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.