Method of operating a lubrication system for a turbine engine

1 . A method of operating a lubrication system for a turbine engine that includes a fan, a hydraulic system containing a hydraulic fluid, a fuel system containing a fuel, and one or more rotating components that receive a lubricant from the lubrication system, the lubrication system including one or more tanks that store the lubricant, a primary lubrication system, and an auxiliary lubrication system, and the hydraulic system including one or more hydraulic fluid reservoirs containing the hydraulic fluid and one or more hydraulic lines to supply the hydraulic fluid to one or more hydraulic control systems, the method comprising:

supplying the lubricant from the one or more tanks to the one or more rotating components via the primary lubrication system during a normal operation of the turbine engine;

detecting at least one of a fuel pressure of the fuel in the fuel system or a hydraulic pressure of the hydraulic fluid being supplied from the one or more hydraulic fluid reservoirs through the one or more hydraulic lines to the one or more hydraulic control systems;

determining whether the at least one of the fuel pressure is less than a fuel pressure threshold or the hydraulic pressure is less than a hydraulic pressure threshold; and

activating the auxiliary lubrication system to supply the lubricant to the one or more rotating components from the auxiliary lubrication system when the at least one of the fuel pressure is less than the fuel pressure threshold or the hydraulic pressure is less than the hydraulic pressure threshold.

2 . The method of claim 1 , further comprising supplying the lubricant to the one or more rotating components from the primary lubrication system if the fuel pressure is greater than or equal to the fuel pressure threshold and the hydraulic pressure is greater than or equal to the hydraulic pressure threshold.

3 . The method of claim 1 , wherein the auxiliary lubrication system comprises one or more drain valves and a secondary reservoir, and activating the auxiliary lubrication system includes closing the one or more drain valves to fill the secondary reservoir with the lubricant.

4 . The method of claim 1 , wherein the turbine engine further comprises a controller, and activating the auxiliary lubrication system includes controlling the auxiliary lubrication system with the controller to activate the auxiliary lubrication system.

5 . The method of claim 1 , wherein activating the auxiliary lubrication system includes passively controlling the auxiliary lubrication system based on the fuel pressure or the hydraulic pressure to activate the auxiliary lubrication system.

6 . The method of claim 1 , further comprising inactivating the auxiliary lubrication system if the fuel pressure is greater than or equal to the fuel pressure threshold and the hydraulic pressure is greater than or equal to the hydraulic pressure threshold.

7 . The method of claim 1 , further comprising shutting down the turbine engine, and activating the auxiliary lubrication system to supply the lubricant to the one or more rotating components from the auxiliary lubrication system when the turbine engine is shut down.

8 . The method of claim 1 , further comprising powering the auxiliary lubrication system by rotation of the fan.

9 . The method of claim 1 , wherein the turbine engine further includes a turbo-engine, and the method further comprises determining a rotational speed of the turbo-engine.

10 . The method of claim 9 , further comprising determining whether the rotational speed of the turbo-engine is less than a turbo-engine rotational speed threshold, and activating the auxiliary lubrication system to supply the lubricant to the one or more rotating components from the auxiliary lubrication system when the rotational speed of the turbo-engine is less than the turbo-engine rotational speed threshold.

11 . The method of claim 1 , wherein the auxiliary lubrication system comprises an auxiliary pump that is drivingly coupled to the fan, and activating the auxiliary lubrication system includes powering the auxiliary pump to pump the lubricant to the one or more rotating components from the auxiliary lubrication system.

12 . The method of claim 11 , wherein the auxiliary lubrication system comprises a clutch that engages or disengages the auxiliary pump, and activating the auxiliary lubrication system includes engaging the clutch to power the auxiliary pump by rotation of the fan.

13 . The method of claim 1 , wherein powering the auxiliary lubrication system by rotation of the fan includes powering the auxiliary lubrication system in a first rotational direction of the fan, and powering the auxiliary lubrication system in a second rotational direction of the fan.

14 . The method of claim 13 , wherein the second rotational direction is opposite the first rotational direction.

15 . The method of claim 1 , further comprising determining a lubricant flow in the primary lubrication system based on at least one of the fuel pressure or the hydraulic pressure.

16 . The method of claim 15 , further comprising determining the lubricant flow based on a lubricant pressure of the lubricant in the primary lubrication system.

17 . The method of claim 16 , wherein the lubrication system further comprises a pressure signal line, and determining the lubricant pressure of the lubricant in the primary lubrication system includes receiving an indication of the lubricant pressure of the lubricant in the primary lubrication system from the pressure signal line.

18 . The method of claim 16 , wherein the turbine engine further comprises one or more pressure sensors, and determining the at least one of the lubricant pressure of the lubricant in the primary lubrication system, the fuel pressure in the turbine engine, or the hydraulic pressure in the turbine engine includes receiving an indication of the lubricant pressure, the fuel pressure, or the hydraulic pressure from the one or more pressure sensors.

19 . The method of claim 16 , further comprising determining whether the lubricant pressure of the lubricant in the primary lubrication system is less than a primary pressure threshold, and activating the auxiliary lubrication system to supply the lubricant to the one or more rotating components from the auxiliary lubrication system when the lubricant pressure of the lubricant in the primary lubrication system is less than the primary pressure threshold.

20 . A turbine engine for an aircraft, the turbine engine comprising:

a fan having a fan shaft, the fan generating compressed air during a normal operation of the turbine engine;

a hydraulic system including one or more hydraulic fluid reservoirs for storing a hydraulic fluid, one or more hydraulic lines in fluid communication with the one or more hydraulic fluid reservoirs, and one or more hydraulic control systems, the hydraulic system being configured to provide the hydraulic fluid from the one or more hydraulic fluid reservoirs to the one or more hydraulic control systems to actuate one or more components in the turbine engine;

a fuel system containing a fuel, the fuel system being configured to provide a flow of the fuel; and

a lubrication system configured to provide a lubricant to one or more rotating components within the turbine engine, the lubrication system comprising:

one or more tanks to store the lubricant;

a primary lubrication system that supplies lubricant to the one or more rotating components from the one or more tanks during the normal operation of the turbine engine; and

an auxiliary lubrication system comprising an auxiliary pump and a clutch, and the auxiliary pump being drivingly coupled to the fan shaft when the clutch is in an engaged state,

wherein the clutch is in the engaged state when at least one of a detected fuel pressure of the fuel in the fuel system is less than a fuel pressure threshold or a detected hydraulic pressure of the hydraulic fluid in the hydraulic system is less than a hydraulic pressure threshold.