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In recent years the AFFDL has actively attempted to develop improved techniques and criteria for providing aircraft with a capability for landing on substandard fields. A number of R&D programs have been conducted to this end. These programs have involved the participation of not only the AFFDL Landing Gear Test Facility, but also the Vicksburg Waterways Experiment Station, and various aircraft and landing gear contractors. The scope of approaches investigated includes expandable tires, extra wide tires, low pressure tires, track gear, air cushion gear, and basic flotation criteria. This paper summarizes the significant results of these programs. The paper briefly summarizes the presently available criteria for ground flotation on bare soil and indicates approaches for improving aircraft ground flotation characteristics. Also included are the results of AFFDL tests of conventional tires tested at high deflection, and of unconventional (expandable) tires which collapse for stowage.

The CVS/ATB (Crash Victim Simulator/ Articulated Total Body) computer program solves the equations of motion in three dimensional space for a set of rigid bodies connected by joints. The program permits the specification of contact interaction properties between the rigid bodies and the surrounding environment. It is, therefore, possible to specify initial conditions of motion for the rigid bodies, and calculate the subsequent motion resulting from the forces imposed by the environment. The program is sufficiently general that it can be applied to a wide range of physical dynamic situations. However, the principal motivation for its development was to evaluate the interactions of the human body with the environment inside a motor vehicle during a crash. Subsequently, it has been applied to a number of other dynamic simulations including pedestrian to vehicle impacts and the emergency escape of air crew from aircraft. The CVS/ATB program is in the public domain.