flames, or other noxious gases from entering into any compartment occupied by the crew or passengers. (2) Ventilation and drafts shall be controlled within each compartment so that any fire likely to occur in the compartment will not progress beyond safe limits. NOTE: For compartments having a volume not in excess of 500 cu. ft. an airflow of not more than 1,500 cu. ft. per hour is considered acceptable. For larger compartments lesser airflow may be applicable. (3) The compartment shall be completely lined with fire-resistant material. (4) Consideration shall be given to the effect of heat within the compartment on adjacent critical parts of the airplane. (e) Class E. On airplanes used for the carriage of cargo only it shall be acceptable to classify the cabin area as a Class "E" compartment. Compliance shall be shown with the following: (1) The compartment shall be completely lined with fire-resistant material. (2) The compartment shall be equipped with a separate system of an approved type smoke or fire detector to give warning at the pilot or flight engineer station. (3) Means shall be provided to shut off the ventilating airflow to or within the compartment. Controls for such means shall be accessible to the flight crew in the crew compartment. (4) Means shall be provided to exclude hazardous quantities of smoke, flames, or noxious gases from entering the flight crew compartment. (See § 4b.380 (c) for protective breathing equipment.) (5) Required crew emergency exits shall remain accessible under all cargo loading conditions. [15 F.R. 3543, June 8, 1950, as amended by Amdt. 4b-6, 17 F.R. 1094, Feb. 5, 1952; Amdt. 4b-8, 18 F.R. 2215, Apr. 18, 1953; Amdt. 4b-2, 20 F.R. 5306, July 26, 1955; Amdt. 4b-10, 24 F.R. 3153, Apr. 23, 1959] tion of the extinguishing agent in class C compartments shall be demonstrated by tests in flight. (b) It shall also be demonstrated during the tests prescribed in paragraph (a) of this section that no inadvertent operation of smoke or fire detectors in adjacent or other compartments within the airplane would occur as a result of fire contained in any one compartment, either during or after extinguishment, unless the extinguishing system floods such compartments simultaneously. [15 F. R. 3543, June 8, 1950, as amended by Amdt. 4b-6, 17 F. R. 1095, Feb. 5, 1952] § 4b.384-1 Cargo and baggage compartments equipped with carbon dioxide fire extinguishers (FAA policies which apply to § 4b.384). The policies outlined in § 4b.484-1 apply. [Supp. 24, 19 F. R. 4463, July 20, 1954] § 4b.385 Flammable fluid fire protec tion. In areas of the airplane where flammable fluids or vapors might be liberated by leakage or failure in fluid systems, design precautions shall be made to safeguard against the ignition of such fluids or vapors due to the operation of other equipment, or to control any fire resulting from such ignition. [Amdt. 4b-6, 17 F. R. 1095, Feb. 5, 1952] § 4b.386 Combustion heater fire protection. (a) Combustion heater fire zones. The following shall be considered as combustion heater fire zones and shall be protected against fire in accordance with applicable provisions of §§ 4b.480 through 4b.486 and § 4b.489. (1) Region surrounding the heater, if such region contains any flammable fluid system components other than the heater fuel system which might be damaged by heater malfunctioning or which, in case of leakage or failure, might permit flammable fluids or vapors to reach the heaters. (2) Region surrounding the heater, if the heater fuel system incorporates fittings the leakage of which would permit fuel or vapors to enter this region. (3) That portion of the ventilating air passage which surrounds the combustion chamber except that no fire extinguishment need be provided in cabin ventilating air passages. (b) Ventilating air ducts. (1) Ventilating air ducts which pass through fire zones shall be of fireproof construction. (2) Unless isolation is provided by the use of fireproof valves or other equivalently effective means, the ventilating air duct downstream of the heater shall be of fireproof construction for a sufficient distance to assure that any fire originating from within the heater can be contained within the duct. (3) Portions of ventilating ducts passing through regions in the airplane where flammable fluid systems are located shall be so constructed or isolated from such systems that failure or malfunctioning of the flammable fluid system components cannot introduce flammable fluids or vapors into the ventilating airstream. (c) Combustion air ducts. (1) Combustion air ducts shall be of fireproof construction for a distance sufficient to prevent damage from backfiring or reverse flame propagation. (2) Combustion air ducts shall not communicate with the ventilating airstream unless it is demonstrated that flames from