Improving Ground Support Equipment Operational Data for Airport Emissions Modeling (2015)

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42 This chapter contains suggested practices and supporting data for computing airport GSE emissions inventories using updated default input parameters in place of those currently available. 5.1 Background Information Chapter 3 identified and described the principal tools for computing airport GSE emissions inventories. As discussed, the current (and most often used in North America) tool for comput- ing an airport GSE emissions inventory is the FAA’s EDMS. However, EDMS will be succeeded by FAA’s AEDT (Version 2b), which is scheduled to be released in 2015. It was further disclosed that within AEDT there are two methods (or options) for computing airport GSE emissions inventories: (1) Aircraft/Gate GSE Assignment Option and (2) GSE Population-Based Option. Each option has specific input parameters, most are the same (i.e., GSE type, operating time, etc.) but with some differences (i.e., the need to identify aircraft types, by model). Chapter 3 presented three alternative approaches for computing an inven- tory, basic, intermediate and advanced, each with a common set of fea- tures but differing from each other by their complexity, accuracy, and data requirements. Importantly, some of the “default” input data for computing airport GSE emissions inventories in AEDT are likely out-of-date and/or not necessarily representative of current conditions or reflective of individual airports. In par- ticular, the vehicles and equipment that constitute the default GSE fleet mix and their operating times (i.e., TIM) may be outmoded due to the changes in aircraft designs and/or GSE owner/operator operational practices. In response to this apparent shortcoming, Chapter 4 presented a protocol by which to collect airport GSE operational information to satisfy the AEDT GSE emissions inventory input data requirements. The suggested procedures are applicable to using the two available methods (i.e., aircraft/gate assign- ment or population based) and the three alternative approaches (i.e., basic, intermediate, advanced). Based upon the application of the GSE data collection protocol at a number of U.S. air- ports of varying size, function and location—combined with additional airport-related GSE data obtained from other studies—an updated set of default GSE operational data has been C H A P T E R 5 Modifying and Using Default GSE Emissions Model Data Reminder—Chapter 3, GSE Emis- sions Inventories, provides listings and explanation of the data requirements for computing GSE emissions inventories using three alternative approaches: Basic, Intermediate, and Advanced. Idea—As discussed in Chapter 6, coordination with airlines, cargo carriers and other airport ground support providers may enhance the quantity and quality of the GSE database for computing a GSE emissions inventory.

Modifying and Using Default GSE Emissions Model Data 43 developed. This chapter presents these data that are intended to be used in place of the default data currently in AEDT or in the event that airport-specific data cannot be collected due to time or resource constraints. 5.2 Redefining Default Data Among the assortment of default data contained in AEDT that are relied upon by model users to compute airport GSE emission inventories, some parameters characterize potentially greater degrees of influence on the results when compared to others. It is also acknowledged that the efforts and costs to substantiate the use of alternative default data can sometimes exceed the benefits. Therefore, the following GSE emissions inventory default data are suggested on the basis of their significance and ease of use. 5.2.1 GSE Fleet Mix and Operational Times Among the airport GSE default input parameters that are contained in AEDT for computing GSE emissions inventories, vehicle/equipment fleet mix and TIM are two of the most impor- tant. As discussed in Chapter 2, the vast majority of airport GSE are typically associated with the servicing of air carrier, cargo, and GA aircraft during the ground-based, airport turnaround process. These GSE comprise (but are not limited to) aircraft and baggage tractors, belt loaders, cabin service trucks, etc. And as defined in Chapter 3, the GSE operating times are the times the vehicle/equipment engines are on and generating emissions. 