(b) Rotorcraft types—(1) Rotorcraft. A rotorcraft is any aircraft deriving its principal lift from one or more rotors.

(2) Helicopter. A helicopter is a rotorcraft which depends principally for its support and motion in the air upon the lift generated by one or more powerdriven rotors, rotating on substantially vertical axes.

(3) Gyroplane. A gyroplane is a rotorcraft which depends principally for its support upon the lift generated by one or more rotors which are not power driven, except for initial starting, and which are caused to rotate by the action of the air when the rotorcraft is in motion. The propulsion is independent of the rotor system and usually consists of conventional propellers.

(4) Gyrodyne. A gyrodyne is a rotorcraft which depends principally for its support upon the lift generated by one or more rotors, which are partially power driven, rotating on substantially vertical axes. The propulsion is independent of the rotor system and usually consists of conventional propellers.

(c) General design—(1) Standard atmosphere. The standard atmosphere is an atmosphere (see NACA Technical Report 1235) 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,

(iv) The temperature gradient from sea level to the altitude at which the temperature equals -69.7° F. is -0.003566° F./ft. and zero thereabove, and

(v) The density po at sea level under the above conditions is 0.002377 pound sec2/ft'.

(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 § 7.451.)

(3) Aerodynamic coefficients. Aerodynamic coefficients are nondimensional coefficients for forces and moments. They correspond with those adopted by the National Aeronautics and Space Administration (formerly the National Advisory Committee for Aeronautics).

(4) Autorotation. Autorotation is a rotorcraft flight condition in which the lifting rotor is driven entirely by the action of the air when the rotorcraft is in motion.

(5) Autorotative landing. An autorotative landing is any ianding of a rotorcraft in which the entire maneuver is accomplished without the application of power to the rotor.

(6) [Reserved]

Ground res

(7) Ground resonance. onance is the mechanical instability encountered when the rotorcraft is in contact with the ground.

(8) Mechanical instability. Mechanical instability is an unstable resonant condition due to the interaction between the rotor blades and the rotorcraft structure, while the rotorcraft is on the ground or airborne.

(d) Weights—(1) Maximum weight. The maximum weight of the rotorcraft is that maximum at which compliance with the requirements of this part is demonstrated. (See § 7.101.)

(2) Minimum weight. The minimum weight of the rotorcraft is that minimum at which compliance with the requirements of this part is demonstrated. (See § 7.101.)

(3) Empty weight. The empty weight of the rotorcraft is a readily reproducible weight which is used in the determination of the operating weights. (See § 7.104.)

(4) Design maximum weight. The design maximum weight is the maximum weight of the rotorcraft at which compliance is shown with the structural loading conditions. (See § 7.101.)

(5) Design minimum weight. The design minimum weight is the minimum weight of the rotorcraft at which compliance is shown with the structural loading conditions. (See § 7.101.)

(6) 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. For other fuels, a design unit weight or range of weights appropriate to the type of fuels shall be established.

(ii) Lubricating oil 7.5 pounds per U. S. gallon.

(iii) Crew and passengers 170 pounds per person.

(e) Speeds-(1) IAS. Indicated air speed is equal to the pitot static air-speed indicator reading as installed in the rotorcraft without correction for air-speed indicator system errors but including the sea level standard adiabatic compressible flow correction. (This latter correction is included in the calibration of the airspeed instrument dials.) (See 87.612 and 7.732.)

(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 airspeed 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, instrument 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 rotorcraft relative to undisturbed air. (TAS-EAS(po/p) 1/2)

(5) VH. The maximum speed obtainable in level flight with rated rpm and power.

(6) VNE. The never-exceed speed. (See § 7.711.)

(7) Vx. The speed for best angle of climb.

(8) Vr. The speed for best rate of climb.

(f) Structural-(1) Limit load. A limit load is the maximum load anticipated in normal conditions of operation. (See §7.200.)

(2) Ultimate load. An ultimate load is a limit load multiplied by the appropriate factor of safety. (See § 7.200.) (3) Factor of safety. The factor of safety is a design factor used to provide

The ulti

(6) Ultimate load factor. mate load factor is the load factor corresponding with ultimate loads.

(7) Fitting. A fitting is a part or terminal used to join one structural member to another. (See § 7.307 (d).)

(g) Powerplant installation 1—(1) Brake horsepower. Brake horsepower is the power delivered at the propeller shaft of the engine.

(2) Take-off power or thrust. (1) Take-off power for reciprocating engines is the brake horsepower developed under standard sea level conditions, under the maximum conditions of crankshaft rotational speed and engine manifold pressure approved for the normal take-off, and limited in use to a maximum continuous period as indicated in the approved engine specification.

