Mitigating environmental impacts using aircraft operations: A systematic overview and a focus on end-around taxiways

Concerns about the aviation\u27s environmental impact have prompted research efforts around the world. Much of this research has focused on changes to future aircraft and engine designs. However, it will take a long time for these changes to be developed and propagate through the operational fleet in sufficient numbers to have a significant impact on overall emission levels. Until then, operational mitigations that reduce the environmental impacts of existing aircraft will be the most effective strategies. Part I of this thesis involved the identification and qualitative assessment of operational changes that could mitigate aviation’s environmental footprint in the near-term. This resulted in the development of a comprehensive list of mitigation strategies that indicated environmental mitigation potential of various operational changes. Part II of this research effort focused on a specific mitigation measure, that is, the use of end-around taxiways at high-traffic airports with parallel runways. An explicit evaluation of the environmental implications of these taxiways at a candidate airport, DFW (Dallas/Fort-Worth International Airport) was conducted. Observed usage patterns indicated that the use of the end-around taxiway varied significantly on a daily basis. Since operations on the taxiway did not follow strict procedures, there existed the potential to develop procedures for the effective use of the end-around taxiway, in terms of surface fuel burn reduction. A focused investigation on a short taxi segment in the southeast quadrant at DFW revealed that that, while the end-around taxiway shows significant promise in terms of fuel burn and emissions reduction, these benefits depend on the manner of operation of the taxiway. Factors such as traffic conditions on adjacent runways, traffic flow direction, arrival time of aircraft, and the specific aircraft type play a major role in extracting environmental benefits from end-around taxiways. For example, the results showed that the average fuel burn for aircraft using the end-around taxiway was less than the average fuel burn of aircraft using a conventional taxiway during a select portion of the day, specifically, between 5pm and 1am. Decision rule-based studies showed that always or never using the end-around taxiway did not bring about environmental benefits. Further, implementation of decision rules based on the results of this research showed promise in terms of fuel burn reduction. Hence, better understanding of the factors that affect endaround taxiway operations and the manner in which they should be used could lead to the development of improved taxiway procedures that maximize the environmental benefits of the EAT