# US 2019/0316484 A1 · Anti-windmilling system for a gas turbine engine > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2019/0316484 A1 - Document ID: US20190316484A1 - Status: Published application - Kind: A1 - Application number: 16/424,641 - Filed: 2019-05-29 - Published: 2019-10-17 - Earliest claimed: 2016-04-27 - Assignees: United Technologies Corporation - Applicants: United Technologies Corporation - Inventors: Gary D. Roberge - Web page: https://patentgrep.com/patent/US20190316484A1 ## CPC - F01D 21/006: {Arrangements of brakes (brakes per se F16D)} - F01D 15/12: Combinations with mechanical gearing (driven by multiple engines F01D13/00) - F02C 7/32: Arrangement, mounting, or driving, of auxiliaries - F02C 7/36: Power transmission arrangements between the different shafts of the gas turbine plant, or between the gas-turbine plant and the power user ({F02C3/107 - F02C3/13 and} F02C7/32 take precedence; couplings for transmitting rotation F16D; gearing in general F16H) - F02K 3/06: with front fan - F04D 29/053: Shafts - F04D 29/325: {for axial flow fans (blade mountings F04D29/34, blades F04D29/38)} - F16D 63/002: {Brakes with direct electrical or electro-magnetic actuation} - F16D 63/006: {Positive locking brakes} - F01D 21/04: responsive to undesired position of rotor relative to stator {or to breaking-off of a part of the rotor}, e.g. indicating such position - F05D 2220/32: in gas turbines - F05D 2220/323: for aircraft propulsion, e.g. jet engines - F05D 2260/40311: of the epicyclical, planetary or differential type - F05D 2260/902: using frictional mechanical forces - F05D 2260/903: using electrical or magnetic forces - F05D 2270/62: Electrical actuators - F16D 11/16: with clutching members movable otherwise than only axially (F16D11/02, F16D11/08 take precedence) - F16D 2011/006: {Locking or detent means, i.e. means to keep the clutch in engaged condition} - F01D: NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES (machines or engines for liquids F03; non-positive displacement pumps F04D) - F02C: GAS-TURBINE PLANTS; AIR INTAKES FOR JET-PROPULSION PLANTS; CONTROLLING FUEL SUPPLY IN AIR-BREATHING JET-PROPULSION PLANTS (construction of turbines F01D; jet-propulsion plants F02K; construction of compressors or fans F04; generating combustion products of high pressure or high velocity F23R; using gas turbines in compression refrigeration plants F25B11/00) - F02K: JET-PROPULSION PLANTS (features of jet-propulsion plants common to gas-turbine plants, air intakes or fuel supply control of air-breathing jet-propulsion plants F02C7/00, F02C9/00) - F04D: NON-POSITIVE-DISPLACEMENT PUMPS (engine fuel-injection pumps F02M; ion pumps H01J41/12; electrodynamic pumps H02K44/02) - F16D: COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES - F05D: INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS ## Abstract A gas turbine engine has an engine static structure and at least one component rotatable relative to the engine static structure about an engine axis of rotation. A fan is coupled to at least one component for rotation about the engine axis of rotation. An actuator is mounted to the engine static structure, wherein the actuator is activated to prevent the fan from rotation and is inactivated to allow the fan to rotate. A method for preventing rotation of a fan in a gas turbine engine is also disclosed. ## Claims ### Claim 1 A gas turbine engine comprising: an engine static structure; at least one shaft that is driven by a turbine section and is rotatable relative to the engine static structure about an engine axis of rotation; a fan that is driven via a gear system by the at least one shaft for rotation about the engine axis of rotation; one or more sensors used to identify a non-operational engine condition that comprises at least a windmilling condition; a control that receives data from the one or more sensors to determine if an aircraft is on ground and is experiencing the windmilling condition by determining weight on wheels, determining if engine shut-down has been completed, and/or determining aircraft velocity to identify if the gas turbine engine is stationary; and an actuator mounted to the engine static structure aft of the turbine section, wherein the actuator is activated by the control to prevent rotation of the fan during the windmilling condition. ### Claim 2 (depends on 1) The gas turbine engine of claim 1, wherein the actuator comprises a solenoid. ### Claim 3 (depends on 1) The gas turbine engine of claim 1, wherein the actuator is activated by the control to prevent rotation of the fan by preventing