Value of an Overload Indication System Assessed Through Analysis of Aviation Occurrences

This paper identifies the value of an aircraft landing gear overload indication system by comparing vertical descent velocity landing data extrapolated from a statistical analysis of the Federal Aviation Administration's Video Landing Parameter Survey data, with reported occurrence data. Data suggest that there should be between 455-848 narrow-body aircraft and between 236-1279 heavy-wide-body aircraft per million departures, with a vertical descent velocity above the hard-landing threshold of 10 ft=s, and that flight crews declare hard landings at a frequency even higher than predicted by the Federal Aviation Administration data. Analysis of aviation authority and landing gear manufacturer data show that occurrences are reported at a much lower frequency than the 10 ft=s vertical descent velocity threshold or flight-crew declaration rates. This could be interpreted as suggesting that more hard landings occur than are reported. However, the discrepancy between the vertical descent velocity data and the reported occurrence data can be attributed to 1) Federal Aviation Administration data being based solely on vertical descent velocity without taking into account the other critical enveloping flight parameters required to calculate the loads in the landing gear structure and 2) reported occurrences being filtered in an authorized occurrence assessment process. Having reviewed the occurrence assessment process, it is argued that an overload indication system offers potential benefits through 1) improved aircraft operational availability; 2) reduced costs for the operator, aircraft manufacturer, and landing gear manufacturer; and 3) reduced risk to the aircraft and operator. [PUBLICATION ABSTRACT]