backfires or reverse burning cannot enter the ventilating airstream under any conditions of ground or flight operation including conditions of reverse flow or malfunctioning of the heater or its associated components. (3) Combustion air ducts shall not restrict prompt relief of backfires which can cause heater failure due to pressures generated within the heater. Pro (d) Heater controls; general. vision shall be made to prevent hazardous accumulations of water or ice on or within any heater control components, control system tubing, or safety controls. (e) Heater safety controls. (1) In addition to the components provided for normal continuous control of air temperature, air flow, and fuel flow, means independent of such components shall be provided with respect to each heater to shut off automatically that heater's ignition and fuel supply at a point remote from the heater when the heat exchanger temperature or ventilating air temperature exceed safe limits or when either the combustion air flow or the ventilating air flow becomes inadequate for safe operation. The means provided for this purpose for any individual heater shall be independent of all components serving other heaters the heat output of which is essential to the safe operation of the airplane. (2) Warning means shall be provided to indicate to the crew when a heater, the heat output of which is essential to the safe operation of the airplane, has been shut off by the operation of the automatic means prescribed in subparagraph (1) of this paragraph. (f) Air intakes. Combustion and ventilating air intakes shall be so located that no flammable fluids or vapors can enter the heater system under any conditions of ground or flight operation either during normal operation or as a result of malfunctioning, failure, or improper operation of other airplane components. (g) Heater exhaust. Heater exhaust systems shall comply with the provisions of § 4b.467 (a) and (b). In addition, provisions shall be made in the design of the heater exhaust system so that the products of combustion will be safely conveyed overboard to prevent the occurrence of the following: (1) Fuel leakage from the exhaust to surrounding compartments; (2) Exhaust gas impingement on surrounding equipment or structure: (3) Ignition of flammable fluids by the exhaust, when the exhaust is located in a compartment containing flammable fluid lines; (4) Restriction by the exhaust of the prompt relief of backfires which can cause heater failure due to pressure generated within the heater. (h) Heater fuel systems. Heater fuel systems shall comply with all portions of the powerplant fuel system requirements which affect safe heater operations. In addition, heater fuel system components within the ventilating airstream shall be protected by shrouds so that leakage from such components cannot enter the ventilating airstream. (i) Drains. Means shall be provided for safe drainage of fuel accumulations which might occur within the combustion chamber or the heat exchanger. Portions of such drains which operate at high temperatures shall be protected in the same manner as heater exhausts (see paragraph (g) of this section). Drains shall be protected against hazardous ice accumulations in flight and during ground operation. [Amdt. 4b-6, 17 F. R. 1095, Feb. 5, 1952, as amended by Amdt. 4b-8, 18 F. R. 2215, Apr. The powerplant installation shall be considered to include all components of the airplane which are necessary for its propulsion. It shall also be considered to include all components which affect the control of the major propulsive units or which affect their safety of operation between normal inspections or overhaul periods. (See §§ 4b.604 and 4b.613 for instrument installation and marking.) (a) Scope. Reciprocating engine installations shall comply with the provisions of this subpart. Turbine engine installations shall comply with such of the provisions of this subpart as are found applicable to the specific type of installation. (b) Functioning. All components of the powerplant installation shall be constructed, arranged, and installed in a manner which will assure their continued safe operation between normal inspections or overhaul periods. (c) Accessibility. Accessibility shall be provided to permit such inspection and maintenance as is necessary to assure continued airworthiness. (d) Electrical bonding. Electrical interconnections shall be provided to prevent the existence of differences of potential between major components of the powerplant installation and other portions of the airplane. [15 F. R. 3543, June 8, 1950, as amended by Amdt. 4b-6, 17 F. R. 1095, Feb. 5, 1952] § 4b.400-1 Engine and propeller operation (FAA policies which apply to § 4b.400). The engines and propellers should be observed during the flight test program to