rotation of the at least one shaft. ### Claim 4 (depends on 3) The gas turbine engine of claim 3, wherein the actuator includes a first feature and the at least one shaft includes a second feature that selectively locks with the first feature when the actuator is activated by the control to prevent rotation of the at least one shaft. ### Claim 5 (depends on 4) The gas turbine engine of claim 4, wherein the second feature comprises a magnetic material that is attached to the at least one shaft and the first feature interacts with the magnetic material to prevent rotation of the at least one shaft when activated. ### Claim 6 (depends on 4) The gas turbine engine of claim 4, wherein the first and second features interact using friction to prevent the at least one shaft from rotating. ### Claim 7 (depends on 1) The gas turbine engine of claim 1, wherein the control inactivates the actuator when the gas turbine engine returns to an operational engine condition. ### Claim 8 (depends on 7) The gas turbine engine of claim 7, wherein the windmilling condition occurs when the gas turbine engine is powered off, and wherein the operational engine condition occurs when the gas turbine engine is powered on. ### Claim 9 (depends on 1) The gas turbine engine of claim 1, wherein the one or more sensors comprises at least one of a weight on wheels sensor, shaft speed sensor, fan speed sensor, aircraft velocity sensor, engine fuel flow sensor, engine pressure sensor, or an engine temperature sensor. ### Claim 10 (depends on 1) The gas turbine engine of claim 1, wherein the one or more sensors comprises at least a weight sensor, speed sensor, and an engine condition sensor. ### Claim 11 (depends on 10) The gas turbine engine of claim 10, wherein the engine condition sensor senses at least one of engine fuel flow, pressure, or temperature. ### Claim 12 A gas turbine engine comprising: an engine static structure; at least one shaft rotatable relative to the engine static structure about an engine axis of rotation; a turbine section configured to drive the at least one shaft; a fan coupled to the at least one shaft via a geared architecture; at least one sensor used to identify an engine non-operational engine condition that comprises at least a windmilling condition; a control that receives data from the at least one sensor to determine if an aircraft is on ground and is experiencing the windmilling condition by determining weight on wheels, determining if engine shut-down has been completed, and/or determining aircraft velocity to identify if the gas turbine engine is stationary; and an actuator mounted to the engine static structure aft of the turbine section, wherein the actuator includes a first feature and the at least one shaft includes a second feature that selectively locks with the first feature when the actuator is activated by the control to prevent rotation of the at least one shaft during the windmilling condition. ### Claim 13 (depends on 12) The gas turbine engine of claim 12, wherein the actuator comprises a solenoid. ### Claim 14 (depends on 12) The gas turbine engine of claim 12, wherein the actuator is activated by the control to prevent rotation of the fan during the windmilling condition and is inactivated to allow the fan to rotate during an engine operational condition. ### Claim 15 (depends on 12) The gas turbine engine of claim 12, wherein the at least one sensor comprises at least one of a weight on wheels sensor, shaft speed sensor, fan speed sensor, aircraft velocity sensor, engine fuel flow sensor, engine pressure sensor, or an engine temperature sensor. ### Claim 16 (depends on 12) The gas turbine engine of claim 12, wherein the at least one sensor comprises at least a weight sensor, speed sensor, and an engine condition sensor. ### Claim 17 (depends on 12) The gas turbine engine of claim 12, wherein one of the first and second features comprises a dog extension and wherein the other of the first and second features comprises a recess that receives the dog extension to prevent rotation of the at least one shaft. ### Claim 18 (depends on 12) The gas turbine engine of claim 12, wherein the second feature comprises a magnetic material that is attached to the at least one shaft and the first feature interacts with the magnetic material to prevent rotation of the at least one shaft when activated by the control. ### Claim 19 (depends on 12) The gas turbine engine of claim 12, wherein the control activates the actuator to frictionally and/or magnetically restrain the at least one shaft from rotating to prevent the fan from windmilling.