Abstract: An apparatus has: a first member; a shaft rotatable relative to the first member about an axis; and a seal system. The seal system has a seal carrier having: an axially-extending wall having an inner diameter (ID) surface; and a radially-extending wall having a first surface. A seal is carried by the first member and has: an outer diameter (OD) surface; and a seal face. A seat is carried by the shaft and has a seat face in sliding sealing engagement with the seal face. One or more springs bias the seal carrier relative to the first member so as to bias the seal face against the seat face. At least one of the seal carrier inner diameter (ID) surface and seal outer diameter (OD) surface is formed by a coating.

Abstract: A method for controlling a gas turbine engine includes receiving, by a signal processor from a sensor, an operating condition of the gas turbine engine and determining, by the signal processor, whether the operating condition is within an acceptable threshold. In response to the operating condition being outside the acceptable threshold, the method includes restricting, by the signal processor, a subsequent engine restart of the gas turbine engine. Restricting the subsequent engine restart of the gas turbine engine may comprise preventing the subsequent restart. In various embodiments, restricting the subsequent engine restart of the gas turbine engine comprises limiting a subsequent operating state of the gas turbine engine after the subsequent restart.

Abstract: A lubrication system may comprise a shaft including a shaft gear, a pump configured to supply a flow of lubricant to a component benefiting from lubrication and an input gear train coupled to the shaft gear and configured to drive the gear pump with a unidirectional rotation in response to a forward rotation and an reverse rotation of the shaft gear. The input gear grain may comprise a primary gear coupled to a common shaft. The input gear train may further comprise a forward shaft and a forward gear about the common shaft, wherein the forward gear is coupled to the forward shaft.

Abstract: A gas turbine engine includes, among other things, a bearing compartment, a shaft configured to rotate during operation of the gas turbine engine, and a sleeve configured to rotate with the shaft during operation of the gas turbine engine. The sleeve includes a variable radial dimension about a circumference of the sleeve. The engine further includes a seal statically mounted relative to the sleeve and configured to cooperate with the sleeve to seal the bearing compartment.

Abstract: A gas turbine engine includes, among other things, a bearing compartment, a shaft configured to rotate during operation of the gas turbine engine, and a sleeve configured to rotate with the shaft during operation of the gas turbine engine. The sleeve includes a variable radial dimension about a circumference of the sleeve. The engine further includes a seal statically mounted relative to the sleeve and configured to cooperate with the sleeve to seal the bearing compartment.

Abstract: A gas turbine engine includes, among other things, a bearing compartment, a shaft configured to rotate during operation of the gas turbine engine, and a sleeve configured to rotate with the shaft during operation of the gas turbine engine. The sleeve includes a variable radial dimension about a circumference of the sleeve. The engine further includes a seal statically mounted relative to the sleeve and configured to cooperate with the sleeve to seal the bearing compartment.

Abstract: A method for controlling a gas turbine engine includes receiving, by a signal processor from a sensor, an operating condition of the gas turbine engine and determining, by the signal processor, whether the operating condition is within an acceptable threshold. In response to the operating condition being outside the acceptable threshold, the method includes restricting, by the signal processor, a subsequent engine restart of the gas turbine engine. Restricting the subsequent engine restart of the gas turbine engine may comprise preventing the subsequent restart. In various embodiments, restricting the subsequent engine restart of the gas turbine engine comprises limiting a subsequent operating state of the gas turbine engine after the subsequent restart.

Abstract: A lubrication system may comprise a shaft including a shaft gear, a pump configured to supply a flow of lubricant to a component benefiting from lubrication and an input gear train coupled to the shaft gear and configured to drive the gear pump with a unidirectional rotation in response to a forward rotation and an reverse rotation of the shaft gear. The input gear grain may comprise a primary gear coupled to a common shaft. The input gear train may further comprise a forward shaft and a forward gear about the common shaft, wherein the forward gear is coupled to the forward shaft.

Abstract: A gas turbine engine includes a fan and a first drive shaft connected to the fan. A fan drive gear box connects the first drive shaft to a second drive shaft and is configured to allow the first drive shaft to rotate at a different speed than the second drive shaft. The gas turbine engine also includes a sprag clutch disposed circumferentially around the first shaft and connected to the first drive shaft. The sprag clutch is configured to allow rotation of the first drive shaft and the fan in a first direction while prohibiting rotation of the fan and the first drive shaft in a second direction.

Abstract: According to one aspect of the present disclosure, a lubrication monitoring system is disclosed that includes a fan, a gear reduction operatively coupled to the fan, and a lubrication pump that is operatively coupled to the fan and is in fluid communication with the gear reduction. A first sensor is configured to detect a windmilling condition of the fan, and a second sensor is configured to detect an operational state of the lubrication pump. A controller in communication with the first and second sensors is configured to monitor the windmilling condition and the operational state of the lubrication pump, and command a status indicator in response thereto.

