Method and apparatus for an improved autopilot system providing for late runway change

摘要

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.