both the brain and oculomotor muscles, stabilizing eye movements. A transfer function model between the perceived angular displacement and the actual angular displacement is: A second-order model of the angle of the cupula is given by where is the damping ratio, is the natural frequency of the cupula, and is the input angular acceleration. Values of have been reported to be between 3.6 and 6.7 while values of have been reported to be between 0.75 and 1.9. Thus, the system is overdamped with distinct, real roots. The shorter time constant is 0.1 seconds, while the longer time constant depends on the axis about which the test subject is accelerating (roll, pitch, or yaw). These time constants are one to two orders of magnitude greater than the shorter time constant. Experiments have shown that angular accelerations below a certain level cannot be detected by a human test subject. Values of have been reported for pitch and roll accelerations in a flight simulator. Implications The above studies indicate that the pilot's vestibular system detects accelerations before the aircraft instruments displays them. This can be considered an inner control loop in which the pilots responds to accelerations that occur in full-motion simulators and aircraft, but not in fixed simulators. This effect shows that there is a potential negative training transfer when transitioning from a fixed-based simulator to an aircraft and indicates the need for motion systems for full-fidelity pilot training. It is physically impossible to precisely simulate large scale real motion in the limited space of a laboratory. The standard approach to simulating motion (so called motion cueing) is to simulate the “relevant” cues as closely as possible which trigger motion perception. These cues can be visual, auditory, or somatosensory in nature. Visual and auditory cues enable humans to perceive their location in space on an absolute scale, whereas somatosensory cues (mainly proprioception and other signals from the vestibular system) provide only feedback of accelerations. For example, consider riding in a car traveling at some arbitrary constant speed. In this situation, our sense of sight and sound provide the only cues (excluding engine vibration) that the car is moving; no other forces act on the passengers of the car except for gravity. Next, consider the same example of a car moving at constant speed except this time, all passengers of the car are blindfolded. If the driver were to step on the gas,