Method and system for operating a gas turbine engine

A system for operating a gas turbine engine, the system comprising:

• a processor unit;
• and
• a non-transitory computer-readable memory communicatively coupled to the processing unit and comprising computer-readable program instructions executable by the processing unit for:
• receiving a signal of at least one parameter indicative of a fuel-to-air ratio in a combustor being below a predetermined value;
• and
• in response to receiving the signal:
• generating a command causing compressed air to bleed from a compressed air source feeding the combustor to increase the fuel-to-air ratio within the combustor to at least the predetermined value.

A system for operating a gas turbine engine, the system comprising:

• a combustor having an outer liner;
• a plenum surrounding the combustor and defined between a gas generator case and the outer liner;
• a transfer tube having an inlet fluidly connected to the plenum and at least two outlets, a first flow passageway defined between the inlet and a first outlet of the at least two outlets, the first flow passageway configured to supply compressed air from the plenum to external systems, a second flow passageway defined between the inlet and a second outlet of the at least two outlets, the second flow passageway connected to a discharge region outside of the plenum;
• a flow valve disposed within the second flow passageway and operable between an open position and a closed position, in the open position the flow valve is adapted to fluidly connect the plenum with the discharge region and in the closed position the flow valve is adapted to block the second flow passageway between the plenum and the discharge region;
• and
• a controller communicatively coupled to the flow valve to control operation thereof by:
• causing the flow valve to open for a time period;
• and
• subsequent to the time period, causing the fuel flow valve to close.