5.2.1.1 Passenger Aircraft Table 7 contains a listing of the current AEDT default GSE fleet mix for passenger aircraft, broken out by aircraft size (i.e., wide-, narrow-, and small-bodied). Also shown are the cor- responding “default” TIM for each GSE type presently contained in the models (i.e., Model Default TIM) for the aircrafts studied (i.e., the only aircrafts that were averaged from EDMS were aircrafts that were observed; only 340B, DH8D, and C402 were averaged for small-bodied aircraft EDMS defaults). Similarly, the airport GSE TIM specifically computed in support of this ACRP project are listed for comparative purposes (i.e., ACRP Project 02-46 TIM). These data sets reveal that in some cases, there are few to no differences in the GSE fleet mix and TIM between what is contained in AEDT and the results from the ACRP research. Wide- body cabin service/catering trucks and narrow-body aircraft tractors are two such examples. In other cases, the data show that there are variances in either the GSE fleet mix components, the TIM, or both when comparing the two data sets. The differences in the baggage tractor TIMs for wide-, narrow-, and small-body aircraft are notable examples as are the absences of air start units for wide- and narrow-body aircraft distinguished by the ACRP data. Based upon these findings, Table 7 also identifies the suggested default GSE fleet mix and their TIM to be used in AEDT for passenger aircraft. For ease of recognition, these vehicles/equipment and TIM are depicted in bold fonts. 5.2.1.2 Cargo Aircraft As discussed in connection with the passenger aircraft GSE default fleet mix and TIM, the same data sets for cargo aircraft are listed and compared in Table 8. Again, these data sets reveal that in some cases, there are few to no differences in the cargo air- craft GSE fleet mix and TIM between what is contained in AEDT and the results from the ACRP research. Wide-body aircraft tractors and belt loaders are two such examples. In other cases, Table 8 also shows that there are variances in either the GSE fleet mix components, the TIM, or

44 Improving Ground Support Equipment Operational Data for Airport Emissions Modeling GSE Fleet Mix Model De- fault TIM ACRP 02-46 TIM Proposed New De- fault TIM Wide-Body Aircraft Aircraft tractor 8 12 12 Baggage tractor*** 120 53 53*** Belt loader 35 42 42 Cabin service/catering truck* 28 28 28 Cargo/container loader 80 50 50 Lavatory truck 25 17 17 Air conditioner 30 NA - Air start 7 NA - APU*** 26 25 25*** Fuel/hydrant truck* 20 37 37 Service truck** 15 11 11 Water service 12 NA 5**** Narrow-Body Aircraft Aircraft tractor 7 7 7 Baggage tractor*** 61 28 28*** Belt loader 41 47 47 Cabin service/catering truck* 17 21 21 Air conditioner 30 41 41 Air start 7 NA - APU*** 26 15 15*** Fuel/hydrant truck* 14 17 17 GPU 40 35 35 Lavatory truck 14 8 8 Service truck** 14 9 9 Water service 12 5 5 Small-Body Aircraft Aircraft tractor 5 9 9 Baggage tractor*** 27 13 13 Belt loader 23 22 22 Cabin service/catering truck* 6 6 6 Fuel/hydrant truck* 20 9 9 GPU 40 35 35 Lavatory truck 0 4 4 Service truck** 11.5 NA - NA = Not Applicable. TIM = Operating Time-in-Mode. Bold font = suggested default GSE fleet mix and TIM. *Cabin service and catering trucks are separate in AEDT. Fuel and hydrant trucks are separate in EDMS. TIM represents average between the two. **Service Truck includes all service vehicles, including minivan. ***Gate-only observations. Final suggestion for baggage tractors is suggested to be higher (based on airport size) to account for the time it takes to travel to loading/unloading area. Final suggestion for APUs is sug- gested to be higher (based on airport size) to account for taxi-in and taxi-out times. ****Wide-bodied water service based on narrow-bodied aircraft. Table 7. Passenger aircraft GSE fleet mix and operating TIM.

