FEDERAL AVIATION REGULATIONS PART 1 DEFINITIONS AND ABBREVIATIONS 1.1 GENERAL DEFINITIONS As used in Subchapters A through K of this chapter unless the context requires otherwise: "Administrator" means the Federal Aviation Administrator or any person to whom he has delegated his authority in the matter concerned. "Aerodynamic coefficients" means nondimensional coefficients for aerodynamic forces and moments. "Air carrier" means a person who undertakes directly by lease, or other arrangement, to engage in air transportation. "Air commerce" means interstate, overseas, or foreign air commerce or the transportation of mail by aircraft or any operation or navigation of aircraft within the limits of any Federal airway or any operation or navigation of aircraft which directly affects, or which may endanger safety in, interstate, overseas, or foreign air commerce. "Aircraft" means a device that is used or intended to be used for flight in the air. "Aircraft engine" means an engine that is used or intended to be used for propelling aircraft. It includes turbosuperchargers, appurtenances, and accessories necessary for its functioning, but does not include propellers. "Airframe" means the fuselage, booms, nacelles, cowlings, fairings, airfoil surfaces (including rotors but excluding propellers and rotating airfoils of engines), and landing gear of an aircraft and their accessories and controls. "Airplane" means an engine-driven fixed-wing aircraft heavier than air, that is supported in flight by the dynamic reaction of the air against its wings. "Airport" means an area of land or water that is used or intended to be used for the landing and takeoff of aircraft, and includes its buildings and facilities, if any. "Airport traffic area" means, unless otherwise specifically designated in Part 93, that airspace within a horizontal radius of 5 statute miles from the geographical center of any airport at which a control tower is operating, extending from the surface up to, but not including, an altitude of 3,000 feet above the elevation of the airport. "Airship" means an engine-driven lighter-than-air aircraft that can be steered. "Air traffic" means aircraft operating in the air or on an airport surface, exclusive of loading ramps and parking areas. "Air traffic clearance" means an authorization by air traffic control, for the purpose of preventing collision between known aircraft, for an aircraft to proceed under specified traffic conditions within controlled airspace. "Air traffic control" means a service operated by appropriate authority to promote the safe, orderly, and expeditious flow of air traffic. "Air transportation" means interstate, overseas, or foreign air transportation or the transportation of mail by aircraft. "Alternate airport" means an airport at which an aircraft may land if a landing at the intended airport becomes inadvisable. "Altitude engine" means a reciprocating aircraft engine having a rated takeoff power that is producible from sea level to an established higher altitude. "Appliance" means any instrument, mechanism, equipment, part, apparatus, appurtenance, or accessory, including communications equipment, that is used or intended to be used in operating or controlling an aircraft in flight, is installed in or attached to the aircraft, and is not part of an airframe, engine, or propeller. "Approved" unless used with reference to another person, means approved by the Administrator. "Area navigation (RNAV)" means a method of navigation that permits aircraft operations on any desired course within the coverage of station-referenced navigation signals or within the limits of self-contained system capability. "Area navigation high route" means an area navigation route within the airspace extending upward from, and including 18,000 MSL to flight level 450. "Area navigation low route" means an area navigation route within the airspace extending upward from 1,200 feet above the surface of the earth to, but not including 18,000 feet MSL. "Armed Forces" means the Army, Navy, Air Force, Marine Corps, and Coast Guard, including their regular and reserve components and members serving without component status. "Autorotation" means a rotorcraft flight condition in which the lifting rotor is driven entirely by action of the air when the rotorcraft is in motion. "Auxiliary rotor" means a rotor that serves either to counteract the effect of the main rotor torque on a rotorcraft or to maneuver the rotorcraft about one or more of its three principal axes. "Balloon" means a lighter-than-air aircraft that is not engine-driven. "Brake horsepower" means the power delivered at the propeller shaft (main drive or main output) of an aircraft engine. "Calibrated airspeed" means indicated airspeed of an aircraft, corrected for position and instrument error. Calibrated airspeed is equal to true airspeed in standard atmosphere at sea level. "Category" - (1) As used with respect to the certification, ratings, privileges, and limitations of airmen, means a broad classification of aircraft. Examples include: airplane; rotorcraft; glider; and lighter-than-air; and (2) As used with respect to the certification of aircraft, means a grouping of aircraft based upon intended use or operating limitations. Examples include: transport; normal; utility; acrobatic; limited; restricted; and provisional. "Category