Abstract: An improvement to an autopilot flight director system allows the flight crew to make a late runway change without disengaging the autopilot. The improved system allows a transition to a new runway assignment if radio altitude is greater than 1500 feet. Control logic determines whether or not localizer and/or glideslope have been captured and enters predetermined modes as a function thereof to effect a transition to the new approach while enabling instrument landing system retuning while maintaining autopilot engagement. Flight crew workload during approach is significantly reduced as a result of implementation of the improved system.

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 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.