Modifying and Using Default GSE Emissions Model Data 45 both when comparing the two data sets. For example, the replacement of baggage tractors with cargo tractors and air conditioners with GPUs are two notable changes. It is also noteworthy that the ACRP data also now cover narrow-body cargo aircraft GSE. Based upon these findings, Table 8 identifies the suggested cargo aircraft “default” GSE fleet mix and their TIM to be used in AEDT. Again, for ease of recognition, these vehicles/equipment and TIM are depicted in “bold” fonts. 5.2.1.3 TIM by Airport Size Airport size classifications were derived by means of operations per year. Table 9 lists the total number of airport operations in 2014 for each airport and its size classification. Airports with less than 100,000 total operations per the most recent calendar year (2014) were considered to be small- sized airports. Airports with 100,000–400,000 operations were considered to be medium-sized airports. Airports with more than 400,000 operations were considered to be large-sized airports. GSE TIMs were also classified by airport size (small, medium, or large-hub airport). The same methodology was used to calculate the proposed new default TIM. A weighted average of ACRP observations from this study, previous studies, and the study completed by KM Chng17 (KM Chng Environmental 2004) as was for the TIMs by aircraft size. GSE Fleet Mix Model Default TIM ACRP 02-46 TIM Proposed New De- fault TIM Wide-Body Aircraft Aircraft tractor 8 7 7 Belt loader 27 23 23 Cargo tractor*** 0 29 29*** Cargo/container loader* 73 91 91 Fuel/hydrant truck* 33 24 24 Lavatory truck 13 6 6 Service truck** 12 3 3 Air conditioner 23 NA - Air start 7 NA - Baggage tractor 90 NA - Cabin service 14 NA - Fork lift 0 NA - GPU 0 55 55 Water service 12 NA - Narrow-Body Aircraft Aircraft tractor 0 5 5 Belt loader 0 4 4 Cargo tractor*** 0 13 13*** Cargo/container loader 0 47 47 Fuel/hydrant truck 0 25 25 GPU 0 66 66 Other 0 11 11 NA = Not Applicable. TIM = Operating Time-in-Mode. Bold font = suggested default GSE fleet mix and TIM. *Fuel and hydrant trucks are separate in AEDT. TIM represents average between the two. **Service truck includes all service vehicles. ***Gate-only observations. Final suggestion for baggage tractors is suggested to be higher (based on airport size) to account for the time it takes to travel to loading/unloading area. Final suggestion for APUs is sug- gested to be higher (based on airport size) to account for taxi-in and taxi-out times. Table 8. Cargo aircraft GSE fleet mix and operating TIM.

46 Improving Ground Support Equipment Operational Data for Airport Emissions Modeling Passenger Aircraft: Small-Sized Airports. Passenger aircraft at small-sized airports are not able to be summarized, as only one small airport was included in GSE survey operations for this study. Furthermore, only narrow-bodied aircraft were able to be observed due to the limitations in aircraft operation turnaround scheduling. Passenger Aircraft: Medium-Sized Airports. Suggested TIMs for GSE supporting wide- body, narrow-body, and small-body aircraft were compiled by airport size based on the num- ber of total operations in the most recent calendar year (2014). Table 10 represents GSE TIMs by passenger aircraft size at medium-sized airports. The five airports that were classified as medium-sized were TPA, BOS, SAN, BWI, and PDX (see Table 9 for airport size classification). Passenger Aircraft: Large-Sized Airports. Table 11 represents GSE TIMs by passenger air- craft size at large-sized airports. The three airports that were classified as large-sized were MSP, ATL, and DFW (see Table 9 for airport size classification). Cargo Aircraft: Medium-Sized Airports. Cargo aircraft were only sampled at Oakland, CA (a medium-sized airport). See Table 9 for proposed suggestions of cargo aircraft GSE TIMs for a medium-sized airport. Cargo Aircraft: Large-Sized Airports. No cargo aircrafts were observed at large-sized air- ports for this study. However, the study completed by KM Chng19 at PHL did observe cargo aircrafts (narrow-bodied: B727; wide-bodied: A300, A310, DC10). Airport Number of Total Oper- ations in 2014 (thou- sands) * Airport Size PVD 75 Small TPA 184 Medium BOS 368 Medium SAN 191 Medium BWI 245 Medium PDX 216 Medium OAK** 204 Medium PHL*** 419 Large MSP 412 Large ATL 868 Large DFW 680 Large *Operations data were obtained from FAA’s Airport Operations and Ranking Reports using the Air Traffic Activity Data System (http://aspm.faa.gov/opsnet/sys/Main.asp?force=atads). **Cargo observations only. *** Study completed by KM Chng Environmental. GSE 2004 Survey Prepared for KBE in support of the PHL Capacity Enhancement Pro- gram Environmental Impact Statement. 2004. Table 9. Total airport operations in 2014 and size classification. 19 KM Chng Environmental. GSE 2004 Survey Prepared for KBE in support of the PHL Capacity Enhancement Program Environmental Impact Statement. 2004.

