Improving Aircraft Energy and Flightpath Management through Pilot Support Functions: Demonstration of Optimized Continuous Descent Approaches with the Airbus A320neo at Zurich Airport

Abstract

Managing aircraft energy and flightpath during descent remains one of the major operational challenges for pilots. Advancements in this area are therefore essential for enhancing the efficiency, safety and environmental impact of modern flight operations. Within the framework of the EU-funded SESAR ALBATROSS project, the Low-Noise Augmentation System (LNAS) was successfully tested on Airbus A320neo aircraft operating along a closed-path Performance-Based Navigation (PBN) transition to Instrument Landing System (ILS) at Zurich Airport (LSZH), Runway 14. In this study, Continuous Descent Approaches (CDA) were flown both with and without LNAS pilot assistance during regularly scheduled Swiss International Air Lines flights, enabling a direct comparison under real-world operational conditions. The aim of the study was to investigate whether real-time visual cues regarding aircraft energy and aircraft configuration could support pilots in reducing fuel consumption and noise by maximizing distance flown at minimum thrust, minimizing the use of speed brakes and applying configuration changes at optimum locations. Skyguide published a temporary PBN-to-ILS transition to give the pilots in both evaluation groups the ability to fly the approach transition laterally in navigation mode, providing them with complete knowledge of the remaining distance-to-go (DTG) to touchdown. The pilots were specifically trained in the use of LNAS. Data were collected over 23 approaches from July to December 2022. The study was complemented by comparison with 547 flights outside of this trial, which were recorded over the same time period without any pilot assistance function or closed-path procedure. This enabled the comparison of energy management, aircraft configuration changes, and fuel burn with current flight operations. Results show that LNAS increased the predictability of the airspeed and the vertical profile. Furthermore, LNAS minimized the need for speed brake deployment at lower altitudes, thus reducing noise near the airport. Quantitatively, average fuel consumption decreased by 8.8% over the final 30 nautical miles to touchdown compared to flights without pilot assistance. The visual cues provided by the pilot assistance system were qualitatively assessed against the EASA pilot core competencies to derive recommendations for future deployment of such novel functionalities. The findings confirm that incorporating such pilot assistance functions into a future Flight Management System (FMS) could enhance the management awareness of the aircraft’s energy state. Besides fuel saving, better aircraft energy management supports approach stabilization and minimizes flightpath deviations, thereby contributing to flight safety.