(ii) Take-off power for turbine engines is the brake horsepower developed under static conditions at specified altitudes and atmospheric temperatures, under the maximum conditions of engine rotor shaft rotational speed and gas temperature approved for normal take-off, and limited in use to a maximum continuous period as indicated in the approved engine specification.

(iii) Take-off thrust for turbine engines is the jet thrust developed under static conditions at specified altitudes and atmospheric temperatures, under the maximum conditions of engine rotor shaft rotational speed and gas temperature approved for the normal take-off, and limited in use to a maximum continuous period as indicated in the approved engine specification.

(3) Maximum continuous power or thrust. (i) Maximum continuous power for reciprocating engines is the brake

1 For engine airworthiness requirements see Part 13 of this subchapter.

Instrument markings; general.

7.732 Air-speed indicator.

7.733

Magnetic direction indicator.

7.734 Powerplant instruments; general. 7.735 Oil quantity indicator.

7.736 Fuel quantity indicator.

Control markings.

Miscellaneous markings and placards.

ROTORCRAFT FLIGHT MANUAL

General.

Operating limitations.

7.742 Operating procedures.

7.743

Performance information.

7.744 Marking and placard information.

ROTORCRAFT IDENTIFICATION DATA

7.750
7.751 Identification marks.

Identification plate.

AUTHORITY: §§ 7.0 to 7.751 issued under sec. 205, 52 Stat. 984, as amended; 49 U. S. C. 425. Interpret or apply secs. 601, 603, 52 Stat. 1007, as amended, 1009, as amended; 49 U.S. C. 551, 553.

AUTHORITY NOTE: Additional citation of authority to Part 7 was appended by Amendment 7-4, 24 F.R. 7076, Sept. 1, 1959, as follows: "(Secs. 313(a), 601, 603, 72 Stat. 752, 775, 776; 49 U.S.C. 1354(a), 1421, 1423)"

SOURCE: §§ 7.0 to 7.751 appear at 21 F. R. 3744, June 2, 1956, except as otherwise noted.

CROSS REFERENCES: For Special Civil Air Regulation with respect to facilitation of experiments with exterior lighting systems, see SR-392B in Part 3 of this subchapter.

For Special Civil Air Regulation with respect to Class I and Class II provisional type and airworthiness certificates for the operation of aircraft, see SR-425C in Part 1 of this subchapter.

Subpart A-General

APPLICABILITY AND DEFINITIONS § 7.0 Applicability of this part.

This part establishes standards with which compliance shall be demonstrated for the issuance of and changes to type certificates for Transport Category A and Transport Category B rotorcraft. This part, until superseded or rescinded, shall apply to all transport category rotorcraft for which applications for type certification in the transport categories are made after the effective date of this part (August 1, 1956).

horsepower developed in standard atmosphere at a specified altitude, under the maximum conditions of crankshaft rotational speed and engine manifold pressure, and approved for use during periods of unrestricted duration.

(ii) Maximum continuous power for turbine engines is the brake horsepower developed at specified altitudes, atmospheric temperatures, and flight speeds, under the maximum conditions of engine rotor shaft rotational speed and gas temperature, and approved for use during periods of unrestricted duration.

(iii) Maximum continuous thrust for turbine engines is the jet thrust developed at specified altitudes, atmospheric temperatures, and flight speeds, under the maximum conditions of engine rotor shaft rotational speed and gas temperature, and approved for use during periods of unrestricted duration.

(4) Gas temperature. Gas temperature for turbine engines is the temperature of the gas stream obtained as indicated in the approved engine specification.

Manifold

(5) Manifold pressure. pressure is the absolute pressure measured at the appropriate point in the induction system, usually in inches of mercury.

(6) 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.

(h) Propellers and rotors —(1) Rotor. Rotor is a system of rotating airfoils.

(2) Main rotor. The main rotor is the main system of rotating airfoils providing sustentation for the rotorcraft.

For propeller airworthiness requirements see Part 14 of this subchapter.

(3) Auxiliary rotor. An auxiliary rotor is one which serves either to counteract the effect of the main rotor torque on the rotorcraft, or to maneuver the rotorcraft about one or more of its three principal axes.

(4) Axis of no feathering. The axis of no feathering is the axis about which there is no first harmonic feathering or cyclic pitch variation."

(5) Plane of rotor disc. The plane of rotor disc is a reference plane at right angles to the axis of no feathering.

(6) Tip speed ratio. The tip speed ratio is the ratio of the rotorplane flight velocity component in the plane of rotor disc to the rotational tip speed of the rotor blades expressed as follows:

(i) Fire protection—(1) Fireproof. Fireproof material means a 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 See NACA Technical Note No. 1604.