Modifying and Using Default GSE Emissions Model Data 47 GSE Fleet Mix Model De- fault TIM ACRP 02-46 TIM Proposed New De- fault TIM Wide-Body Aircraft Aircraft tractor 8 7 7 Baggage tractor*** 120 30*** 35 Belt loader 35 82 82 Cabin service/catering truck* 28 33 33 Cargo/container loader 80 NA - Lavatory truck 25 NA - Air conditioner 30 NA - Air start 7 NA - APU*** 26 52*** 57 Fuel/hydrant truck* 20 24 24 Service truck** 15 15 15 Water service 12 NA - Narrow-Body Aircraft Aircraft tractor 7 6 6 Baggage tractor*** 61 25*** 30 Belt loader 41 52 52 Cabin service/catering truck* 17 24 24 Air conditioner 30 41 41 Air start 7 NA - APU*** 26 16*** 21 Fuel/hydrant truck* 14 17 17 GPU 40 34 34 Lavatory truck 14 7 7 Service truck** 14 10 10 Water service 12 5 5 Small-Body Aircraft Aircraft tractor 5 6 6 Baggage tractor*** 27 8*** 13 Belt loader 23 36 36 Cabin service/catering truck* 6 NA - Fuel/hydrant truck* 20 6 6 GPU 40 27 27 Lavatory truck 0 2 2 Service truck** 11.5 NA - NA = Not Applicable. TIM = Operating Time-in-Mode. Bold font = suggested default GSE fleet mix and TIM. *Cabin service and catering trucks are separate in AEDT. Fuel and hydrant trucks are separate in AEDT. TIM represents average between the two. **Service truck includes all service vehicles, including minivan. ***Gate-only observations. Final suggestion for baggage tractors is higher (based on airport size) to account for the time it takes to travel to loading/unloading area. Final suggestion for APUs is higher (based on air- port size) to account for taxi-in and taxi-out times. Table 10. Proposed new default TIM for passenger aircraft GSE fleet mix for medium-sized airports.

48 Improving Ground Support Equipment Operational Data for Airport Emissions Modeling GSE Fleet Mix Model De- fault TIM ACRP 02-46 TIM Proposed New De- fault TIM Wide-Body Aircraft Aircraft tractor 8 12 12 Baggage tractor*** 120 55*** 62 Belt loader 35 40 40 Cabin service/catering truck* 28 68 68 Cargo/container loader 80 50 50 Lavatory truck 25 8 8 Air conditioner 30 NA - Air start 7 NA - APU*** 26 18*** 23 Fuel/hydrant truck* 20 38 38 Service truck** 15 4 4 Water service 12 NA - Narrow-Body Aircraft Aircraft tractor 7 7 7 Baggage tractor*** 61 32*** 39 Belt loader 41 44 44 Cabin service/catering truck* 17 19 19 Air conditioner 30 NA - Air start 7 NA - APU*** 26 15*** 22 Fuel/hydrant truck* 14 17 17 GPU 40 44 44 Lavatory truck 14 10 10 Service truck** 14 9 9 Water service 12 NA - Small-Body Aircraft (KM Chng Study only) Aircraft tractor 5 9 9 Baggage tractor*** 27 23*** 30 Belt loader 23 20 20 Cabin service/catering truck* 6 6 6 Fuel/hydrant truck* 20 11 11 GPU 40 35 35 Lavatory truck 0 4 4 Service truck** 11.5 NA - NA = Not Applicable. TIM = Operating Time-in-Mode. Bold font = suggested default GSE fleet mix and TIM. *Cabin service and catering trucks are separate in AEDT. Fuel and hydrant trucks are separate in AEDT. TIM represents average between the two. **Service truck includes all service vehicles, including minivan. ***Gate-only observations. Final suggestion for baggage tractors is higher (based on airport size) to account for the time it takes to travel to loading/unloading area. Final suggestion for APUs is higher (based on air- port size) to account for taxi-in and taxi-out times. Table 11. Proposed new default TIM for passenger aircraft GSE fleet mix for large-sized airports.