II operations," with respect to the operation of aircraft, means a straight-in ILS approach to the runway of an airport under a Category II ILS instrument approach procedure issued by the Administrator or other appropriate authority. "Category III operations," with respect to the operation of aircraft, means a straight-in ILS approach to the runway of an airport under a Category III ILS instrument approach procedure issued by the Administrator or other appropriate authority. "Category A," with respect to transport category rotorcraft, means multiengine rotorcraft designed with engine and system isolation features specified in Part 29 and utilizing scheduled takeoff and landing operations under a critical engine failure concept which assures adequate designated surface area and adequate performance capability for continued safe flight in the event of engine failure. "Category B," with respect to transport category rotorcraft, means single-engine or multiengine rotorcraft which do not fully meet all Category A standards. Category B rotorcraft have no guaranteed stay-up capability in the event of engine failure and unscheduled landing is assumed. "Ceiling" means the height above the earth's surface of the lowest layer of clouds or obscuring phenomena that is reported as "broken," "overcast," or "obscuration" and not classified as "thin" or "partial." "Civil aircraft" means aircraft other than public aircraft. "Class" - (1) As used with respect to the certification, ratings and privileges of airmen, means a classification of aircraft within a category having similar operating characteristics. Examples include: single engine; multiengine; land; water; gyroplane; helicopter; airship; and free balloon; and (2) As used with respect to the certification of aircraft, means a broad grouping of aircraft having similar characteristics of propulsion, flight or landing. Examples include: airplane; rotorcraft; glider; balloon; landplane and seaplane. "Clearway" means: (1) For turbine engine powered airplanes certified after August 29, 1959, an area beyond the runway, not less than 500 feet wide, centrally located about the extended centerline of the runway, and under the control of the airport authorities. The clearway is expressed in terms of a clearway plane, extending form the end of the runway with an upward slope not exceeding 1.25 percent, above which no object nor any terrain protrudes. However, threshold lights may protrude above the plane if their height above the runway is 26 inches or less and if they are located to each side of the runway. (2) For turbine engine powered airplanes certificated after September 30, 1958, but before August 29, 1959, an area beyond the takeoff runway extending no less than 300 feet on either side of the extended centerline of the runway, at an elevation no higher than the elevation of the end of the runway, clear of all fixed obstacles, and under the control of the airport authorities. "Climbout speed," with respect to rotorcraft means a referenced airspeed which results in a flight path clear of the height-velocity envelope during initial climbout. "Commercial operator" means a person who, for compensation or hire, engages in the carriage by aircraft in air commerce of persons or property, other than as an air carrier or foreign air carrier or under the authority of Part 375 of this Title. Where it is doubtful that an operation is for "compensation or hire," the test applied is whether the carriage by air is merely incidental to the person's other business or is, in itself, a major enterprise for profit. "Controlled airspace" means airspace, designated as continental control area, control area, control zone, terminal control area, or transition area, within which some or all aircraft may be subject to air traffic control. "Crewmember" means a person assigned to perform duty in an aircraft during flight time. "Critical altitude" means the maximum altitude at which, in standard atmosphere, it is possible to maintain, at a specified rotational speed, a specified power or a specified manifold pressure. Unless otherwise stated, the critical altitude is the maximum altitude at which it is possible to maintain, at the maximum continuous rotational speed, one of the following: (1) The maximum continuous power, in the case of engines for which this power rating is the same at sea level and at the rated altitude. (2) The maximum continuous rated manifold pressure, in the case of engines, the maximum continuous power of which is governed by a constant manifold pressure. "Critical engine" means the engine whose failure would most adversely affect the performance or handling qualities of an aircraft. "Decision height," with respect to the operation of aircraft, means the height at which a decision must be made, during an ILS or PAR instrument approach, to either continue the approach or to execute a missed approach. "Equivalent airspeed" means the calibrated airspeed of an aircraft corrected for adiabatic compressible flow for the particular altitude. Equivalent airspeed is equal to calibrated airspeed in standard atmosphere at sea level. "Extended over-water operation" means- (1) With respect to aircraft other than helicopters, an operation over water at a horizontal distance of more than 50 nautical miles from the nearest shoreline; and (2) With respect to