Definition of waiver. 1  1 : the act of intentionally relinquishing or abandoning a known right, claim, or privilege; also : the legal instrument evidencing such an act.
Roll, pitch and yaw. Roll, pitch and yaw are rotations along the natural axes of the helicopter (or any aircraft). A rolling movement is where the helicopter rotates along a line along its length using lateral cyclic inputs (aileron), eventually turning from right way up to inverted while maintaining the helicopter's heading.
A skid is defined as a yaw event. Yaw is a rotational force generated when it is cornering. Center of gravity is the point at which a vehicle rotates in a corner at high speed. The yaw sensor, a Coriolis-type sensor, is located at the center of gravity. The Coriolis effect depends on the velocity of the moving object (a vehicle in a cornering maneuver), and centrifugal force, which does not depend on the velocity of the moving object (the rotation of the chassis in a skid).