determine satisfactory operation of these systems and their associated components. [Supp. 24, 19 F. R. 4463, July 20, 1954] § 4b.400-2 Powerplant installation components (FAA interpretations which apply to § 4b.400). The term "all components" includes engines and propellers and their parts, appurtenances, and accessories which are furnished by the engine or propeller manufacturer and all other components of the powerplant installation which are furnished by the airplane manufacturer. For example: Fuel pumps, lines, valves, and other components of the fuel system which are integral parts of the type certificated engine are also components of the airplane powerplant installation. [Supp. 40, 23 F. R. 9018, Nov. 20, 1958] § 4b.401 Engines. (a) Type certification. All engines shall be type certificated in accordance with the provisions of Part 13 of this subchapter. (b) Engine isolation. The powerplants shall be arranged and isolated each from the other to permit operation in at least one configuration in a manner such that the failure or malfunctioning of any engine, or of any system of the airplane the failure of which can affect an engine, will not prevent the continued safe operation of the remaining engine(s) or require immediate action by a crew member for continued safe operation. (c) Control of engine rotation. Means shall be provided for individually stopping and restarting the rotation of any engine in flight, except that for turbine engine installations means for stopping the rotation need be provided only if such rotation could jeopardize the safety of the airplane. All components provided for this purpose which are located on the engine side of the fire wall and which might be exposed to fire shall be of fire-resistant construction. If hydraulic propeller feathering systems are used for this purpose, the feathering lines on all airplanes manufactured after June 30, 1954, shall be fire-resistant under the operating conditions which may be expected to exist when feathering is being accomplished. (See also § 4b.449.) (d) Rotor blade protection. Turbine powerplant installations shall include a means of protection such that the occurrence of rotor blade failure in any engine will not affect the operation of remaining engines nor jeopardize the continued safe operation of the airplane, unless the engine type certificate specifies that the engine rotor cases have been substantiated as capable of containing the damage resulting from rotor blade failure. (e) Engine turbine rotor. Design precautions shall be taken to minimize the probability of jeopardizing the safety of the airplane in the event of engine turbine rotor failure, unless the engine type certificate specifies that the turbine rotors have been demonstrated to provide sufficient strength to withstand damage inducing factors such as those which might result from abnormal rotor speeds, temperature, or vibration and the design and functioning of the powerplant systems associated with engine control devices, systems, and instrumentation are such as to give reasonable assurance that those engine operating limitations which adversely affect turbine rotor structural integrity will not be exceeded in service. [15 F. R. 3543, June 8, 1950, as amended by Amdt. 4b-6, 17 F. R. 1095, Feb. 5, 1952; Amdt. 4b-8, 18 F. R. 2215, Apr. 18, 1958; Amdt. 4b-2, 20 F.R. 5306, July 26, 1955; Amdt. 4b-6, 22 F.R. 5565, July 16, 1957] § 4b.401-1 Approval of automatic propeller feathering system (FAA policies which apply to § 4b.401(c)). All parts of the feathering device which are integral with the propeller or attached to it in a manner that may affect propeller airworthiness should be considered from the standpoint of the applicable provisions of Part 14 of this subchapter. The determination of the continuing eligibility of the propeller under the existing type certificate, when the device is installed or attached, will be made on the following basis: (a) The automatic propeller feathering system should not adversely affect normal propeller operation and should function properly under all temperature, altitude, airspeed, vibration, acceleration, and other conditions to be expected in normal ground and flight operation. (b) The automatic device should be demonstrated to be free from malfunc tioning which may cause feathering under any conditions other than those under which it is intended to operate. For example, it should not cause feathering during: (1) Momentary loss of power, (2) Approaches with reduced throttle settings. (c) The automatic propeller feathering system should be capable of operating in its intended manner whenever the throttle control is in the normal position to provide take-off power. No special operations at the time of engine failure should be necessary on the part of the crew in order to make the automatic