Modifying and Using Default GSE Emissions Model Data 49 5.2.1.4 Non-Gate GSE Operating Times There are some types of GSE that also operate while away from the gate when traveling between gates or between gates and the terminal. These GSE mainly comprise baggage/cargo tugs, cabin service/catering/lavatory trucks, and fuel trucks. As a means of accounting for these GSE operational times away from the gates and their resultant emissions, the approximate travel distances between the centroids of several airport terminals and the airside gates, fuel facilities, and cargo areas were measured. Table 12 presents the approximate distances at each of the airports sampled for this project. From this, average Airport Size Terminal Distance (miles) MSP #1 L 1 0.1 MSP #1 L 2 0.33 MSP #1 L 3 0.3 MSP #1 L 4 0.25 MSP #2 L 1 0.1 ATL L 1 0.29 ATL L 2 0.49 ATL L 3 0.67 ATL L 4 0.86 ATL L 5 1.08 DFW L 1 0.15 DFW L 2 0.15 DFW L 3 0.15 DFW L 4 0.15 DFW L 5 0.15 TPA M 1 0.24 TPA M 2 0.25 TPA M 3 0.17 TPA M 4 0.27 TPA M 5 0.28 BOS M 1 0.25 BOS M 2 0.26 BOS M 3 0.25 BOS M 4 0.24 BOS M 5 0.4 BOS M 6 0.31 BOS M 7 0.15 SAN M 1 0.14 SAN M 2 0.19 SAN M 3 0.34 SAN M 4 0.45 BWI M 1 0.22 BWI M 2 0.18 BWI M 3 0.16 BWI M 4 0.2 BWI M 5 0.26 BWI M 6 0.23 PDX M 1 0.26 PDX M 2 0.21 PVD S 1 0.22 Table 12. Airport distances from terminal to gate.

50 Improving Ground Support Equipment Operational Data for Airport Emissions Modeling distances were computed grouped by airport size (small, medium, or large). Average distances from each terminal to the baggage claim area were measured. From these average distances by airport size, an average TIM was estimated (Table 13). Table 13 provides some surrogate (or default) values for use in the absence of airport-specific TIM measured values. Using an estimated speed of 20 mph, these data were developed by mea- suring the approximate travel distances between the centroids of several airport terminals and the airside gates, fuel facilities, and cargo areas. As shown, these TIM data are provided for large- and medium/small sized airports, are sug- gested to be additive to the TIMs when the GSE are at the gates, and are only applicable to those GSE that are expected to travel outside the aircraft service area. 5.2.1.5 Deicing Operating Times Presently, AEDT does not include operating times for GSE deicing vehicles. These specially designed GSE are equipped with booms or cherry pickers that are used to store, transport, heat, and spray deicing fluid on an aircraft exterior to reduce and/or eliminate ice and snow prior to departure. At the request of the ACRP Project 02-46 panel, the research team submitted a plan to sample deicing activities in advance of delivering this protocol, to the end of being able to acquire data prior to the termination of the 2013–2014 deicing season (if determined cost reasonable and via- ble) and fulfill the ACRP 02-46 research objectives outlined in the amplified work plan (AWP). After consideration the research team proposed that field sampling of deicing activities is not the ideal approach for data collection within ACRP Project 02-46 for the following reasons: • Safety and security: There are safety considerations related to being at or near aircraft and equipment movement areas during inclement weather conditions; further, air traffic control or other parties within the boundary of responsibility may restrict access for safety reasons. • Logistics: The logistical planning of a field survey during a deicing event is hampered by (1) being able to reliably monitor interested airports’ meteorological conditions to predict a good sampling