{"data":{"id":"us/14-cfr-34.1","jurisdiction":"us","citation":"14 CFR 34.1","heading":"Definitions.","body":"As used in this part, all terms not defined herein shall have the meaning given them in the Clean Air Act, as amended (42 U.S.C. 7401 et. seq.):\nAct means the Clean Air Act, as amended (42 U.S.C. 7401 et. seq.).\nAdministrator means the Administrator of the Federal Aviation Administration or any person to whom he has delegated his authority in the matter concerned.\nAdministrator of the EPA means the Administrator of the Environmental Protection Agency and any other officer or employee of the Environmental Protection Agency to whom the authority involved may be delegated.\nAircraft as used in this part means any airplane as defined in 14 CFR part 1 for which a U.S. standard airworthiness certificate or equivalent foreign airworthiness certificate is issued.\nAircraft engine means a propulsion engine which is installed in, or which is manufactured for installation in, an aircraft.\nAircraft gas turbine engine means a turboprop, turbofan, or turbojet aircraft engine.\nCharacteristic level has the meaning given in Appendix 6 of ICAO Annex 16 as of July 2008 (incorporated by reference, see § 34.4). The characteristic level is a calculated emission level for each pollutant based on a statistical assessment of measured emissions from multiple tests.\nClass TP means all aircraft turboprop engines.\nClass TF means all turbofan or turbojet aircraft engines or aircraft engines designed for applications that otherwise would have been fulfilled by turbojet and turbofan engines except engines of class T3, T8, and TSS.\nClass T3 means all aircraft gas turbine engines of the JT3D model family.\nClass T8 means all aircraft gas turbine engines of the JT8D model family.\nClass TSS means all aircraft gas turbine engines employed for propulsion of aircraft designed to operate at supersonic flight speeds.\nCommercial aircraft engine means any aircraft engine used or intended for use by an “air carrier” (including those engaged in “intrastate air transportation”) or a “commercial operator” (including those engaged in “intrastate air transportation”) as these terms are defined in Title 49 of the United States Code and Title 14 of the Code of Federal Regulations.\nCommercial aircraft gas turbine engine means a turboprop, turbofan, or turbojet commercial aircraft engine.\nDate of manufacture of an engine is the date the inspection acceptance records reflect that the engine is complete and meets the FAA approved type design.\nDerivative engine for emissions certification purposes means an engine that is similar in design to an engine that has demonstrated compliance with the applicable exhaust emission standards of this part, as determined by the FAA, and has a U.S. type certificate issued in accordance with part 33 of this chapter.\nEmission measurement system means all of the equipment necessary to transport the emission sample and measure the level of emissions. This includes the sample system and the instrumentation system.\nEngine model means all commercial aircraft turbine engines which are of the same general series, displacement, and design characteristics and are approved under the same type certificate.\nExcepted, as used in § 34.9, means an engine that may be produced and sold that does not meet otherwise applicable standards. Excepted engines must conform to regulatory conditions specified for an exception in § 34.9. Excepted engines are subject to the standards of this part even though they are not required to comply with the otherwise applicable requirements. Engines excepted with respect to certain standards must comply with other standards from which they are not specifically excepted.\nExempt means an engine that does not meet certain applicable standards but may be produced and sold under the terms allowed by a grant of exemption issued pursuant to § 34.7 of this part and part 11 of this chapter. Exempted engines must conform to regulatory conditions specified in the exemption as well as other applicable regulations. Exempted engines are subject to the standards of this part even though they are not required to comply with the otherwise applicable requirements. Engines exempted with respect to certain standards must comply with other standards as a condition of the exemption.\nExhaust emissions means substances emitted into the atmosphere from the exhaust discharge nozzle of an aircraft or aircraft engine.\nIn-use aircraft gas turbine engine means an aircraft gas turbine engine which is in service.\nIntroduction date means the date of manufacture of the first individual production engine of a given engine model or engine type certificate family to be certificated. Neither test engines nor engines not placed into service affect this date.\nNew aircraft turbine engine means an aircraft gas turbine engine which has never been in service.\nNon-volatile particulate matter (nvPM) means emitted particles that remain at the exhaust nozzle exit plane of a gas turbine engine, and that did not volatilize after being heated to a temperature of at least 350 °C.\nPower setting means the power or thrust output of an engine in terms of kilonewtons thrust for turbojet and turbofan engines or shaft power in terms of kilowatts for turboprop engines.\nRated output (rO) means the maximum power/thrust available for takeoff at standard day conditions as approved for the engine by the Federal Aviation Administration, including reheat contribution where applicable, but excluding any contribution due to water injection, expressed in kilowatts or kilonewtons (as applicable), rounded to at least three significant figures.\nRated pressure ratio (rPR) means the ratio between the combustor inlet pressure and the engine inlet pressure achieved by an engine operation at rated output, rounded to at least three significant figures.\nReference day conditions means the reference ambient conditions to which the measured smoke, nvPM, and gaseous emissions must be corrected. The reference day conditions are as follows:\n(1) Temperature = 15 °C,\n(2) Specific humidity = 0.00634 kg H2O/kg of dry air, and\n(3) Pressure = 101.325 kPa\nSample system means the system which provides for the transportation of the gaseous emission sample from the sample probe to the inlet of the instrumentation system.\nShaft power means only the measured shaft power output of a turboprop engine.\nSmoke means the matter in exhaust emissions which obscures the transmission of light.\nSmoke number (SN) means the dimensionless term quantifying smoke emissions.\nStandard day conditions means the following ambient conditions: temperature = 15 °C, specific humidity = 0.00634 kg H2O/kg dry air, and pressure = 101.325 kPa.\nTaxi/idle (in) means those aircraft operations involving taxi and idle between the time of landing roll-out and final shutdown of all propulsion engines.\nTaxi/idle (out) means those aircraft operations involving taxi and idle between the time of initial starting of the propulsion engine(s) used for the taxi and the turn onto the duty runway.\nTier, as used in this part, is a designation related to the NOX emission standard for the engine as specified in § 34.21 or § 34.23 of this part (e.g., Tier 0).","path":["Title 14—Aeronautics and Space","CHAPTER I—FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION","SUBCHAPTER C—AIRCRAFT","PART 34—FUEL VENTING AND EXHAUST EMISSION REQUIREMENTS FOR TURBINE ENGINE POWERED AIRPLANES","Subpart A—General Provisions"],"source_url":"https://www.ecfr.gov/api/versioner/v1/full/2026-08-25/title-14.xml","current_through":"2026-08-25","vintage":"","retrieved_at":"2026-08-27T02:24:20Z","sha256":"217a08aea64790f9aa42c30072b0f3744d236c1ca6952be0b41c1272e857234d","source_id":"us-cfr","stale":true,"prev":"us/14-cfr-appendix-d-to-part-33","next":"us/14-cfr-34.2"},"notice":"GroundRules: Original legal text. Not legal advice."}