§3.1 Definitions.

As used in this part terms are defined as follows: (a) Administration — (1) Administrator. The Administrator is the Administrator of Civil Aeronautics. (2) Applicant . An applicant is a person or persons applying for approval of an airplane or any part thereof. (3) Approved. Approved, when used alone or as modifying terms such as means, devices, specifications, etc., shall mean approved by the Administrator.[(See Sec. 3.18.) ] (b) General design — (1) Standard atmosphere . The standard atmosphere is an atmosphere defined as follows: (i) The air is a dry, perfect gas, (ii) The temperature at sea level is 59°F., (iii) The pressure at sea level is 29.92 inches Hg, .4 temperature is a temperature _of the airplane is airplane is ar ural loading conditions. (See § 3.181.) ural loading conditions. (See § 3.181.) (iv) The temperature gradient from sea level to the altitude at which the temperature equals -67°F. is - 0.003566°F./ft. and zero there above. (v) The density po at sea level under the above conditions is 0.002378 lb. sec. 2 /ft. 4 (2) Maximum anticipated air temperature . The maximum anticipated air temperature is a temperature specified for the purpose of compliance with the powerplant cooling standards. (See § 3.583.) (3) Airplane configuration. Airplane configuration is a term referring to the position of the various elements affecting the aerodynamic characteristics of the airplane (e.g. wing flaps, landing gear). (4) Aerodynamic coefficients . Aerodynamic coefficients are nondimensional coefficients for forces and moments. They correspond with those adopted by the U.S. National Advisory Committee for Aeronautics. (5) Critical engine(s) . The critical engine(s) is that engine(s) the failure of which gives the most adverse effect on the airplane flight characteristics relative to the case under consideration. (c) Weights — (1) Maximum weight . The maximum weight of the airplane is that maximum at which compliance with the requirements of this part of the Civil Air Regulations is demonstrated. (See § 3.74.) (2) Minimum weight. The minimum weight of the airplane is that minimum at which compliance with the requirements of this part of the Civil Air Regulations is demonstrated. (See § 3.75.) (3) Empty weight . The empty weight of the airplane is a readily reproducible weight which is used in the determination of the operating weights. (See § 3.73.) (4) Design maximum weight. The design maximum weight is the maximum weight of the airplane at which compliance is shown with the structural loading conditions. (See § 3.181.) (5) Design minimum weight. The design minimum weight is the minimum weight of the airplane at which compliance is shown with the structural loading conditions. (See § 3.181.) (6) Design landing weight. The design landing weight is the maximum airplane weight used in structural design for landing conditions at the maximum velocity of descent. (See § 3.242.) (7) Design unit weight. The design unit weight is a representative weight used to show compliance with the structural design requirements: (i) Gasoline 6 pounds per U.S. gallon. (ii) Lubricating oil 7.5 pounds per U.S. gallon. (iii) Crew and passengers 170 pounds per person. al IT-Sp ly f (d) Speeds — (1) IAS . Indicated air speed is equal to the pitot static airspeed indicator reading as installed in the airplane without correction for airspeed indicator system errors but including the sea level standard adiabatic compressible flow correction. (This latter correction is included in the calibration of the air-speed instrument dials.) (2) CAS . Calibrated air speed is equal to the air-speed indicator reading corrected for position and instrument error. (As a result of the sea level adiabatic compressible flow correction to the air-speed instrument dial, CAS is equal to the true air speed TAS in standard atmosphere at sea level.) (3) EAS . Equivalent air speed is equal to the air-speed indicator reading corrected for position error, instruments error, and for adiabatic compressible flow for the particular altitude. (EAS is equal to CAS at sea level in standard atmosphere.) (4) TAS . True air speed of the airplane relative to undisturbed air. (TAS=EAS( r 0/r ) « ). (5) Vc. The design cruising speed. (See § 3.184.) (6) Vd . The design diving speed. (See § 3.184.) (7) Vf . The design flap speed for flight loading conditions with wing flaps in the landing position. (See § 3.190.) (8) Vfe. The flap extended speed is a maximum speed with wing flaps in a prescribed extended position. (See § 3.742.) (9) Vh . The maximum speed obtainable in level flight with rated rpm and power. (10) Vmc . The minimum control speed with the critical engine inoperative. (See § 3.111.) (11) Vne . The never-exceed speed. (See § 3.739.) (12) Vno . The maximum structural cruising speed. (See § 3.740.) (13) Vp . The design maneuvering speed. (See § 3.184.) (14) Vsf . The stalling speed computed at the design landing weight with the flaps fully extended. (See § 3.190.) (15) Vs0. The stalling speed or the minimum steady flight speed with wing flaps in the landing position. (See § 3.82.) (16) Vs1 . The stalling speed or the minimum steady flight