time; (2) cost-effectively moving personnel to the desired airport in time to establish field presence and implement the sampling; and (3) having airport escort personnel available on relatively short notice in poor ambient conditions. • Vantage point limitations: The only viable approach to sample (if safety, security, and logistics considerations allow sampling) is the windshield survey where observations are made while the research team remains in an escort vehicle. Limitations to this approach include a signifi- cant opportunity to miss equipment activities on all sides of the aircraft, as well as reduced visibility in the event domain due to precipitation. As a means of accounting for these GSE operational times and their resultant emissions, the research team observed several video logs of complete deicing procedures at a variety of airports. The seasonal dependency of collecting deicing observations as well as the limited constraints on accessing a restricted area prevented the research team from collecting deicing observations. As a result, video observations were determined to be the best resource for compiling deicing observations. A complete list of deicing video log details are provided in Table 14. Airport Size Average Distance (miles) Average TIM (minutes) Large 0.34 6.8 Medium 0.25 5 Small 0.22 4.4 Table 13. Non-gate GSE operating times.

Modifying and Using Default GSE Emissions Model Data 51 As a means of accounting for deicing GSE operational times and their resultant emissions, Table 15 provides some default deicing TIM values for use in the absence of airport-specific values. These data were derived by observing aircraft deicing activities recorded on video (see Table 14) and averaging the TIM by aircraft size. TIM data are provided for wide- and narrow/small-body aircraft and are suggested to be considered representative of the times to de-ice each aircraft. 5.2.2 GSE Population-Based Fleet Size and Mix As discussed in Chapter 3, one of the two available methods for computing GSE emission inventories in AEDT is the GSE population-based option. Under this option, the entire airport GSE fleet is input to the models by GSE type (e.g., baggage tug) and total number (i.e., 100 units). In cases where data cannot be obtained through GSE owner/operator/provider records or through in-the-field surveys, this chapter describes a method by which these data may be estimated and used in substitution or as default data to compute the GSE emissions inventory. Notably, this method was derived as part of the ACRP Report 78 research and is based upon the collection and assessment of GSE population data at several airports located across the United States of varying sizes, operational levels, climates, and GSE populations. Aircraft Type AEDT Category Airline Airport # Trucks Spray Time Limited View Other Comments CRJ9 LCJP USA IND 2 6.00 No Good, complete vid- eo. Lost track of 2nd truck at end. A320/321 LCJP JetBlue JFK 4 2.33 No Starts at 5:20. B737 LCJP DAL DTW 2 8.95 No Originally 1 row for 2 records (8:57 and 6:57) B737 LCJP DAL DTW 2 6.95 No Originally 1 row for 2 records (8:57 and 6:57) A310 HCJP FDX IND 4 3.48 No Originally 1 line for 4 records; split into 4 lines (3:29 (x2), 4:49, 6:22); The low time was for the two trucks deicing the tail, the longer times were for the two de- icing the wings. A310 HCJP FDX IND 4 3.48 No A310 HCJP FDX IND 4 4.82 No A310 HCJP FDX IND 4 6.37 No Table 14. Deicing video log details. Aircraft Size Average Number of Trucks Average TIM (minutes) Wide-Body 4 4.5 Narrow- & Small-Body 2.5 6 Table 15. Deicing GSE operating times.

