Patent ID: 6158695
Filing Date: 2000-12-12
Classification: B64C,G05D,Y02T

Abstract:
A method of providing speed protection to a neutrally-stable aircraft, the aircraft including a pitch control system having a commanded pitch signal received from pilot input to a control column, the method comprising:(a) calculating at least one of a stall protection signal and an overspeed protection signal;wherein calculating the stall protection signal includes calculating the difference between the aircraft's current filtered airspeed and a stick shaker reference speed and multiplying the difference by a scaling factor that corresponds to the force required by the pilot to move the control column, the scaling factor causing more force to be exerted by the pilot on the control column when attempting to increase pitch at low speeds; the stick shaker reference speed being set to an amount based on the aircraft's amber band speed value; andwherein calculating the overspeed protection signal includes calculating a first overspeed protection signal based on airspeed, calculating a second overspeed protection signal based on Mach, selecting the larger of the two overspeed protection signals, passing the larger amount through a limiter that is a function of roll attitude and that corresponds to the force required by the pilot to move the control column, the passing through the limiter thereby causing more force to be exerted by the pilot on the control column when attempting to decrease pitch at high speeds; and(b) providing the at least one stall protection signal and overspeed protection signal to the pitch control system for use in limiting the commanded pitch signal during flight; the inclusion of a stall protection signal to the pitch control system resulting in a pilot-overridable nose-down movement of the aircraft; the inclusion of an overspeed protection signal to the pitch control system resulting in a pilot-overridable nose-up movement of the aircraft.