The paper considers the role of the breakdown of the adiabatic conditions for the propagation of sound in a gaseous layer adjacent to an interface between phases. It is shown that in the region of Knudsen numbers greater than 0.01 (frequency ω approx. 10 7-10 9 Hz under normal conditions), viscous and temperature waves become a significant mechanism for the radiation of energy of surface acoustic waves (SAWs). The paper describes for the first time experimental dependencies of the SAW attenuation coefficient on the frequency, the molecular mass of the gas and the pressure at high frequencies.