Deriving Benefits from Alternative Aircraft-Taxi Systems (2016)

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4This chapter introduces and describes the spreadsheet-based ATAM tool. The following bullet points provide an overview of each of the three sheets within the ATAM tool: • Instructions—This sheet provides an outline of how to use the tool. • ATAM—This sheet provides a traffic light matrix of the various benefits and issues associated with each of the five types of alternative aircraft-taxiing systems. In the tool, benefits are high- lighted in green, neutral issues in amber, and concerns in red. The summary information is linked to a pop-up discussion of each of the benefits and issues associated with alternative aircraft-taxiing systems. • Fuel and Emissions—This sheet provides an interactive tool that allows the user to enter different aircraft fleet mixes and taxiing times to assess potential overall fuel and emissions changes from ground-level fuel consumption for the three primary alternative aircraft-taxiing systems. Changes are based on use of aircraft main engines, APU, pushback tractors, and alternative aircraft-taxiing systems. The calculations use FAA’s Emissions and Dispersion Modeling System (EDMS) and an APU load factor from ACRP Report 64: Handbook for Evaluating Emissions and Costs of APUs and Alternative Systems. (Environmental Science Associates, 2012). 2.1 Instructions The ATAM tool can be found on the ACRP Project 02-50 web page (http://apps.trb.org/cmsfeed/ TRBNetProjectDisplay.asp?ProjectID=3696). Click on the ATAM.xlsx file to open the ATAM tool. When opened, the ATAM tool presents the Instructions sheet (see Figure 2), which contains details on how to use the tool. The hyperlinks (e.g., Go to ATAM) in the instructions allow the user to navigate between sheets, and the text next to each link provides an overview of each sheet. 2.2 ATAM The ATAM sheet contains a table of issues, benefits, and summary information associated with each type of alternative aircraft-taxiing system. The ATAM sheet (see Figure 3 for example) is linked to a pop-up discussion of each of the benefits and concerns associated with alternative aircraft-taxiing systems, which are also included in Appendix A. Within the ATAM, colors indicate whether a particular issue or benefit is considered a positive benefit (green), a negative impact (red), or neither (amber). If a mouse pointer is used to hover over a cell within the ATAM, a more detailed description of the particular issue or benefit will pop up. C H A P T E R 2 Alternative Taxiing Assessment Matrix (ATAM)

Alternative Taxiing Assessment Matrix (ATAM) 5 Figure 3. Sample page from the ATAM. 2.3 Fuel and Emissions The Fuel and Emissions sheet allows the user to enter an aircraft fleet mix and average or typical taxiing times (see Figure 4). The fleet mix can be for any time period as it is only used to derive the relative proportions; the aircraft size designations are based on EDMS. Once the aircraft fleet mix and taxiing times have been entered, the tool graphs the estimated fuel use, NOx (nitrogen oxide), and PM10 emissions impacts for that mix for the three primary alternative aircraft-taxiing systems (nose-wheel electric motor, main-wheel electric motor, and hybrid external large tractor; other systems could not be modeled due to lack of data). For com- parison purposes, the original ACRP Project 02-50 results are shown (in red in the ATAM tool), and those for the user-entered data (in blue in the tool), with the lines representing the range of calculated values. Figure 2. Instruction sheet for the ATAM.

6 Deriving Benefits from Alternative Aircraft-Taxi Systems Figure 4. Fuel and Emissions sheet.