speed obtained in a specified configuration. (See § 3.82.) (17) Vx. The speed for best angle of climb. (18) Vy = The speed for best rate of climb. (e) Structural — (1) Limit load . A limit load is the maximum load anticipated in normal conditions of operation. (See § 3.171.) (2) Ultimate load . An ultimate load is a limit load multiplied by the appropriate factor of safety. (See § 3.173.) (3) Factor of safety . The factor of safety is a design factor used to provide for the possibility of loads greater than those anticipated in normal conditions of operation and for uncertainties in design. (See § 3.172.) (4) Load factor . The load factor is the ratio of a specified load to the total weight of the airplane; the specified load may be expressed in terms of any of the following: aerodynamic forces, inertia forces, or ground or water reactions. (5) Limit load factor. The limit load factor is the load factor corresponding with limit loads. (6) Ultimate load factor. The ultimate load factor is the load factor corresponding with ultimate loads. (7) Design wing area. The design wing area is the area enclosed by the wing outline (including wing flaps in the retracted position and ailerons, but excluding fillets or fairings) on a surface containing the wing chords. The outline is assumed to be extended through the nacelles and fuselage to the plane of symmetry in any reasonable manner. (8) Balancing tail load. A balancing tail load is that load necessary to place the airplane in equilibrium with zero pitch acceleration. (9) Fitting . A fitting is a part or terminal used to join one structural member to another. (See § 3.306.) (f) Power installation1 — (1) Brake horsepower . Brake horsepower is the power delivered at the propeller shaft of the engine. 1 For engine airworthiness requirements see Part 13 of the Civil Air Regulations. For propeller airworthiness requirements see Part 14 of the Civil Air Regulations. (2) Take-off power . Take-off power is the brake horsepower developed under standard sea level conditions, under the maximum conditions of crankshaft rotational speed and engine manifold pressure approved for use in the normal take-off, and limited in use to a maximum continuous period as indicated in the approved engine specifications. ippropriate point in the (3) Maximum continuous power . Maximum continuous power is the brake horsepower developed in standard atmosphere at a specified altitude under the maximum conditions of crankshaft rotational speed and engine manifold pressure approved for use during periods of unrestricted duration. (4) Manifold pressure. Manifold pressure is the absolute pressure measured at the appropriate point in the induction system, usually in inches of mercury. (5) Critical altitude . The critical altitude is 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: (i) 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. (ii) The maximum continuous rated manifold pressure, in the case of engines the maximum continuous power of which is governed by a constant manifold pressure. (6) Pitch setting . Pitch setting is the propeller blade setting determined by the blade angle measured in a manner, and at a radius, specified in the instruction manual for the propeller. (7) Feathered pitch . Feathered pitch is the pitch setting, which in flight, with the engines stopped, gives approximately the minimum drag and corresponds with a windmilling torque of approximately zero. (8) Reverse pitch . Reverse pitch is the propeller pitch setting for any blade angle used beyond zero pitch (e.g., the negative angle used for reverse thrust). (g) Fire protection — (1) Fireproof . Fireproof material means material which will withstand heat at least as well as steel in dimensions appropriate for the purpose for which it is to be used. When applied to material and parts used to confine fires in designated fire zones, fireproof means that the material or part will perform this function under the most severe conditions of fire and duration likely to occur in such zones. (2) Fire-resistant . When applied to sheet or structural members, fire-resistant material means a material which will withstand heat at least as well as aluminum alloy in dimensions appropriate for the purpose for which it is to be used. When applied to fluid-carrying lines, other flammable fluid system components, wiring, air ducts, fittings, and powerplant controls, this term refers to a line and fitting assembly, component, wiring, or duct, or controls which will perform the intended functions under the heat and other conditions likely to occur at the particular location. (3) Flame-resistant. Flame-resistant material means material which will not support combustion to the point of propagating, beyond safe limits, a flame after the removal of the ignition source. violently when es which will ignite readily or explode. lations . Fcate. tion to the applicable requir onditions or limitations prescribed by the Civil Air uired. (4) Flash-resistant. Flash-resistant material means material which will not burn violently when ignited. (5) Flammable . Flammable pertains to those fluids or gases which will ignite readily or explode. CERTIFICATION