In modern aircraft, the flying performance, design of the airframe, engines, armament, or the military purpose are the features of principal interest, while the efficiency of the undercarriage is usually known only to a limited number of specialists. Shock-absorber legs, wheels and brakes are now such highly developed structural components that they deserve special attention. In the following, modern types of wheels and bra kes are described in detail and following, modern types of wheels and brakes are described in de the theoretical basis for the calculation of the landing process discussed.