helicopters, and operation over water at a horizontal distance of more than 50 nautical miles from the nearest shoreline and more than 50 nautical miles from an off-shore heliport structure. "External load" means a load that is carried, or extends, outside of the aircraft fuselage. "External-load attaching means" means the structural components used to attach an external load to an aircraft, including external-load containers, the backup structure at the attachment points, and any quick-release device used to jettison the external load. "Fireproof" - (1) With respect to materials and parts used to confine fire in a designated fire zone, means the capacity to withstand at least as well as steel in dimensions appropriate for the purpose for which they are used, the heat produced when there is a severe fire of extended duration in that zone; and (2) With respect to other materials and parts, means the capacity to withstand the heat associated with fire at least as well as steel in dimensions appropriate for the purpose for which they are used. "Fire resistant" - (1) With respect to heat or structural members means the capacity to withstand the heat associated with fire at least as well as aluminum alloy in dimensions appropriate for the purpose for which they are being used; and (2) With respect to fluid-carrying lines, fluid system parts, wiring, air ducts, fittings, and powerplant controls, means the capacity to perform the intended functions under the heat and other conditions likely to occur when there is fire at the place concerned. "Flame resistant" means not susceptible to combustion to the point of propagating a flame, beyond safe limits, after the ignition source is removed. "Flammable" with respect to a fluid or gas, means susceptible to igniting readily or to exploding. "Flap extended speed" means the highest speed permissible with wing flaps in a prescribed extended position. "Flash resistant" means not susceptible to burning violently when ignited. "Flight crewmember" means a pilot, flight engineer, or flight navigator assigned to duty in an aircraft during flight time. "Flight level" means a level of constant atmospheric pressure related to a reference datum of 29.92 inches of mercury. Each is stated in three digits that represent hundreds of feet. For example, flight level 250 represents a barometric altimeter indication of 25,000 feet; flight level 255, an indication of 25,500 feet. "Flight plan" means specified information, relating to the intended flight of an aircraft, that is filed orally or in writing with air traffic control. "Flight time" means the time from the moment the aircraft first moves under its own power for the purpose of flight until the moment it comes to rest at the next point of landing. ("Block-to-block" time.) "Flight visibility" means the average forward horizontal distance, from the cockpit of an aircraft in flight, at which prominent unlighted objects may be seen and identified by day and prominent lighted objects may be seen and identified by night. "Foreign air carrier" means any person other than a citizen of the United States who undertakes directly, by lease or other arrangement, to engage in air transportation. "Foreign air commerce" means the carriage by aircraft of persons or property for compensation or hire, or the carriage of mail by aircraft, or the operation or navigation of the aircraft in the conduct or furtherance of a business or vocation, in commerce between a place in the United States and any place outside of the United States, whether that commerce moves wholly by aircraft or partly by aircraft and partly by other forms of transportation. "Glider" means a heavier-than-air aircraft, that is supported in flight by the dynamic reaction of the air against its lifting surfaces and whose free flight does not depend principally on an engine. "Ground visibility" means prevailing horizontal visibility near the earth's surface as reported by the United States National Weather Service or an accredited observer. "Gyrodyne" means a rotorcraft whose rotors are normally engine-driven for takeoff, hovering, and landing, and for forward flight through part of its speed range, and whose means of propulsion, consisting usually of conventional propellers, is independent of the rotor system. "Gyroplane" means a rotorcraft whose rotors are not engine- driven except for initial starting, but are made to rotate by action of the air when the rotorcraft is moving; and whose means of propulsion, consisting usually of conventional propellers, is independent of the rotor system. "Helicopter" means a rotorcraft that, for its horizontal motion, depends principally on its engine-driven rotors. "heliport" means an area of land, water, or structure used or intended to be used for the landing and takeoff of helicopters. "Idle thrust" means the jet thrust obtained with the engine power control lever set at the stop for the least thrust position at which it can be placed. "IFR conditions" means weather conditions below the minimum for flight under visual flight rules. "IFR over-the-top," with respect to the operation of aircraft, means the operation of an aircraft over-the-top on an IFR flight plan when cleared by air traffic control to maintain "VFR conditions" or "VFR conditions on top." "Indicated airspeed" means the speed of an aircraft as shown on