A system for use in monitoring, measuring, computing and displaying the rate of compression of aircraft landing gear struts, experienced while aircraft are executing either normal or hard landing events. Further by measuring the vertical compression rate of the landing gear strut, thus with aircraft hull angle correction to horizontal, determining the vertical sink-rate of the aircraft, as it comes into initial contact with the ground. Accelerometers are attached to opposing sides of a compressible landing gear strut, monitoring and measuring parallel data streams; then identifying differential acceleration data streams, which computed through mathematical algorithms measure the collapse rate of the landing gear strut. Pressure sensors are attached to the working pressure within the landing gear strut, so to monitor in-flight landing gear strut pre-charge pressure, until such time as the pre-charge pressure suddenly increases, to detect the aircraft has come into initial contact with the ground. A method of operating an aircraft at an increased maximum landing weight limitation.