IMPROVING ACCELERATION OF A GAS TURBINE

A gas turbine engine (101) for an aircraft comprises a high-pressure (HP) spool comprising an HP compressor (105) and a first electric machine (117) driven by an HP turbine (107); a low-pressure (LP) spool comprising an LP compressor (104) and a second electric machine (119) driven by an LP turbine (108); a combustion system (106) comprising a fuel metering unit; and an engine controller (123) configured to, in response to a change of a throttle lever angle setting indicative of an acceleration event, increase fuel flow to the combustion system (106) by the fuel metering unit, and to operate the first electric machine (117) in a motor mode to increase the HP spool rotational speed and engine core mass flow.