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46 airport emissions modeling tool--Emissions and Dis- levels less than 7% can be more than twice as high as persion Modeling System (EDMS). This will allow the emission rate at the certification value (7% airport operators to utilize the latest scientific findings thrust). Variation in the thrusts used during take-off to construct HAPs emission estimates tailored to their can greatly impact NOx emissions as well. Such dif- specific airport. These estimates will be more defensi- ferences in the emission rate with small changes in ble and better able to withstand litigation since they thrust level are sufficiently large to introduce large will be based on the latest scientific findings regarding errors in emission inventories. Since airport operators jet engine HAPs emissions and the variables that use these emission inventories to evaluate mitigation affect them. strategies, the accuracy must be improved to reflect real-work thrust conditions. VII. RELATED RESEARCH See ACRP 02-03 report. III. OBJECTIVE The principal objective of this research is to generate VIII. PERSON(S) DEVELOPING THE PROBLEM an input function for the Emissions Dispersion Mod- ACRP Project 02-03, PI: David Nelson eling System that accurately reflects the distribution (, 978-663-9500). of thrusts used by aircraft at airports. Factors such as airport congestion, ambient conditions, and any IX. PROCESS USED TO DEVELOP PROBLEM effects of overall class of aircraft should be parame- STATEMENT terized for simple implementation. The knowledge ACRP Project 02-03 gained from this research will greatly improve the accuracy of emissions inventories. X. DATE AND SUBMITTED BY ACRP Project 02-03, December 20, 2007, PI: David IV. RESEARCH PROPOSED Nelson (, 978-663-9500). The development of the real-world thrust profile will require an analysis of recorded fuel flow rates, the recorded "N1" parameter or other electronic data from a statistically significant number of land- 9.2 Characterization of Operational ing, take-off cycles. The research will collect data Thrust Levels from cooperative aircraft operators and merge with AIRPORT COOPERATIVE RESEARCH other datasets generated via the airport or other PROGRAM PROBLEM STATEMENT sources. This program will develop operational thrust distributions to be used in conjunction with I. PROBLEM TITLE emissions profile. The research will investigate the Characterization of operational thrust levels influence of anticipated factors on the real-world thrust profile (e.g., LTO/hr). The research will iden- II. RESEARCH PROBLEM STATEMENT tify a simple approach to the parameterization of in- The International Civil Aviation Organization estab- use thrust levels. lished and maintains the databank of engine certifica- tion data for all engines currently in commercial V. ESTIMATE OF THE PROBLEM FUNDING aviation use. The emissions component of the AND RESEARCH PERIOD certification process defines four engine conditions Recommended Funding: $50,000 to $75,000 and the associated thrust levels: idle (7%); approach Research Period: 12 months (30%); climb-out (85%); and take-off (100%). Air- port emission inventories for CO, NOx, unburned VI. URGENCY AND PAYOFF POTENTIAL hydrocarbons (UHC), and "smoke number" are rou- This straightforward improvement to how invento- tinely constructed using the certification emission ries are constructed represents a very direct improve- indices, fuel flow rate, and time-in-mode data. While ment to emissions management and understanding. the overall time-in-mode is often known to some As alternative emission mitigation strategies emerge, degree, there is significant evidence that the four cer- particularly those that target the ground idle and tification thrust levels do not accurately mirror what taxiing phases, an improved tool is mandatory to is used during actual operation. Furthermore, emis- evaluate the benefits. This project would have a large sions profiles are nonlinear with engine thrust set- payoff to airport emissions management and air qual- tings. The emission rate of gas-phase HAPs at thrust ity modeling.