Abstract: A method for monitoring a shock strut may comprise measuring a first shock strut pressure, measuring an ambient temperature, measuring a shock strut stroke, measuring a second shock strut pressure, and determining a servicing condition of the shock strut based upon the first shock strut pressure, the ambient temperature, the shock strut stroke, and the second shock strut pressure, wherein the servicing condition indicates whether it is desirable for the shock strut to be serviced with at least one of a liquid and a gas. The first shock strut pressure and the shock strut stroke may be measured before the takeoff event with a weight of an aircraft supported by the shock strut.

Abstract: A method for monitoring a shock strut may comprise measuring a first shock strut pressure, measuring an ambient temperature, measuring a shock strut stroke, measuring a second shock strut pressure, and determining a servicing condition of the shock strut based upon the first shock strut pressure, the ambient temperature, the shock strut stroke, and the second shock strut pressure, wherein the servicing condition indicates whether it is desirable for the shock strut to be serviced with at least one of a liquid and a gas. The first shock strut pressure and the shock strut stroke may be measured before the takeoff event with a weight of an aircraft supported by the shock strut.

Abstract: A method for monitoring a shock strut may comprise measuring a first shock strut pressure, measuring an ambient temperature, measuring a shock strut stroke, measuring a second shock strut pressure, and determining a servicing condition of the shock strut based upon the first shock strut pressure, the ambient temperature, the shock strut stroke, and the second shock strut pressure, wherein the servicing condition indicates whether it is desirable for the shock strut to be serviced with at least one of a liquid and a gas. The first shock strut pressure and the shock strut stroke may be measured before the takeoff event with a weight of an aircraft supported by the shock strut.

Abstract: A shock strut assembly for a landing gear may comprise a strut cylinder, a strut piston configured to telescope relative to the strut cylinder, and a locking system. The locking system may be configured to restrict rotation of the strut piston relative to the strut cylinder in response to compression of the shock strut assembly.

Abstract: A method for monitoring a dual-stage shock strut may include measuring a first primary chamber pressure when the dual-stage shock strut is in a first state, measuring a first secondary chamber pressure when the dual-stage shock strut is in the first state, measuring a shock strut stroke when the dual-stage shock strut is in the first state, measuring a first temperature, measuring a second temperature, measuring a second primary chamber pressure when the dual-stage shock strut is in a second state, measuring a second secondary chamber pressure when the dual-stage shock strut is in the second state, and determining a servicing condition of the shock strut based upon at least the first primary chamber pressure, the first secondary chamber pressure, the shock strut stroke, the first temperature, the second temperature, the second primary chamber pressure, and the second secondary chamber pressure.

Abstract: A method for monitoring a dual-stage, separated gas/fluid shock strut includes receiving, by a controller, a primary chamber temperature sensor reading, a primary chamber pressure sensor reading, and a shock strut stroke sensor reading, calculating, by the controller, a secondary chamber nominal pressure based upon the primary chamber temperature sensor reading, 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, a volume of gas in a primary gas chamber, a number of moles of gas in the primary gas chamber, a volume of oil leaked into the primary gas chamber, a volume of gas in a secondary chamber, and a number of moles of gas in the secondary chamber.

Abstract: A method for monitoring a dual-stage, stroke activated, mixed fluid gas shock strut includes receiving, by a controller, primary chamber temperature and pressure sensor readings, secondary chamber pressure and temperature sensor readings, and a shock strut stroke sensor reading, calculating, by the controller, a compression factor, determining, by the controller, a plurality of compression factors for known oil volumes based on the primary chamber temperature sensor reading and/or the shock strut stroke sensor reading, and calculating, by the controller, an oil volume in a primary chamber of the shock strut, a number of moles of gas in the primary chamber of the shock strut, a volume of gas in a secondary chamber of the shock strut, and a number of moles of gas in the secondary chamber.

Abstract: A method for monitoring a dual-stage, separated gas/fluid shock strut includes receiving, by a controller, primary chamber temperature and pressure sensor readings, secondary chamber pressure and temperature sensor readings, and a shock strut stroke sensor reading, determining, by the controller, a shock strut stroke at which a secondary chamber is activated, calculating, by the controller, a volume of oil in an oil chamber of the shock strut, a primary chamber gas volume of, a number of moles of gas in, and a volume of oil leaked into, a primary gas chamber of the shock strut, a secondary chamber gas volume in, a volume of oil leaked into, and a number of moles of gas in, the secondary chamber, based upon at least one of the secondary chamber pressure sensor reading, and the secondary chamber temperature sensor reading.

Abstract: A shock strut assembly for a landing gear may comprise a strut cylinder, a strut piston configured to telescope relative to the strut cylinder, and a locking system. The locking system may be configured to restrict rotation of the strut piston relative to the strut cylinder in response to compression of the shock strut assembly.

Abstract: A system and various methods for determining a center of mass of an aircraft with a plurality of shock strut assemblies is illustrated. Multiple sensors, including a gas pressure sensor, and/or a position sensor, may be used to gather data and determine the center of mass of the aircraft. Various methods illustrated herein may evaluate the center of mass relative to a wheelbase axis and a wheel tread axis based on the gathered data.

