During the past several years the problem of wake turbulence has received considerable attention. As a result of research programs sponsored by the Federal Government and private industry, the hazard of wake turbulence to light aircraft has been well documented. In this paper it is emphasized that relatively large aircraft can also be susceptible to vortices generated by large jet transports. This conclusion is based upon a review of accident records and the results from a computer simulation of the aircraft-vortex interaction. The computer simulation consists of the equations of motion with six degrees of freedom as well as control input by the pilot. Procedures are recommended for avoiding dangerous vortex encounters.