Potential Assessment and Initial Design for a Fuel and Noise Reducing Trajectory Optimisation System for Turboprop Aircraft Based on ADS-B Data

Abstract

The German Aerospace Center (DLR) has developed and successfully proved the Low Noise Augmentation System (LNAS) for turbofan aircraft. LNAS assists pilots with their speed and aircraft configuration management during approach in order to increase fuel efficiency, decrease noise exposure on ground, and being stabilised at 1000 ft above threshold elevation. The operation of turboprop aircraft differs from turbofan aircraft in the mission profile and the operating procedures. The flight performance is characterised by significantly lower cruise speeds and altitudes compared to turbofan aircraft. However, they are more fuel efficient and less maintenance demanding. These advantages result in lower operational costs and less CO2 emissions that underline the relevance of turboprop aircraft more for the future. This paper describes the assessment of a potential benefit and the initial design of a similar trajectory optimisation system for turboprop aircraft. It further provides some basics about turboprop aircraft, the description of the recording and processing of broadcasted ADS-B data performed to gather simple flight data of approaching turboprop aircraft (Dornier 328-100). Afterwards, it describes the estimation of relevant flight parameters from processed data and the analysis regarding a potential to improve fuel efficiency and reduce noise. The recorded ADS-B data show a strong variation in altitude and speed profiles with track distance. Furthermore, the calculated derivations of the aircraft's total energy indicate an energy supply which is likely caused by the engine power lever. These findings in ADS-B data suggest the presence of an optimisation potential to improve the energy management of turboprop aircraft during approach. In addition, the findings are supported by the availability of a small number of high-quality flight test data from DLR's UpLift Dornier 328-100 research aircraft (D-CUPL). Lastly, this paper describes and discusses the initial concept of an appropriate optimisation system, including the design of corresponding cockpit display indications that are needed to assist the cockpit crew during approach. Research on the described concept of trajectory optimisation and its realisation is being continued at DLR in order to contribute to sustainable aviation in the future.