-in and a following taxi-out. <EOS>