Abstract: A monitoring system for a dual-stage, separated gas/fluid shock strut may comprise a controller and a tangible, non-transitory memory configured to communicate with the controller. The tangible, non-transitory memory may have instructions stored thereon that, in response to execution by the controller, cause the controller to perform various operations. Said operations may include calculating, by the controller, a secondary chamber nominal pressure, determining, by the controller, a shock strut stroke associated with the secondary chamber nominal pressure, calculating, by the controller, a volume of oil in an oil chamber of the shock strut, calculating, by the controller, a volume of gas in a primary chamber of the shock strut, calculating, by the controller, a secondary chamber inflation pressure, and calculating, by the controller, a volume of oil leaked into the primary chamber of the shock strut.

Abstract: A monitoring system for a dual-stage, pressure-activated, mixed fluid gas shock strut, may comprise a controller, and a tangible, non-transitory memory configured to communicate with the controller, the tangible, non-transitory memory having instructions stored thereon that, in response to execution by the controller, cause the controller to perform operations comprising receiving, by the controller, a primary chamber temperature sensor reading, receiving, by the controller, a primary chamber pressure sensor reading, receiving, by the controller, a shock strut stroke sensor reading, and calculating, by the controller, an oil volume in a primary chamber of the shock strut. The instructions may cause the controller to perform further operations comprising calculating, by the controller, a number of moles of gas in a primary chamber of the shock strut and calculating, by the controller, a number of moles of gas in a secondary chamber of the shock strut.

Abstract: A monitoring system for a dual-stage, stroke activated, mixed fluid gas shock strut may comprise a controller, and a tangible, non-transitory memory configured to communicate with the controller. The tangible, non-transitory memory may have instructions stored thereon that, in response to execution by the controller, cause the controller to perform various operations. Said operations may include calculating, by the controller, a compression factor, determining, by the controller, a plurality of compression factors for known oil volumes based on at least one of the primary chamber temperature sensor reading and the shock strut stroke sensor reading, and calculating, by the controller, an oil volume in a primary chamber of the shock strut.

Abstract: A monitoring system for a dual-stage, separated gas/fluid shock strut may comprise a controller and a tangible, non-transitory memory configured to communicate with the controller. The tangible, non-transitory memory may have instructions stored thereon that, in response to execution by the controller, cause the controller to perform various operations. Said operations may include determining, by the controller, a shock strut stroke at which a secondary chamber of the shock strut is activated, calculating, by the controller, a volume of oil in an oil chamber of the shock strut, calculating, by the controller, a volume of gas in a primary chamber of the shock strut, and calculating, by the controller, a volume of oil leaked into the primary chamber of the shock strut.

Abstract: A monitoring system for a dual-stage, separated gas/fluid shock strut may comprise a controller and a tangible, non-transitory memory configured to communicate with the controller. The tangible, non-transitory memory may have instructions stored thereon that, in response to execution by the controller, cause the controller to perform various operations. Said operations may include calculating, by the controller, a secondary chamber nominal pressure, determining, by the controller, a shock strut stroke associated with the secondary chamber nominal pressure, calculating, by the controller, a volume of oil in an oil chamber of the shock strut, calculating, by the controller, a volume of gas in a primary chamber of the shock strut, calculating, by the controller, a secondary chamber inflation pressure, and calculating, by the controller, a volume of oil leaked into the primary chamber of the shock strut.

Abstract: A method for servicing a dual-stage, separated gas/fluid shock strut may comprise measuring a servicing temperature, charging a secondary gas chamber with compressed gas, wherein a secondary chamber pressure corresponds to the servicing temperature, pumping oil into the shock strut, and charging a primary gas chamber with compressed gas.

Abstract: A method includes detecting at least one position measurement of a separator piston of a pitch trim actuator. The method includes detecting at least one pressure measurement of an oil. The method includes detecting at least one temperature measurement of the oil. The method includes storing at least one position value based on the at least one position measurement of the separator piston, at least one pressure value based on the at least one pressure measurement of the oil and at least one temperature value based on the at least one temperature measurement of the oil. The method includes determining whether the pitch trim actuator requires servicing based on the at least one position value, the at least one pressure value, and the at least one temperature value.

Abstract: A hard-landing detection system includes a wheel assembly, a shock strut mechanically coupled to the wheel assembly and to landing gear structure of the landing gear assembly, a controller having a processor, and a tangible, non-transitory memory configured to communicate with the processor. The tangible, non-transitory memory has instructions stored thereon that, in response to execution by the processor, cause the hard-landing detection system to perform operations that include detecting, by the processor, a landing event and determining, by the processor, whether the landing event is hard. The hard-landing system may further include a stroke position sensor and detecting the landing event may include using the stroke position sensor to measure a stroke profile of the shock strut. Further, determining whether the landing event is hard may include comparing, by the processor, the stroke profile of the shock strut to a predetermined maximum shock strut stroke.

Abstract: System and methods for servicing and monitoring shock struts are provided. A shock strut servicing assistance system may comprise: a controller in electronic communication with a display; and a tangible, non-transitory memory configured to communicate with the controller, the tangible, non-transitory memory having instructions stored thereon that, in response to execution by the controller, cause the controller to perform operations comprising: calculating, by the controller, a dead volume of a shock strut and determining, by the controller, a first decision, the first decision being whether or not the dead volume of the shock strut is negative. A shock strut servicing assistance system may be for servicing a shock strut having a negative dead volume.

