The abbreviations used in this part have the following meanings in both upper and lower case:

CO2 Carbon dioxideCO Carbon monoxideEPA United States Environmental Protection Agency FAA Federal Aviation Administration, United States Department of Transportation g Gram(s)HC Hydrocarbon(s) HP Horsepower hr Hour(s) H20 waterkg Kilogram(s) kJ Kilojoule(s)kN Kilonewton(s)kW Kilowatt(s)lb Pound(s)LTO Landing and takeoff min Minute(s) NOX Oxides of nitrogenPa Pascal(s) rO Rated output rPR Rated pressure ratio sec Second(s) SP Shaft power SN Smoke number T Temperature, degrees Kelvin TIM Time in mode °C Degrees Celsius % Percent [Doc. No. 25613, 55 FR 32861, Aug. 10, 1990, as amended by Amdt. 34-3, 64 FR 5559, Feb. 3, 1999; Amdt. 34-5, 77 FR 76850, Dec. 31, 2012]