Abstract: A lubrication system includes a shaft rotatable about an axis, a lubrication pump configured to supply a lubricant flow to a gear system, and a gear train coupled to the shaft and configured to drive the lubrication pump in a first direction responsive to rotation of the shaft in both the first direction and a second direction. A gas turbine engine and method are also disclosed.

Abstract: What is described is a system for pumping lubricant to a component of a gas turbine engine. The system includes a fan gear coupled to a fan shaft of the gas turbine engine and configured to rotate in a forward direction and in a reverse direction based at least partially on a direction of wind relative to a fan of the gas turbine engine. The system also includes a first pump coupled to the fan gear and configured to pump lubricant to the component in response to the fan rotating in the forward direction. The system also includes a second pump coupled to the fan gear and configured to pump lubricant to the component in response to the fan rotating in the reverse direction.

Abstract: A disclosed lubrication system for turbofan engine includes a primary lubricant circuit, a primary pump driving lubricant through the primary circuit, an auxiliary lubricant circuit in communication with the primary lubricant circuit and an auxiliary lubricant pump driving lubricant through the auxiliary lubricant circuit. A first valve downstream of an outlet of auxiliary lubricant pump separates the auxiliary lubricant circuit from the primary lubricant circuit. A sensor is disposed within the auxiliary lubricant circuit for sensing pressure within the auxiliary lubricant circuit separate from a pressure within the primary lubricant circuit.

Abstract: A gas turbine engine includes a fan and a first drive shaft connected to the fan. A fan drive gear box connects the first drive shaft to a second drive shaft and is configured to allow the first drive shaft to rotate at a different speed than the second drive shaft. The gas turbine engine also includes a sprag clutch disposed circumferentially around the first shaft and connected to the first drive shaft. The sprag clutch is configured to allow rotation of the first drive shaft and the fan in a first direction while prohibiting rotation of the fan and the first drive shaft in a second direction.

Abstract: What is described is a system for pumping lubricant to a component of a gas turbine engine. The system includes a fan gear coupled to a fan shaft of the gas turbine engine and configured to rotate in a forward direction and in a reverse direction based at least partially on a direction of wind relative to a fan of the gas turbine engine. The system also includes a first pump coupled to the fan gear and configured to pump lubricant to the component in response to the fan rotating in the forward direction. The system also includes a second pump coupled to the fan gear and configured to pump lubricant to the component in response to the fan rotating in the reverse direction.

Abstract: According to one aspect of the present disclosure, a lubrication monitoring system is disclosed that includes a fan, a gear reduction operatively coupled to the fan, and a lubrication pump that is operatively coupled to the fan and is in fluid communication with the gear reduction. A first sensor is configured to detect a windmilling condition of the fan, and a second sensor is configured to detect an operational state of the lubrication pump. A controller in communication with the first and second sensors is configured to monitor the windmilling condition and the operational state of the lubrication pump, and command a status indicator in response thereto.

Abstract: Monitoring a thickness of a lubricant film in a journal bearing of an epicyclic gear system in an operating gas turbine engine is provided. The method comprises receiving, by a signal processor from a sensor, an electrical property measurement across the lubricant film. The electrical property measurement is converted by the signal processor into a calculated lubricant film thickness measurement. Whether the calculated lubricant film thickness measurement is below a predetermined minimum lubricant film thickness is determined by the signal processor. An alert is outputted if the calculated lubricant film thickness measurement is below the predetermined minimum lubricant film thickness.

Abstract: A lubrication system includes a shaft rotatable about an axis, a lubrication pump configured to supply a lubricant flow to a gear system, and a gear train coupled to the shaft and configured to drive the lubrication pump in a first direction responsive to rotation of the shaft in both the first direction and a second direction. A gas turbine engine and method are also disclosed.

Abstract: A disclosed lubrication system for turbofan engine includes a primary lubricant circuit, a primary pump driving lubricant through the primary circuit, an auxiliary lubricant circuit in communication with the primary lubricant circuit and an auxiliary lubricant pump driving lubricant through the auxiliary lubricant circuit. A first valve downstream of an outlet of auxiliary lubricant pump separates the auxiliary lubricant circuit from the primary lubricant circuit. A sensor is disposed within the auxiliary lubricant circuit for sensing pressure within the auxiliary lubricant circuit separate from a pressure within the primary lubricant circuit.

Abstract: A lubrication system for a fan drive gear system includes a lubricant supply and a collection conduit for drawing lubricant from within the lubricant supply. The collection conduit includes a first opening and a second opening for withdrawing lubricant and supplying lubricant to a pump. During normal operation lubricant may be drawn through both first and second openings. During negative G operating conditions a fitting at the second opening blocks the second opening to prevent air from being drawn into the lubricant system and communicated to the pump.