its pitot static airspeed indicator calibrated to reflect standard atmospheric adiabatic compressible flow at sea level uncorrected for airspeed system errors. "Instrument" means a device using an internal mechanism to show visually or aurally the attitude, altitude, or operation of an aircraft or aircraft part. It includes electronic devices for automatically controlling an aircraft in flight. "Interstate air commerce" means the carriage by aircraft of persons or property for compensation or hire, or the carriage of mail by aircraft, or the operation or navigation of aircraft in the conduct or furtherance of a business or vocation, in commerce between a place in any State of the United States, or the District of Columbia, and a place in any other State of the United States, or the District of Columbia; or between places in the same State of the United States through the airspace over any place outside thereof; or between places in the same territory or possession of the United States, or the District of Columbia. "Intrastate air transportation" means the carriage of persons or property as a common carrier for compensation or hire, by turbojet-powered aircraft capable of carrying thirty or more persons, wholly within the same State of the United States. "Interstate air transportation" means the carriage by aircraft of persons or property as a common carrier for compensation or hire, or the carriage of mail by aircraft, in commerce, (1) Between a place in a State of the District of Columbia and another place in another State or the District of Columbia; (2) Between places in the same State through the airspace of any place outside that State; or (3) Between places in the same possession of the United States; whether that commerce moves wholly by aircraft or partly by aircraft and partly by other forms of transportation. "Kite" means a framework, covered with paper, cloth, metal, or other material, intended to be flown at the end of a rope or cable, and having as its only support the force of the wind moving past its surfaces. "Landing gear extended speed" means the maximum speed at which an aircraft can be safely flown with the landing gear extended. "Landing gear operating speed" means the maximum speed at which the landing gear can be safely extended or retracted. "Large aircraft" means aircraft of more than 12,500 pounds, maximum certificated takeoff weight. "Lighter-than-air aircraft" means aircraft that can rise and remain suspended by using contained gas weighing less than the air that is displaced by the gas. "Load factor" means the ratio of a specified load to the total weight of the aircraft. The specified load is expressed in terms of any of the following: aerodynamic forces, inertia forces, or ground or water reactions. "Mach number" means the ratio of true airspeed to the speed of sound. "Main rotor" means the rotor that supplies the principal lift to a rotorcraft. "Maintenance" means inspection, overhaul, repair, preservation, and the replacement of parts, but excludes preventative maintenance. "Major alteration" means an alteration not listed in the aircraft, aircraft engine, or propeller specifications - (1) That might appreciably affect weight, balance, structural strength, performance, powerplant operation, flight characteristics, or other qualities affecting airworthiness; or (2) That is not done according to accepted practices or cannot be done by elementary operations. "Major repair" means a repair - (1) That, if improperly done, might appreciably affect weight, balance, structural strength, performance, powerplant operation, flight characteristics, or other qualities affecting airworthiness; or (2) That is not done according to accepted practices or cannot be done by elementary operations. "Manifold pressure" means absolute pressure as measured at the appropriate point in the induction system and usually expressed in inches of mercury. "Medical certificate" means acceptable evidence of physical fitness on a form prescribed by the Administrator. "Minimum descent altitude" means the lowest altitude, expressed in feet above mean sea level, to which descent is authorized on final approach or during circle-to-land maneuvering in execution of a standard instrument approach procedure, where no electronic glide slope is provided. "Minor alteration" means an alteration other than a major alteration. "Minor repair" means a repair other than a major repair. "Navigable airspace" means airspace at and above the minimum flight altitudes prescribed by our under this chapter, including airspace needed for safe takeoff and landing. "Night" means the time between the end of evening civil twilight and the beginning of morning civil twilight, as published in the American Air Almanac, converted to local time. "Nonprecision approach procedure" means a standard instrument approach procedure in which no electronic glide slope is provided. "Operate," with respect to aircraft, means use, cause to use or authorize to use aircraft, for the purpose (except as provided in section 91.10 of this chapter) or air navigation including the piloting of aircraft, with or without the right of legal control (as owner, lessee, or otherwise). "Operational control," with respect to a flight, means the exercise of authority over initiating, conducting, or terminating a flight. "Overseas air