Abstract: Disclosed is a method of and apparatus for processing flight control signals in an automatic landing system so that automatic landings can be executed within the bounds of current certification requirements (Category III weather minimums) and in a manner that in effect emulates standard manual landing procedures. Included is provision for introducing engine-out sideslip that insures that the automatic landing approach and touchdown is made with the aircraft wings level or with the upwind wing low. Also provided is the generation of rudder and wheel (aileron) compensation for lateral ground effects that occur during a landing with sideslip when the aircraft altitude is approximately one wingspan or less. Provision also is made for rudder control to offset yawing moment that occurs when the thrust of the operative engines is retarded prior to touchdown.

Abstract: Disclosed is a method of and apparatus for generating a signal representative of aircraft gear altitude after the flare maneuver is initiated in an automatic landing procedure. In accordance with the invention, the gear altitude signal is produced by complementary filtering of the aircraft gear altitude signal and the aircraft inertial vertical acceleration signal, with the complementary filter frequency being varied so that the aircraft filtered gear altitude signal primarily is produced on the basis of the vertical inertial acceleration signals prior to the time at which the aircraft reaches the runway threshold and is primarily produced on the basis of the aircraft gear altitude signal after the aircraft crosses runway threshold. The result is the reduction of the filtered gear altitude signal variation that can be caused by irregular terrain along the landing approach path while maintaining signal sensitivity to runway slope and runway slope variation.

Abstract: A controller for generating a bank angle limit for an aircraft during takeoff with an nonoperational engine. The controller operates so that there are minimum and maximum bank angle limits. Between these minimum and maximums, there is a linear relationship between aircraft airspeed and bank angle limit. However, before there is a change in aircraft airspeed from an increasing mode to a decreasing mode or vice versa, the bank angle limit remains constant until the change in aircraft airspeed is greater than or equal to a predetermined airspeed differential.

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.

Abstract: Disclosed is a method of and an arrangement for real time estimation of the location of the center of gravity of an aircraft. The center of gravity estimate is utilized in an aircraft flight control system for effecting flight control laws in which the center of gravity is a parameter that at least in part establishes open loop compensation or feedback gain. The disclosed method and arrangement are specifically adapted for establishing stabilizer mistrim during a landing procedure in which an aircraft flight control system is automatically controlling the aircraft. The method generally comprises the steps of generating a signal that represents the product of the aircraft stabilizer position and a multiplicative factor, A.sub.1 and adding to that product an additive factor, A.sub.2. The multiplicative factor, A.sub.1, and the additive factor, A.sub.2, both are determined on the basis of the angle of attack of the aircraft and the aircraft flap setting.

Abstract: Disclosed is a method of and apparatus for determining the flare height at which the flare maneuver of an automatic landing procedure is initiated. The method includes the step of generating an adjusted approach sink rate signal, which depends on the ground speed of the aircraft during a landing approach and is compensated for short term deviations from the glideslope angle.