Abstract: A system and various methods for determining a center of mass of an aircraft with a plurality of shock strut assemblies is illustrated. Multiple sensors, including a gas pressure sensor, and/or a position sensor, may be used to gather data and determine the center of mass of the aircraft. Various methods illustrated herein may evaluate the center of mass relative to a wheelbase axis and a wheel tread axis based on the gathered data.

Abstract: A method for servicing a dual-stage, mixed 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 a primary chamber of the shock strut, and charging the primary chamber with compressed gas.

Abstract: A method for monitoring a dual-stage, stroke activated, mixed fluid gas shock strut includes receiving, by a controller, primary chamber temperature and pressure sensor readings, secondary chamber pressure and temperature sensor readings, and a shock strut stroke sensor reading, calculating, by the controller, a compression factor, determining, by the controller, a plurality of compression factors for known oil volumes based on the primary chamber temperature sensor reading and/or the shock strut stroke sensor reading, and calculating, by the controller, an oil volume in a primary chamber of the shock strut, a number of moles of gas in the primary chamber of the shock strut, a volume of gas in a secondary chamber of the shock strut, and a number of moles of gas in the secondary chamber.

Abstract: A method for monitoring a dual-stage, separated gas/fluid shock strut includes receiving, by a controller, primary chamber temperature and pressure sensor readings, secondary chamber pressure and temperature sensor readings, and a shock strut stroke sensor reading, determining, by the controller, a shock strut stroke at which a secondary chamber is activated, calculating, by the controller, a volume of oil in an oil chamber of the shock strut, a primary chamber gas volume of, a number of moles of gas in, and a volume of oil leaked into, a primary gas chamber of the shock strut, a secondary chamber gas volume in, a volume of oil leaked into, and a number of moles of gas in, the secondary chamber, based upon at least one of the secondary chamber pressure sensor reading, and the secondary chamber temperature sensor reading.

Abstract: A method for monitoring a dual-stage, separated gas/fluid shock strut includes receiving, by a controller, a primary chamber temperature sensor reading, a primary chamber pressure sensor reading, and a shock strut stroke sensor reading, calculating, by the controller, a secondary chamber nominal pressure based upon the primary chamber temperature sensor reading, 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, a volume of gas in a primary gas chamber, a number of moles of gas in the primary gas chamber, a volume of oil leaked into the primary gas chamber, a volume of gas in a secondary chamber, and a number of moles of gas in the secondary chamber.

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 dual-stage, separated gas/fluid shock strut arrangement includes a dual-stage, separated gas/fluid shock strut, a pressure/temperature sensor mounted to the primary gas chamber, a stroke sensor, and a monitoring system, comprising a recorder configured to receive a plurality of sensor readings from at least one of the pressure/temperature sensor and the stroke sensor, a landing detector configured to detect a landing event based upon a stroke sensor reading received from the stroke sensor, and a health monitor configured to determine a volume of oil in the oil chamber, a volume of gas in the primary gas chamber, and a volume of gas in the secondary gas chamber.

Abstract: A dual-stage, stroke activated, mixed fluid gas shock strut arrangement includes a dual-stage, stroke activated, mixed fluid gas shock strut (shock strut) and a monitoring system. The shock strut includes a strut cylinder, a strut piston, a primary chamber comprising an oil chamber and a primary gas chamber, and a secondary gas chamber. The monitoring system includes a first pressure/temperature sensor, a second pressure/temperature sensor, a stroke sensor, a recorder configured to receive a plurality of sensor readings from the first pressure/temperature sensor, the second pressure/temperature sensor, and/or the stroke sensor, a landing detector configured to detect a landing event based upon a stroke sensor reading received from the stroke sensor, and a health monitor configured to determine an oil volume in the primary chamber, wherein the health monitor calculates a compression factor to determine the oil volume.

Abstract: A dual-stage, separated gas/fluid shock strut arrangement includes a dual-stage, separated gas/fluid shock strut and a monitoring system. The shock strut includes a strut cylinder, a strut piston operatively coupled to the strut cylinder, an oil chamber, a primary gas chamber, and a secondary gas chamber. The monitoring system includes a first pressure/temperature sensor, a second pressure/temperature sensor, a stroke sensor, a recorder configured to receive a plurality of sensor readings from the first pressure/temperature sensor, the second pressure/temperature sensor, and/or the stroke sensor, a landing detector configured to detect a landing event based upon a stroke sensor reading received from the stroke sensor, and a health monitor configured to determine a volume of oil in the oil chamber, a primary chamber gas volume in the primary gas chamber, and a secondary chamber gas volume in the secondary gas chamber.

Abstract: A method for monitoring a dual-stage shock strut may include measuring a first primary chamber pressure when the dual-stage shock strut is in a first state, measuring a first secondary chamber pressure when the dual-stage shock strut is in the first state, measuring a shock strut stroke when the dual-stage shock strut is in the first state, measuring a first temperature, measuring a second temperature, measuring a second primary chamber pressure when the dual-stage shock strut is in a second state, measuring a second secondary chamber pressure when the dual-stage shock strut is in the second state, and determining a servicing condition of the shock strut based upon at least the first primary chamber pressure, the first secondary chamber pressure, the shock strut stroke, the first temperature, the second temperature, the second primary chamber pressure, and the second secondary chamber pressure.