commerce" means the carriage by aircraft of persons or property for hire, or the carriage of mail by aircraft, or the operation or navigation of aircraft in the conduct of furtherance of a business or vocation, in commerce between a place in any State of the United States, or the District of Columbia, and any place in a territory or possession of the United States; or between a place in a territory or possession of the United States, and a place in any other territory or possession of the United States. "Overseas air transportation" means the carriage by aircraft of persons or property as a common carrier for compensation or hire, or the carriage of mail by aircraft, in commerce- (1) Between a place in a State or the District of Columbia and a place in a possession of the United States; or (2) Between a place in a possession of the United States an a place in another possession of the United States; whether that commerce moves wholly by aircraft or partly by aircraft and partly by other forms of transportation. "Over-the-top" means above the layer of clouds or other obscuring phenomena forming the ceiling. "Parachute" means a device used or intended to be used to retard the fall of a body or object through the air. "Person" means an individual, firm, partnership, corporation, company, association, joint-stock association, or governmental entity. It includes a trustee, receiver, assignee, or similar representative of any of them. "Pilotage" means navigation by visual reference to landmarks. "Pilot in command" means the pilot responsible for the operation and safety of an aircraft during flight time. "Pitch setting" means the propeller blade setting as determined by the blade angle measured in a manner, and at a radius, specified by the instruction manual for the propeller. "Positive control" means control of all air traffic, within designated airspace, by air traffic control. "Precision approach procedure" means a standard instrument approach procedure in which an electronic glide slope is provided, such as ILS and PAR. "Preventive maintenance" means simple or minor preservation operations and the replacement of small standard parts not involving complex assembly operations. "Prohibited area" means designated airspace within which the flight of aircraft is prohibited. "Propeller" means a device for propelling an aircraft that has blades on an engine-driven shaft and that, when rotated, produces by its action on the air, a thrust approximately perpenicular to its plane of rotation. It includes control components normally supplied by its manufacturer, but does not include main and auxiliary rotors or rotating airfoils of engines. "Public aircraft" means aircraft used only in the service of the government, or a political subdivision. It does not include any government-owned aircraft engaged in carrying persons or property for commercial purposes. "Rated continuous OEI power," with respect to rotorcraft turbine engines, means the approved brake horsepower developed under static conditions at specified altitudes and temperatures within the operating limitations established for the engine under Part 33 of this chapter, and limited in use to the time required to complete the flight after the failure of one engine of a multiengine rotorcraft. "Rated maximum continuous augmented thrust," with respect to turbojet engine type certification, means the approved jet thrust that is developed statically or in flight, in standard atmosphere at a specified altitude, with fluid injection or with the burning of fuel in a separate combustion chamber, within the engine operating limitations established under Part 33, and approved for unrestricted periods of use. "Rated maximum continuous thrust," with respect to turbojet engine type certification, means the approved jet thrust that is developed statically or in flight, in standard atmosphere at a specified altitude, without fluid injection and without the burning of fuel in a separate combustion chamber, within the engine operating limitations established under Part 33 of this chapter, and approved for unrestricted periods of use. "Rated takeoff augmented thrust," with respect to turbojet engine type certification, means the approved jet thrust that is developed statically under sea level conditions, with fluid injection or with the burning of fuel in a separate combustion chamber, within the engine operating limitations established under Part 33, and limited in use to periods of not over 5 minutes for takeoff operation. "Rated takeoff power," with respect to reciprocating, turbopropeller, and turboshaft engine type certification, means the approved brake horsepower that is developed statically under standard sea level conditions, within the engine operating limitations established under Part 33, and limited in use to periods of not over 5 minutes for takeoff operation. "Rated 30-minute power," with respect to helicopter turbine engines, means the maximum brake horsepower, developed under static conditions at specified altitudes and atmospheric temperatures, under the maximum conditions of rotor shaft rotational speed and gas temperature, and limited in use to periods of not over 30 minutes as shown on the engine data sheet. "Rated 2 1/2-minute power," with respect to helicopter turbine engines, means the brake horsepower, developed statically in standard