period independent of aircraft type based on the period the equipment usage.  The data inputs required to  estimate GSE emissions and the likely sources of obtaining this  information are listed in  Table A3-2  ( Data Inputs for Estimating Emissions from GSE ).  Table A3-2. Data Inputs for Estimating Emissions from GSE  Data Inputs  Conventional and Alternative Fuel  Description  Source  Equipment Type  Refers to the equipment  (e.g., baggage tug) and  fuel (e.g., diesel) type.  Site-specific GSE type information can be obtained from a variety of  sources including (but not limited to) the airport, the airlines, equipment/vehicle owner/operator, and in-the-field surveys.  If site-specific data is not available, default GSE equ ipment per aircraft type is provided in the FAA’s EDMS/AEDT model.  Usage  (hours per LTO  or hours per  year)  Refers to the hours of  use for a specific  equipment type either to  service one LTO of a  specific aircraft type or  for the entire inventory  period.  Site-specific GSE usage information can be obtained from a variety  of sources including (but not limited to) the airport, the airlines, the  equipment/vehicle owner/operator, and in-the-field surveys.  If site-specific data is not available, default aircra ft and airport GSE  usage data is provided in the FAA’s EDMS/AEDT model.  Size  (horsepower)  Brake horsepower (BHP)  refers to the average  rated brake horsepower  of an equipment type's  engine.  Site-specific GSE horsepower information can be variety of sources including (but not limited to) the airlines, the equipment/vehicle owner/operator, and in -the-field  surveys.  If site-specific data is not available, default aircraft and airport GSE  horsepower data is provided in the FAA’s EDMS /AEDT or EPA’s NONROAD models. Default data also may be available equipment manufacturers.  Load Factor  Refers to the average  operational horsepower  output of the engine  divided by its rated  horsepower.  Site-specific GSE load factor information can be obtained variety of sources including (but not limited to) the airlines, the equipment/vehicle owner/operator, and in -the-field  surveys.  If site-specific data is not available, default ai rcraft and airport GSE  load factor data is provided in the FAA’s EDMS /AEDT or EPA’s NONROAD models. Default data also may be available equipment manufacturers.  Emission Factor  Emission factors are  expressed in grams per  horsepower-hour, which  is specific to a given  engine size and fuel type.  Default emission factors for both aircraft and airport provided in FAA’s EDMS/AEDT model or may be estimated using  EPA’s NONROAD model.  Source: TRB, ACRP Report 78,  Airport Ground Support Equipment (GSE): Emission Reduction Strategies, Inventory, and  Tutorial , 2012; FAA,  Emissions and Dispersion Modeling System (EDMS) User’s Manual,  [FAA-AEE-07-01 (Rev. 10 –  06/07/13)], June 2013,  http://www.faa.gov/about/office_org/headquarters_offices/apl/research/models/edms_model/media/EDMS_5.1.4_User_Manual  .pdf; and EPA,  User’s Guide for the Final NONROAD2005 Model , December 2005, [EPA-420-R-05-013],  16$_{ }$ A3.2.1  Data Inputs  APPENDIX A3$_{ }$