Gas turbine engine and method to cool a gas turbine engine case assembly

1. A method of cooling a gas turbine engine case assembly, comprising:

calculating an open position of a fan air valve being operatively connected to a precooler having a bypass inlet configured to receive bypass air that bypasses a gas turbine engine core to facilitate a provision of bypass air through a fan air valve inlet to the bypass inlet to a first open position, responsive to a pressure regulating/shut-off valve being in a closed position to inhibit a fluid flow through a bleed air inlet of the precooler;

monitoring a core compartment temperature of a core compartment with a temperature sensor positioned within the core compartment;

when the pressure regulating/shut-off valve is in the closed position and the core compartment temperature is greater than a target core compartment temperature, moving the fan air valve to the first position, and

when the fan air valve is in the first open position, bleeding the bypass air through a bypass outlet of the precooler into the core compartment to impinge on the gas turbine engine case assembly proximate a turbine section of the core compartment, thereby cooling the core compartment and the gas turbine engine case assembly.

2. The method of claim 1 , further comprising moving the fan air valve to a closed position to inhibit the provision of bypass air through the fan air valve inlet to the bypass inlet, in response to the core compartment temperature satisfying the target core compartment temperature.

3. The method of claim 1 , further comprising moving the fan air valve to a second open position to facilitate the provision of bypass air through the fan air valve inlet to the bypass inlet, in response to the pressure regulating/shut-off valve being in an open position, a bleed air conduit having the pressure regulating/shut-off valve operatively connected to the bleed air inlet of the precooler and a compressor section of the gas turbine engine core.

4. The method of claim 3 , wherein the second open position of the fan air valve is based on a temperature of bleed air supplied through the bleed air conduit.

5. The method of claim 1 , wherein the target core compartment temperature is based on at least one of a gas turbine engine rotational speed, an altitude, an aircraft mach number, and an ambient air temperature.

6. The method of claim 5 , wherein the gas turbine engine rotational speed is based on a rotational speed of at least one of a low pressure shaft and a high pressure shaft.

7. A method of cooling a gas turbine engine case assembly, comprising:

estimating a core compartment temperature based on at least one of a gas turbine engine rotational speed and an ambient air temperature;

calculating a target core compartment temperature of a core compartment;

comparing the estimated core compartment temperature to the target core compartment temperature, in response to a pressure regulating/shut-off valve operatively connected to a bleed air inlet of a precooler being in a closed position;

calculating a fan air valve position of a fan air valve operatively connected to the precooler based on the target core compartment temperature, in response to the estimated core compartment temperature being greater than the target core compartment temperature;

moving the fan air valve to the calculated fan air valve position; and

when the fan air valve is in the calculated fan air valve position, bleeding bypass air from the precooler into the core compartment, to impinge on the gas turbine engine case assembly proximate a turbine section of the core compartment, thereby cooling the core compartment and the gas turbine engine case assembly, at least until the estimated core compartment temperature satisfies the target core compartment temperature.

8. The method of claim 7 , further comprising:

closing the fan air valve in response to the estimated core compartment temperature becoming less than the target core compartment temperature.