atmosphere at sea level, or at a specified altitude, for one-engine-out operation of multi- engine helicopters for 2 1/2-minutes at rotor shaft rotation speed and gas temperature established for this rating. "Rating" means a statement that, as part of a certificate, set forth special conditions, privileges, or limitations. "Reporting point" means a geographical location in relation to which the position of an aircraft is reported. "Restricted area" means airspace designated under Part 73 of this chapter within which the flight of aircraft, while not wholly prohibited, is subject to restriction. "RNAV waypoint (W/P)" means a predetermined geographical position used for route or instrument approach definition or progress reporting purposes that is defined relative to a VORTAC station position. "Rocket" means an aircraft propelled by ejected expanding gases generated in the engine from self-contained propellants and not dependent on the intake of outside substances. It includes any part which becomes separated during the operation. "Rotorcraft" means a heavier-than-air aircraft that depends principally for its support in flight on the lift generated by one or more rotors. "Rotorcraft-load combination" means the combination of a rotorcraft and an external load, including the external load attaching means. Rotorcraft-load combinations are designated as Class A, Class B, Class C, and Class D, as follows: (1) "Class A rotorcraft-load combination" means one in which the external load cannot move freely, cannot be jettisoned, and does not extend below the landing gear. (2) "Class B rotorcraft-load combination" means one in which the external load is jettisonable and is lifted free of land or water during the rotorcraft operations. (3) "Class C rotorcraft-load combination" means one in which the external load is jettisonable and remains in contact with land or water during the rotorcraft operation. (4) "Class D rotorcraft-load combination" means one in which the external load is other than Class A, B, or C and has been specifically approved by the Administrator for that operation. "Route segment" means a part of a route. Each end of that part is identified by- (1) a continental or insular geographical location; or (2) a point at which a definite radio fix can be established. "Sea level engine" means a reciprocating aircraft engine having a rated takeoff power that is producible only at sea level. "Second in command" means a pilot who is designated to be second in command of an aircraft during flight time. "Show," unless the context otherwise requires, means to show to the satisfaction of the Administrator. "Small aircraft" means aircraft of 12,500 pounds or less, maximum certificated takeoff weight. "Standard atmosphere" means the atmosphere defined in the U.S. Standard Atmosphere, 1962 (Geopotential altitude tables). "Stopway" means an area beyond the takeoff runway, no less wide that the runway and centered upon the extended centerline of the runway, able to support the airplane during an aborted takeoff, without causing structural damage to the airplane, and designated by the airport authorities for use in decelerating the airplane during an aborted takeoff. "Takeoff power"- (1) With respect to reciprocating engines, means the brake horsepower that is developed under standard sea level conditions, and under the maximum conditions of crankshaft rotational speed and engine manifold pressure approved for the normal takeoff, and limited in continuous use to the period of time shown in the approved engine specification; and (2) With respect to turbine engines, means the brake horsepower that is developed under static conditions at a specified altitude and atmospheric temperature, and under the maximum conditions of rotorshaft rotational speed and gas temperature approved for the normal takeoff, and limited in continuous use to the period of time shown in the approved engine specification. "Takeoff safety speed" means a referenced airspeed obtained after lift-off at which the required one-engine-inoperative climb performance can be achieved. "Takeoff thrust" with respect to turbine engines, means the jet thrust that is developed under static conditions at a specific altitude and atmospheric temperature under the maximum conditions of rotorshaft rotational speed and gas temperature approved for the normal takeoff, and limited in continuous use to the period of time shown in the approved engine specification. "Time in service," with respect to maintenance time records, means the time from the moment an aircraft leaves the surface of the earth until it touches it at the next point of landing. "True airspeed" means the airspeed of an aircraft relative to undisturbed air. True airspeed is equal to the equivalent airspeed multiplied by (po/p)^1/2. "Traffic pattern" means the traffic flow that is prescribed for aircraft landing at, taxiing on, or taking off from an airport. "Type"- (1) As used with respect to the certification, ratings, privileges, and limitations of airmen, means a specific make and basic model of aircraft, including modifications thereto that do not change its handling or flight characteristics. Examples include: DC-7, 1049, and F-27; and (2) As sued with respect to the certification of aircraft, means those aircraft which are similar in design. Examples include: DC-7 and