Enhanced Self-Spacing Algorithm for Three-Degree Decelerating Approaches

A current trend in aircraft noise abatement around airports is exploiting the benefits of revised arrival and approach procedures with computational aids, such as onboard and ground-based trajectory prediction algorithms and displays. The challenge for these upcoming advanced noise abatement procedures is to mitigate the noise impact without sacrificing runway capacity. A proposed solution, implemented in the three-degree decelerating approach, is to delegate the task of spacing the aircraft to the cockpit during the approach. To assist the pilots, a flap scheduling algorithm with complementary interface has been developed that takes noise nuisance and in-trail spacing into account. The design and functionality of this support system is presented and evaluated with three experiments. Monte Carlo simulations indicated adequate and consistent performance and robustness of the self-spacing algorithm for various wind and traffic scenarios. A pilot-in-the-loop simulator experiment verified that, with the aid of the algorithm, pilots were able to execute the noise abatement procedure consistently while maintaining safe spacing. The support system reduced pilot workload up to an effort level comparable to current standard approaches. The concept was demonstrated in flight, which confirmed the conflict-free performance benefits and the feasibility of self-spacing during continuous decelerating/descent approaches under actual flight conditions.