52 Improving Ground Support Equipment Operational Data for Airport Emissions Modeling An airport’s GSE fleet size and make-up can be estimated using this method from the number of annual commercial aircraft operations at the airport. Figure 19, from ACRP Report 78, provides the computed relationships between commercial aircraft operations and the corresponding GSE fleet size at the study airports. For example, an air- port with 100,000 annual operations is shown to have a total GSE fleet of approximately 500 units (i.e., vehicles/equipment). As discussed, this is a proxy and not to be taken as the actual size of the example airport’s GSE fleet. As shown in Table 16 (also from ACRP Report 78), the make-up (i.e., fleet mix) of an airport GSE fleet is characteristically comprised of 23.6% baggage/cargo tugs, 9.7% belt loaders, 1.4% lavatory trucks, etc. Again, this fleet composition is based on surveys of several airports of varying size, operational levels, etc., but is considered to be a good representation of most U.S. airports. Using an airport with 100,000 annual operations as an example of the surrogate fleet of 500 airport-wide GSE derived from Figure 19, roughly 23.6% (or 118) are expected to be baggage/cargo tugs, 9.7% (or 48) are belt loaders, and 1.4% (or 7) are lavatory trucks. These data can then be input to AEDT to aid in computing an airport GSE emissions inventory. 5.2.3 Non-Gate GSE Operating Times The data and information provided in Section 5.2.1 addresses the GSE operating times (or TIM) when the GSE are at, or in the vicinity of, the aircraft gate. However, there are some types of GSE that also operate while away from the gate when traveling between gates or between gates and the terminal. These GSE mainly comprise baggage/cargo tugs, cabin service/catering/lavatory trucks, and fuel trucks. 100,000 1,000 1,500 – 500 2,000 2,500 – 200,000 Surveyed Inventory Esmated Inventory 300,000 2010 Commercial Operaons To ta l G SE In ve nt or y 400,000 500,000 600,000 700,000 Source: ACRP Report 78: Airport Ground Support Equipment (GSE): Emission Reducon Strategies, Inventory, and Tutorial, 2012. Figure 19. Airport operations versus total GSE.

Modifying and Using Default GSE Emissions Model Data 53 As a means of accounting for these GSE operational times away from the gates and their resul- tant emissions, Table 17 provides some surrogate (or default) values for use in the absence of airport-specific TIM measured values. The data were developed by measuring the approximate travel distances between the centroids of several airport terminals and the airside gates, fuel facilities, and cargo areas. These TIM data are provided for large- and medium/small sized airports and should be addi- tive to the TIMs when the GSE are at the gates and are only applicable to those GSE that are expected to travel outside the aircraft service area. 5.2.4 Deicing GSE Operating Times Presently, AEDT does not include operating times for GSE deicing vehicles. As discussed in Chapter 2, these specially designed GSE are equipped with booms or cherry pickers that are used to store, transport, heat, and spray deicing fluid on an aircraft exterior to reduce and/or eliminate ice and snow prior to departure. GSE Type % of Fleet Baggage tugs/cargo tugs 23.6 Cars/pickups/vans/suvs 12.4 Other 9.8 Belt loaders 9.7 Aircraft tractor/tugs 7.3 Deicing trucks 5.3 Fork lifts 4.7 Lifts 4.6 Cabin service/catering trucks 4.1 Air conditioners/heaters 3.9 Carts 3.9 Generators/GPUs/GPU-ACs 2.5 Cargo loaders 1.8 Lavatory trucks 1.4 Fuel trucks 1.4 Hydrant trucks 1.1 Passenger stairs 1.0 Maintenance trucks 0.6 Air start units 0.5 Light carts/light stands 0.4 Buses 0.1 Total 100 Table 16. Airport GSE fleet mix composition. Airport Size Average Distance (miles) Average TIM (minutes) Large 0.34 6.8 Medium 0.25 5 Small 0.22 4.4 Table 17. Non-gate GSE operating times.

