A system, comprising: a gas turbine engine, comprising: a compressor; a combustor; and a turbine; an intercooler configured to receive a discharge air from the compressor and to cool the discharge air; and a first conduit configured to divert a portion of the cooled discharge air from the intercooler or a location downstream of the intercooler forming a first air source to a bearing located within the turbine to pressurize the bearing to block leakage of fluid from the bearing, a second air source, a second conduit coupled to the second air source configured to receive air from the second air source and to provide the air to the bearing to pressurize the bearing and a controller, characterised in that a first air valve is disposed along the first conduit, and the controller coupled to the first air valve, wherein the controller is configured to control actuation of the first air valve to regulate an amount of the cooled discharge air provided to the bearing, a second air valve is disposed along the second conduit and the controller is configured to control actuation of the second air valve to regulate an amount of the air provided to the bearing, the controller, during startup and/or shutdown of the gas turbine engine, is configured to control actuation of the first and second air valves (76, 88) to block the cooled discharge air from being provided to the bearing and to enable air from the secondary source to be provided to the bearing, the controller, during steady state operation of the gas turbine engine, is configured to control actuation of the first and second air valves (76, 88) to block air from the secondary source from being provided to the bearing and to enable the cooled discharge air to be provided to the bearing. a compressor; a combustor; and a turbine; an intercooler configured to receive a discharge air from the compressor and to cool the discharge air; and a first conduit configured to divert a portion of the cooled discharge air from the intercooler or a location downstream of the intercooler forming a first air source to a bearing located within the turbine to pressurize the bearing to block leakage of fluid from the bearing, a second air source, a second conduit coupled to the second air source configured to receive air from the second air source and to provide the air to the bearing to pressurize the bearing and a controller, characterised in that a first air valve is disposed along the first conduit, and the controller coupled to the first air valve, wherein the controller is configured to control actuation of the first air valve to regulate an amount of the cooled discharge air provided to the bearing, a second air valve is disposed along the second conduit and the controller is configured to control actuation of the second air valve to regulate an amount of the air provided to the bearing, the controller, during startup and/or shutdown of the gas turbine engine, is configured to control actuation of the first and second air valves (76, 88) to block the cooled discharge air from being provided to the bearing and to enable air from the secondary source to be provided to the bearing, the controller, during steady state operation of the gas turbine engine, is configured to control actuation of the first and second air valves (76, 88) to block air from the secondary source from being provided to the bearing and to enable the cooled discharge air to be provided to the bearing.