Impact of aircraft systems within aircraft operation: A MEA trajectory optimisation study

摘要

Air transport has been a key component of the socio-economic globalisation. The everincreasing demand for air travel and air transport is a testament to the success of the aircraft.But this growing demand presents many challenges. One of which is the environmental impactdue to aviation. The scope of the environmental impact of aircraft can be discussed from manyviewpoints. This research focuses on the environmental impact due to aircraft operation.Aircraft operation causes many environmental penalties. The most obvious is the fossil fuelbased fuel burn and the consequent greenhouse gas emissions. Aircraft operations directlycontribute to the CO2 and NOX emissions among others. The dependency on a limited naturalresource such as fossil fuel presents the case for fuel optimised operation. The by-products ofburning fossil fuel some of which are considered pollutants and greenhouse gases, presentsthe case for emissions optimised operations. Moreover, when considering the local impact ofaircraft operation, aircraft noise is recognised as a pollutant. Hence noise optimised aircraftoperation needs to be considered with regards to local impacts. It is clear whichever theobjective is, optimised operation is key to improving the efficiency of the aircraft.The operational penalties have many different contributors. The most obvious of which is theway an aircraft is flown. This covers the scope of aircraft trajectory and trajectory optimisation.However, the design of the aircraft contributes to the operational penalties as well. For examplethe more-electric aircraft is an improvement over the conventional aircraft in terms of overallefficiency. It has been proven by many studies that the more-electric concept is more fuelefficient than a comparable conventional aircraft.The classical approach to aircraft trajectory optimisation does not account for the fuel penaltiescaused due to airframe systems operation. Hence the classical approach cannot define aconventional aircraft from a more-electric aircraft. With the more-electric aircraft expected tobe more fuel efficient it was clear that optimal operation for the two concepts would be different.This research presents a methodology that can be used to study optimised trajectories formore-electric aircraft.The study present preliminary evidence of the environmental impact due to airframe systemsoperation and establishes the basis for an enhanced approach to aircraft trajectory optimisationwhich include airframe system penalties within the optimisation loop. It then presents a suite of models, the individual modelling approaches and the validation to conduct the study. Finallythe research presents analysis and comparisons between the classical approach where theaircraft has no penalty due to systems, the conventional aircraft and the more-electric aircraft.When the case studies were optimised for the minimum fuel burn operation, the conventionalairframe systems accounted for a 16.6% increase in fuel burn for a short haul flight and 6.24%increase in fuel burn for a long haul flight. Compared to the conventional aircraft, the moreelectric aircraft had a 9.9% lower fuel burn in the short haul flight and 5.35% lower fuel burn inthe long haul flight. However, the key result was that the optimised operation for the moreelectricaircraft was significantly different than the conventional aircraft. Hence this researchcontributes by presenting a methodology to bridge the gap between theoretical and realaircraft-applicable trajectory optimisation.