A general purpose computer program DADS has been used to study the landing gear response on battle damaged, repaired runways during aircraft landing, taxing and take off. Two types of gears have been modeled. One is a cantilever type gear, the other is an articulated gear. The hydraulic orifice damping, pneumatic air spring, bearing friction forces in the shock strut and the tire-load deflection curve are all included in the models. The output includes the tire-ground reaction force, the shock strut dynamic load and the forces in each members of the gear.These two gear models are built in a three dimensional space, and they can be used either as a single gear running over a runway repair mat, or combined together to simulate a whole aircraft operating on a rough field.The study shows the great capability of DADS in the modeling, simulation and analysis of aircraft ground operations. Rather than writing a generic FORTRAN source code, using the DADS is much easier and more flexible for the user to model and study most types of landing gear systems in a much shorter time frame.