Boeing 747-8 System Practice Exam

The question is about how the AFDS stabilizes the airplane when an engine fails before the approach. In an engine-out condition, the airplane has a natural yaw and roll tendency from the asymmetric thrust. To keep the approach stable and keep the wings level, the AFDS is programmed to transition into a wings-level sideslip at a specific point in the descent. That transition occurs at about 1300 ft AGL. This timing gives enough vertical room and control authority to bleed off the asymmetry, align with the intended flight path, and maintain a stable, wings-level configuration as you continue the approach and prepare for the final descent. Beginning the sideslip too low would risk getting to the runway with insufficient margin to reconfigure the flight path safely; starting too high would delay stabilization and could require more aggressive control inputs closer to the runway. So, when an engine fails prior to the approach, the aircraft’s AFDS will introduce a sideslip to wings level at 1300 ft AGL to promote a safe, stable approach configuration.