Abstract: Methods for servicing shock struts are provided. In various embodiments, a method for servicing a shock strut may comprise deflating the shock strut; compressing the shock strut until the shock strut is in a fully compressed position; and charging the shock strut with a liquid until a pressure of the liquid decreases a volume of a residual air located inside of the shock strut. In various embodiments, charging the shock strut with liquid under pressure may reduce the volume of trapped air inside of the shock strut to a negligible volume, eliminating the servicing variations.

Abstract: A monitoring system for a dual-stage, pressure-activated, mixed fluid gas shock strut, may comprise a controller, and a tangible, non-transitory memory configured to communicate with the controller, the tangible, non-transitory memory having instructions stored thereon that, in response to execution by the controller, cause the controller to perform operations comprising receiving, by the controller, a primary chamber temperature sensor reading, receiving, by the controller, a primary chamber pressure sensor reading, receiving, by the controller, a shock strut stroke sensor reading, and calculating, by the controller, an oil volume in a primary chamber of the shock strut. The instructions may cause the controller to perform further operations comprising calculating, by the controller, a number of moles of gas in a primary chamber of the shock strut and calculating, by the controller, a number of moles of gas in a secondary chamber of the shock strut.

Abstract: A hard-landing detection system includes a wheel assembly, a shock strut mechanically coupled to the wheel assembly and to landing gear structure of the landing gear assembly, a controller having a processor, and a tangible, non-transitory memory configured to communicate with the processor. The tangible, non-transitory memory has instructions stored thereon that, in response to execution by the processor, cause the hard-landing detection system to perform operations that include detecting, by the processor, a landing event and determining, by the processor, whether the landing event is hard. The hard-landing system may further include a stroke position sensor and detecting the landing event may include using the stroke position sensor to measure a stroke profile of the shock strut. Further, determining whether the landing event is hard may include comparing, by the processor, the stroke profile of the shock strut to a predetermined maximum shock strut stroke.

Abstract: Methods for servicing shock struts are provided. In various embodiments, a method for servicing a shock strut may comprise deflating the shock strut; compressing the shock strut until the shock strut is in a fully compressed position; and charging the shock strut with a liquid until a pressure of the liquid decreases a volume of a residual air located inside of the shock strut. In various embodiments, charging the shock strut with liquid under pressure may reduce the volume of trapped air inside of the shock strut to a negligible volume, eliminating the servicing variations.

Abstract: System and methods for servicing and monitoring shock struts are provided. A shock strut servicing assistance system may comprise: a controller in electronic communication with a display; and a tangible, non-transitory memory configured to communicate with the controller, the tangible, non-transitory memory having instructions stored thereon that, in response to execution by the controller, cause the controller to perform operations comprising: calculating, by the controller, a dead volume of a shock strut and determining, by the controller, a first decision, the first decision being whether or not the dead volume of the shock strut is negative. A shock strut servicing assistance system may be for servicing a shock strut having a negative dead volume.

Abstract: A shock strut servicing assistance system may comprise a controller including a display, and a tangible, non-transitory memory configured to communicate with the controller. The tangible, non-transitory memory may have instructions stored thereon that, in response to execution by the controller, cause the controller to perform operations comprising calculating, by the controller, a first fluid level, generating, by the controller, a first datum corresponding to the first fluid level, receiving, by the shock strut, a fluid in response to the first datum, calculating, by the controller, a second fluid level, generating, by the controller, a second datum, and storing, by the controller, a final fluid level.

Abstract: System and methods for servicing and monitoring shock struts are provided. A method for servicing a shock strut may include calculating a first fluid level; generating a first datum corresponding to the first fluid level; moving fluid into the shock strut in accordance with the first datum; calculating a second fluid level; generating a second datum corresponding to the second fluid level; and storing a final fluid level.

Abstract: System and methods for servicing and monitoring shock struts are provided. A shock strut servicing assistance system may comprise: a controller in electronic communication with a display; and a tangible, non-transitory memory configured to communicate with the controller, the tangible, non-transitory memory having instructions stored thereon that, in response to execution by the controller, cause the controller to perform operations comprising: calculating, by the controller, a dead volume of the shock strut; and determining, by the controller, if a dead volume of the shock strut is negative or not. The operations may further comprise receiving, by the controller, a temperature of a gas and at least one shock strut design parameter, wherein the calculating is performed using the temperature of the gas and the at least one shock strut design parameter.

Abstract: A system and various methods for monitoring and evaluating the health of a shock strut assembly are illustrated. Multiple sensors, including gas temperature, gas pressure, oil pressure, and position sensor, may be used to gather data and evaluate the performance of the shock strut assembly. Various methods illustrated herein may evaluate the dynamic damping, static load support, and/or controlled stroke performance of the shock strut assembly.

Abstract: A method includes detecting at least one position measurement of a separator piston of a pitch trim actuator. The method includes detecting at least one pressure measurement of an oil. The method includes detecting at least one temperature measurement of the oil. The method includes storing at least one position value based on the at least one position measurement of the separator piston, at least one pressure value based on the at least one pressure measurement of the oil and at least one temperature value based on the at least one temperature measurement of the oil. The method includes determining whether the pitch trim actuator requires servicing based on the at least one position value, the at least one pressure value, and the at least one temperature value.

Abstract: System and methods for servicing and monitoring shock struts are provided. A shock strut servicing assistance system may comprise: a controller in electronic communication with a display; and a tangible, non-transitory memory configured to communicate with the controller, the tangible, non-transitory memory having instructions stored thereon that, in response to execution by the controller, cause the controller to perform operations comprising: calculating, by the controller, a dead volume of the shock strut; and determining, by the controller, if a dead volume of the shock strut is negative or not. The operations may further comprise receiving, by the controller, a temperature of a gas and at least one shock strut design parameter, wherein the calculating is performed using the temperature of the gas and the at least one shock strut design parameter.