feathering system operative. (d) The automatic propeller feathering installation should be such that not more than one engine will be feathered automatically even if more than one engine fails simultaneously. (e) The automatic propeller feathering installation should be such that normal operation may be regained after the propeller has begun to feather automatically. (f) The automatic propeller feathering installation should incorporate a switch or equivalent means by which to make the system inoperative. (See also § 4b. 10-2.) [Supp. 23, 19 F. R. 1818, Apr. 2, 1954] § 4b.401-2 Propeller feathering system operational tests (FAA policies which apply to § 4b.401(c)). (a) Tests should be conducted to determine the time required for the propeller to change from windmilling (with the propeller controls set for take-off) to the feathered position at the take-off safety speed, V.. (b) (1) The propeller feathering system should be tested to demonstrate nonrotation up to 1.2 times the maximum level flight speed with one engine inoperative or the speed employed in emergency descents whichever is higher with: Critical engine-Inoperative. (2) A sufficient speed range should be covered to assure that the propeller feathering angle established on the basis of the high speed requirement does not permit rotation in reverse at the lower speeds. In addition, the propeller should not inadvertently unfeather during these tests. (c) In order to demonstrate that the feathering system operates satisfactorily, the propeller should be feathered and unfeathered at the maximum operating altitude established in accordance with § 4b.722. The following data should be recorded: Time to feather propeller at the one-engineinoperative cruising speed. Time to unfeather propeller to 1,000 r. p. m. at maximum operating altitude and oneengine-inoperative cruising speed. Altitude of propeller feathering tests. Ambient air temperature of propeller feathering tests. [Supp. 24, 19 F. R. 4463, July 20, 1954] § 4b.401-3 Continued rotation of turbine engines (FAA policies which apply to § 4b.401(c)). (a) If means are not provided to completely stop the rotation of turbine engines it should be shown that continued rotation, either windmilling or controlled, of a shutdown turbine engine will not cause: (1) Powerplant (including engine and accessories) structural damage which will adversely affect other engines or the aircraft structure, (2) Flammable fluid to be pumped into a fire or onto an ignition source, or (3) A vibration mode which will adversely affect the aerodynamic or structural integrity of the airplane. 1 (b) Feathered propellers, brakes, doors or other means used to control turbine engine rotation need not produce a complete stop of engine rotation unless the continued rotation will cause any of the conditions set forth in paragraph (a) of this section. (c) If engine induction air duct doors, or shaft, or other types of brakes' are provided to control turbine engine rotation, no single fault or failure of the system controlling engine rotation should cause the inadvertent travel of the doors toward the closed position, or the 1 It may be assumed that the conditions in paragraph (a) of this section will not occur at engine rotor speeds up to 400 r.p.m. 2 The provision of doors or brakes is a protective feature to assure that the conditions of paragraph (a) of this section will not occur. Such provision, therefore, should be of a high order of reliability, and the probability should be remote that doors or brakes will not function normally on demand. inadvertent energizing of braking means, unless compensating features are provided to assure that engine failure or a critical operating condition will not occur. [Supp. 32, 22 F. R. 5793, July 20, 1957] § 4b.401-4 Engine operation with automatic propeller control system installed (FAA policies which apply to § 4b.401 (b)). (a) When an automatic control system for simultaneous r.p.m. control of all propellers is installed, it should be shown that no single failure or malfunction in this system or in an engine controlling this system will: (1) Cause the tolerable engine overspeed for this condition' to be exceeded at any time, and (2) Cause a loss of thrust which will cause the airplane to descend below the established takeoff path (§ 4b.116) if such system is certificated for use during takeoff and climb. This should be shown for all weights and altitudes for which certification is desired. A period of five seconds should be allowed from the time the malfunction occurs to the initial motion of the cockpit control for corrective action taken by the crew. (b) Compliance with this policy may be shown by, (1) analysis, (2) flight demonstration, or (3) a combination of analysis and flight demonstration. [Supp. 33, 22 F. R. 6883, Aug. 27, 1957] |