54 Improving Ground Support Equipment Operational Data for Airport Emissions Modeling As a means of accounting for these GSE operational times and their resultant emissions, Table 18 provides some default TIM values for use in the absence of airport-specific values. These data were derived by observing aircraft deicing activities recorded on video. As shown, these TIM data are provided for wide- and narrow/small-body aircraft and should be considered representative of the times to deice each aircraft. 5.2.5 GSE Engine Load Factors The GSE engine load factor is an approximate measure of the engine power setting, expressed as a percentage ranging from 0% to 100%. In other words, an engine operating at maximum full power has a 100% load factor and a nonoperating engine has a load factor of 0%. Because of various design and operational considerations, most fossil-fueled engines operate at something measurably less than full power. For the purposes of providing up-to-date default GSE engine load factor data for use in AEDT, Table 19 contains a listing of alternative values, by GSE type. These load factors were Aircraft Size Average Number of Trucks Average TIM (minutes) Wide-Body 4 4.5 Narrow- & Small-Body 2.5 6 Table 18. Deicing GSE operating times. Equipment Type NESCAUM CARB ICAO AEDT Average Air conditioner 0.39 -- 0.50 0.75 0.55 Air start 0.02 -- 0.50 0.90 0.47 Aircraft tractor 0.12 0.54 0.25 0.80 0.43 Baggage tractor 0.02 0.37 0.50 0.55 0.36 Belt loader 0.07 0.34 0.25 0.50 0.29 Bobtail -- 0.37 0.25 0.55 0.39 Cabin service truck -- -- 0.25 0.53 0.39 Cargo loader 0.06 0.34 0.25 0.50 0.29 Cargo tractor -- 0.36 0.25 0.54 0.38 Cart -- -- -- 0.50 0.50 Catering truck -- -- 0.25 0.53 0.39 Deicer 0.07 -- 0.60 0.95 0.54 Fork lift 0.09 0.2 0.25 0.30 0.21 Fuel truck 0.08 -- 0.50 0.25 0.28 Generator -- -- -- 0.82 0.82 GPU 0.1 -- 0.50 0.75 0.45 Hydrant cart -- -- -- 0.70 0.70 Hydrant truck -- -- 0.50 0.70 0.60 Lavatory truck 0.14 -- 0.25 0.25 0.21 Lift 0.27 0.34 0.25 0.50 0.34 Other -- 0.34 -- 0.50 0.42 Passenger stand 0.07 0.4 0.25 0.57 0.32 Service truck 0.09 -- 0.25 0.20 0.18 Sweeper -- -- -- 0.51 0.51 Water service -- -- 0.25 0.20 0.23 Table 19. GSE engine load factors.

Modifying and Using Default GSE Emissions Model Data 55 derived from a composite of data presently contained in AEDT (default values), supplemented with data obtained from other sources including CARB, NESCAUM, and ICAO. As shown, the values range from 18% to 82%, depending on the GSE type, and should be recognized as average conditions. 5.2.6 GSE Fuel Types The majority of airport GSE are still mainly powered by gasoline and diesel engines, but this trend is changing with the recent and growing emergence of electric-powered and alternatively fueled GSE. Presently, AEDT accounts for and computes emissions from GSE burning gasoline and diesel. It is assumed that electric-powered GSE generate no emissions. ACRP Report 78 included an assessment of GSE fuel type data at several airports of varying sizes, operational levels, climates, and GSE populations located across the United States. These data were further supplemented with similar data obtained from other participating GSE owners/ operators/providers. From this assessment, Table 20 contains a listing of GSE fuel types segre- gated by GSE type. In the absence of airport-specific GSE fuel type data, these data can be input to AEDT as defaults to aid in computing an airport GSE emissions inventory. GSE Type Fuel/Power Type (%) Diesel Gasoline Electric Air start 95.9 3.3 0.8 Aircraft tractor 77.8 9.4 12.8 Baggage tractor 18.2 62.1 19.7 Belt loader 29.7 52.9 17.4 Cabin service truck 77.0 22.6 0.4 Cargo loader 90.9 8.7 0.5 Catering truck 77.0 22.6 0.4 Fuel truck 86.0 11.4 2.6 GPU 78.1 9.2 0.0 Hydrant truck 73.1 26.9 0.0 Lavatory truck 20.5 70.2 9.3 Service truck 39.1 60.9 0.0 Source: ACRP Report 78: Airport Ground Support Equipment (GSE): Emission Reduction Strategies, Inventory, and Tutorial, 2012. Table 20. Fuel mix as reported in ACRP Report 78.