A system for vibrating a seat within the cockpit of a flight trainer to simulate aircraft buffeting. The seat is mounted at its rear on a pair of linear bearings which permit z axis movement of the seat relative to the trainer cockpit. A hydraulic actuator, acting through a bell crank and link, vibrates the seat up and down under computer control. The computer determines the required seat vibration frequency and amplitude as a function of simulated aircraft angle of attack and maneuvering load factor. Analog signals representing the computed vibration frequency and amplitude are fed to a voltage controlled ramp generator which provides a seat driving signal to the hydraulic actuator through a closed loop servo system.