It is known that when the aircraft is moving the pressure on the runway and taxiway surfaces does not remain constant. One of the factors influencing starting aircraft rolling-off the runway is the low friction coefficient. The article analyses theoretical and experimental ways of defining the friction coefficient and it suggests a mathematical model taking into account the main factors influencing its magnitude. The wheel hydroplaning is the most unfavorable case of aircraft landing that takes

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... place on wet and slush covered runways with longitudinal and lateral adherence decreasing practically to zero. It was discovered in the research that the dynamic wheel hydroplaning is mostly affected by the following factors: the depth of the slush, its density, pressure in the wheels, degree of protector wear as well as the structure of runway surface. When modeling it is important to get to a true description of pneumatics as increase of damping speed reveals relaxation rubber properties where deformation changing is lagging behind load changing (it is necessary to take into account the non-liner and hysteresis properties). The article offers a method of assessing of the above mentioned phenomena on the basis of studying the interaction of undercarriage pneumatics with the runway surface with the help of using the system of mathematical modeling of aircraft flight dynamics. The article suggests methods of analytic describing aircraft moving on landing on the runway covered with slush.