Abstract: A method and apparatus for the real time estimation of the location of the center of gravity in an aircraft using a linear estimation technique. The center of gravity estimate is used in the aircraft's flight control system (12) to implement flight control laws that depend on the aircraft's center of gravity. The center of gravity is initially estimated based on signals indicative of the aircraft angle of attack, flap setting, elevator position, and stabilizer position. The initial approximation is then refined by multiplying or dividing the center of gravity estimate by additional factors including the weight of the aircraft, the expected load factor on the aircraft, the dynamic pressure on the aircraft, and the reference wing area of the aircraft. The resulting center of gravity estimate is measured as a percentage of the mean aerodynamic chord (MAC) of the aircraft.

Abstract: Disclosed is a method of and an arrangement for generating a ground effects compensated aircraft body angle of attack signal. The disclosed method includes converting an aircraft pitch rate corrected alpha vane signal to a free air body angle of attack signal that is calibrated to the type of aircraft that employs the invention for the two conventional landing flap settings. The free air body angle of attack signal then is processed to obtain an alpha vane correction signal that represents ground effects compensation that would be required at zero altitude (aircraft touchdown). The zero altitude alpha vane correction signal is then multipled by an altitude scaling signal and converted to a ground effects compensation signal that is applicable to the then current altitude of the aircraft. The ground effects compensation signal then is summed with the free air corrected body angle of attach signal to provide the ground effects compensated body angle of attack signal of the invention.