DC-7C; 1049G and 1049H; and F-27 and F-27F. (3) As used with respect to the certification of aircraft engines, means those engines which are similar in design. For example, JT8D and JT8D-7 are engines of the same type, and JT9D-3A and JT9D-7 are engines of the same type. "United States," in a geographical sense, means (1) the States, the District of Columbia, Puerto Rico, and the possessions, including the territorial waters, and (2) the airspace of those areas. "United States air carrier" means a citizen of the United States who undertakes directly by lease, or other arrangement, to engage in air transportation. "VFR over-the-top," with respect to the operation of aircraft, means the operation of an aircraft over-the-top under VFR when it is not being operated on an IFR flight plan. 1.2 ABBREVIATIONS AND SYMBOLS In Subchapters A through K of this chapter: AGL means above ground level. ALS means approach lighting system. ASR means airport surveillance radar. ATC means air traffic control. CAS means calibrated airspeed. CAT II means Category II. CONSOL or CONSOLAN means a kind of low or medium frequency long range navigational aid. DH means decision height. DME means distance measuring equipment. EAS means equivalent airspeed. FAA means Federal Aviation Administration. FM means fan marker. GS means glide slope. HIRL means high-intensity runway lights. IAS means indicated airspeed. ICAO means International Civil Aviation Organization. IFR means instrument flight rules. ILS means instrument landing system. IM means ILS inner marker. INT means intersection. LDA means localizer-type directional aid. LFR means low-frequency radio range. LMM means compass locator at middle marker. LOC means ILS localizer. LOM means compass locator at outer marker. M means Mach number. MAA means maximum authorized IFR altitude. MALS means medium intensity approach light system. MALSR means medium intensity approach light system with runway alignment indicator lights. MCA means minimum crossing altitude. MDA means minimum descent altitude. MEA means minimum enroute IFR altitude. MM means ILS middle marker. MOCA means minimum obstruction clearance altitude. MRA means minimum reception altitude. MSL means mean sea level. NDB(ADF) means nondirectional beacon (automatic direction finder). NOPT means no procedure turn required. OEI means one engine inoperative. OM means ILS outer marker. PAR means precision approach radar. RAIL means runway alignment indicator light system. RBN means radio beacon. RCLM means runway centerline marking. RCLS means runway centerline light system. REIL means runway end identification lights. RR means low or medium frequency radio range station. RVR means runway visual range as measured in the touchdown zone area. SALS means short approach light system. SSALS means simplified short approach light system. SSALSR means simplified short approach light system with runway alignment indicator lights. TACAN means ultra-high frequency tactical air navigational aid. TAS means true airspeed. TCAS means a traffic alert and collision avoidance system. TDZL means touchdown zone lights. TVOR means very high frequency terminal omnigange station. Va means design maneuvering speed. Vb means design speed for maximum gust intensity. Vc means design cruising speed. Vd means design diving speed. Vdf/Mdf means demonstrated flight diving speed. Vf means design flap speed. Vfc/Mfc means maximum speed for stability characteristics. Vfe means maximum flap extended speed. Vh means maximum speed in level flight with maximum continuous power. Vle means maximum landing gear extended speed. Vlo means maximum landing gear operating speed. Vlof means lift-off speed. Vmc means minimum control speed with the critical engine inoperative. Vmo/Mmo means maximum operating limit speed. Vmu means minimum unstick speed. Vne means never exceed speed. Vno means maximum structural cruising speed. Vr means rotation speed. Vs means the stalling speed or the minimum steady flight speed at which the airplane is controllable. Vso means the stalling speed or the minimum steady flight speed in the landing configuration. Vs1 means the stalling speed or the minimum steady flight speed obtained in a specified configuration. Vtoss means takeoff safety speed for Category A rotorcraft. Vx means speed for best angle of climb. Vy means speed for best rate of climb. V1 means takeoff decision speed (formerly denoted as critical engine failure speed). V2 means takeoff safety speed. V2min means minimum takeoff safety speed. VFR means visual flight rules. VHF means very high frequency VOR means very high frequency omnirange station. VORTAC means collocated VOR and TACAN. 1.3 RULES OF CONSTRUCTION (a) In Subchapter A through K of this chapter, unless the context requires otherwise: (1) Words importing the singular include the plural; (2) Words importing the plural include the singular; and (3) Words importing the masculine gender include the feminine. (b) In Subchapters A through K of this chapter, the word: (1) "Shall" is used in an imperative sense; (2) "May" is used in a permissive sense to state authority or permission to do the act prescribed, and the words "no person may..." or "a person may not..." mean that no person is required, authorized, or permitted to do the act prescribed; and (3) "includes" means "includes but is not limited to."