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25 S e c t i o n V II Applicability to Airport Practice This project has assessed the temperature dependence of This project has completed the following for the CFM56- idling aircraft engine emissions for selected variants of the 7B24 engine: CFM56 engine type. The project has characterized engine emissions of on-wing commercial aircraft (equipped with Developed empirical corrections for fuel flow and tem- CFM56-7B24 engines) and explored the impact of fuel flows perature; below the ICAO reference fuel flow rate for idle. The test Demonstrated applicability of the corrections to both matrix development process incorporated airline guidance individual VOC species and UHC; on which fuel flow rates would be representative of actual idle Corroborated the near-idle VOC scaling effect (described phase during routine operation. in Section VI.2); The project's results, together with data from other sources, Demonstrated that emissions of HAP species can be esti- have been assimilated into an empirical model that strives to mated using the EPA Speciate profile with the ICAO data- describe the temperature and fuel flow dependence for near- bank UHC emissions performance value; and idle VOC emissions. The model described in this work is only Provided a tool for airport operators to compute near-idle appropriately applied to idling aircraft engines and ambient HAP and VOC emissions as a function of ambient tempera- temperatures between 260K and 310K (8 F to 98F). It is ture and airport operational conditions. currently based on the observations of the CFM56 engine. The project has proposed a framework for data assimilation that can tie future observations to ICAO certification data. The results from this study can be applied in detailed anal- The approach described in this study can be used to estimate ysis to study the HAP/VOC emissions trade-offs for a variety emissions during airport operations in the context of scenario of scenarios, such as the following: analysis. The simple model described in this work can be used to help quantify the emissions benefit from proposed Optimizing the takeoff queue length during operational improvements to terminal area and taxiway operational pushes, protocols. Based on the observed temperature dependence, Quantifying the benefit of switching to APU during cold it is clear that practices that limit the amount of excess time weather ground stop, and spent at idle during the winter months will significantly limit Assessing HAP and VOC benefits from single engine the HAP emissions burden. taxiing.