SEA-ICE BEARING STRENGTH IN ANTARCTICA - AIRCRAFT LOAD CURVES FOR MCMURDO ICE RUNWAY

To update the operating criteria for C-121, C-124, C-130, C-141, and C-5 aircraft in the Antarctic, the bearing capacity of the McMurdo annual sea- ice sheet was analyzed for short-term loading. The load curves developed by elastic theory predict the ice thickness required as related to the changing strength characteristic of the ice sheet associated with the seasonal warming trend. These load curves provide operating criteria that are more related to the ice-sheet temperature than the operating criteria now in use. This analysis is only an interim solution in the development of aircraft operating criteria; continued research is needed to provide a better understanding of the ice-sheet response to both short- and long-term loads. The load curves and instructions presented in Appendix B are recommended to replace the present operating criteria appearing in NCEL Technical Note N-888, 'Interim Aircraft Load Curves for Sea-Ice Runways at McMurdo, Antarctica.'