40 C.F.R. § 1030.105
The following definitions in this section apply to this part. Any terms not defined in this section have the meaning given in the Clean Air Act. The definitions follow:
Aircraft has the meaning given in 14 CFR 1.1 , a device that is used or intended to be used for flight in the air.
Aircraft engine means a propulsion engine that is installed on or that is manufactured for installation on an airplane for which certification under 14 CFR is sought.
Airplane has the meaning given in 14 CFR 1.1 , an engine-driven fixed-wing aircraft heavier than air, that is supported in flight by the dynamic reaction of the air against its wings.
Exempt means to allow, through a formal case-by-case process, an airplane to be certificated and operated that does not meet the applicable standards of this part.
Greenhouse Gas (GHG) means an air pollutant that is the aggregate group of six greenhouse gases: carbon dioxide, nitrous oxide, methane, hydrofluorocarbons, perfluorocarbons, and sulfur hexafluoride.
ICAO Annex 16, Volume III means Volume III of Annex 16 to the Convention on International Civil Aviation (see § 1030.110 ).
Maximum takeoff mass (MTOM) is the maximum allowable takeoff mass as stated in the approved certification basis for an airplane type design. Maximum takeoff mass is expressed in kilograms.
Performance model is an analytical tool (or a method) validated using corrected flight test data that can be used to determine the specific air range values for calculating the fuel efficiency metric value.
Reference geometric factor is a non-dimensional number derived from a two-dimensional projection of the fuselage.
Round has the meaning given in 40 CFR 1065.1001 .
Specific air range is the distance an airplane travels per unit of fuel consumed. Specific air range is expressed in kilometers per kilogram of fuel.
Subsonic means an airplane that has not been certificated under 14 CFR to exceed Mach 1 in normal operation.
Type certificated maximum passenger seating capacity means the maximum number of passenger seats that may be installed on an airplane as listed on its type certificate data sheet, regardless of the actual number of seats installed on an individual airplane.
40 C.F.R. §1030.105