478 etc.) from the ceiling should not be positioned in the main aisle. Alternate locations should be used, e.g., over seat, on the side wall etc. These features should also be appropriately padded or rounded to preclude injury when persons are moving about the cabin. (Amendment 25-0) 444 - 460. [RESERVED]
479 SECTION 25.817 MAXIMUM NUMBER OF SEATS ABREAST
461. Section 25.817 Did Not Exist Prior to Amendment 25-15.
462. AMENDMENT 25-15, Effective October 24, 1967.
a. Regulation.
On airplanes having only one passenger aisle, no more than three seats abreast may be placed on each side of the aisle in any one row.
b. Guidance. On a twin-aisle airplane, a six-place seat assembly could be installed between the two aisles. (Amendment 25-15) 463 - 480. [RESERVED]
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481 SECTION 25.819 LOWER DECK SERVICE COMPARTMENTS (INCLUDING GALLEYS)
481. Section 25.819 Did Not Exist Prior to Amendment 25-53.
482. AMENDMENT 25-53, Effective August 31, 1980.
a. Regulation.
For airplanes with a service compartment located below the main deck, which may be occupied during taxi or flight but not during takeoff or landing, the following apply:
(a) There must be at least two emergency evacuation routes, one at each end of lower deck service compartment, or two having sufficient separation within each compartment, which could be used by each occupant of the lower deck service compartment to rapidly evacuate to the main deck under normal and emergency lighting conditions. The routes must provide for the evacuation of incapacitated persons, with assistance. The use of the evacuation routes may not be dependent on any powered device. The routes must be designed to minimize the possibility of blockage which might result from fire, mechanical or structural failure, or persons standing on top of or against the escape routes. In the event the airplane's main power system or compartment main lighting system should fail, emergency illumination for each lower deck service compartment must be automatically provided.
(b) There must be a means for two-way voice communication between the flight deck and each lower deck service compartment.
(c) There must be an aural emergency alarm system, audible during normal and emergency conditions, to enable crewmembers on the flight deck and at each required floor level emergency exit to alert occupants of each lower deck service compartment of an emergency situation.
(d) There must be a means, readily detectable by occupants of each lower deck service compartment, that indicates when seat belts should be fastened.
(e) If a public address system is installed in the airplane, speakers must be provided in each lower deck service compartment.
(f) For each occupant permitted in a lower deck service compartment, there must be a forward or aft facing seat which meets the requirements of § 25.785(c) and must be able to withstand maximum flight loads when occupied.
(g) For each powered lift system installed between a lower deck service compartment and the main deck for the carriage of persons or equipment, or both, the system must meet the following requirements:
(l) Each lift control switch outside the lift, except emergency stop buttons, must be designed to prevent the activation of the lift if the lift door, or the hatch required by paragraph (g)(3) of this section, or both, are open.
(2) An emergency stop button, that when activated will immediately stop the lift, must be installed within the lift and at each entrance to the lift.
(3) There must be a hatch capable of being used for evacuating persons from the lift that is openable from inside and outside the lift without tools, with the lift in any position.
b. Guidance.
(1) The following should be used for any installation regardless of certification basis:
(Amendment 25-53)
(i) The installation of a lower deck service compartment normally results in cart restraint locations on both the main and lower decks. At these locations, the carts are normally restrained by a fitting in the floor, commonly called a mushroom. There are two typical types of mushrooms. One is usually retractable, located in an aisle or passageway, and capable of restraining the cart for inflight load conditions only. The other mushroom is usually fixed, located in a galley, lift or cabinet, and generally capable of restraining the cart during taxi, takeoff, and landing (TT&L). If necessary, control of the number of carts allowed on each deck should be provided. For the TT&L condition, there should be enough TT&L mushrooms for each cart on the airplane. In order to be assured the carts can be taken to such a mushroom, there should be at least two independently powered and controlled lifts between the main and lower decks. If there are not at least two such lifts, it should be demonstrated by actual test that all carts can be transported up or down between decks. It is acceptable to transport the contents and cart separately by average flight attendants. If two such lifts are not installed and transportablity is not demonstrated, at any given time, there should not be more carts on one deck than there are TT&L mushrooms. It will be acceptable to have adequate AFM limitations and/or placarding to assure the necessary level of safety. This guidance would be equally applicable if a galley or service compartment is located on a deck above the main deck. (Amendment 25-53)
(ii) Remote compartments should have adequate ventilation and conditioned air for all occupants. If the compartment is one in which occupants are working, such as a galley, more than normal ventilation and conditioned air should be supplied than that for a compartment in which the occupants are seated. If carbon dioxide (dry ice) is used in a compartment, additional ventilation may be necessary to demonstrate compliance with § 25.831(b)(2) for all regimes of operation; such as at the gate, taxi, takeoff, climb, cruise, hold and descent.
(Amendment 25-53)
(2) Paragraph (g)(l). Proximity or micro-switches are normally used to sense that the lift door or hatch is open or closed. These interlock switches should be located so that they cannot be easily or inadvertently overridden or deactivated. Special design considerations should be given to these switches to minimize the probability of them becoming damaged during normal use. (Amendment 25-53)
(3) Paragraph (g)(2). The emergency stop buttons are of prime importance and should be given special design considerations. These buttons should have absolute and complete priority over any other control, failure or lack of control. No matter what condition, failure or sequence of events that have occurred, operation of any emergency stop button should result in stopping of the lift without the ability to override from any other location. (Amendment 25-53)
483. AMENDMENT 25-110, Effective July 21, 2003.
a. Regulation.
For airplanes with a service compartment located below the main deck, which may be occupied during taxi or flight but not during takeoff or landing, the following apply:
(a) There must be at least two emergency evacuation routes, one at each end of lower deck service compartment or two having sufficient separation within each compartment, which could be used by each occupant or the lower deck service compartment to rapidly evacuate to the main deck under normal and emergency lighting conditions. The routes must provide for the evacuation of incapacitated persons, with assistance. The use of the evacuation routes may not be dependent on any powered device. The routes must be designed to minimize the possibility of blockage which might result from fire, mechanical or structural failure, or persons standing on top of or against the escape routes. In the event the airplane's main power system or compartment main lighting system should fail, emergency illumination for each lower deck service compartment must be automatically provided.
[(b) There must be a means for two-way voice communication between the flight deck and each lower deck service compartment, which remains available following loss of normal electrical power generating system.]
(c) There must be an aural emergency alarm system, audible during normal and emergency conditions, to enable crewmembers on the flight deck and at each required floor level emergency conditions, to enable crewmembers on the flight deck and at each required floor level emergency exit to alert occupants of each lower deck service compartment of an emergency situation.
(d) There must be a means, readily detectable by occupants of each lower deck service compartment, that indicates when seat belts should be fastened.
(e) If a public address system is installed in the airplane, speakers must be provided in each lower deck service compartment.
[(f) For each occupant permitted in a lower deck service compartment, there must be a forward or aft facing seat which meets the requirements of § 25.785(d) and must be able to withstand maximum flight loads when occupied.]
(g) For each powered lift system installed between a lower deck service compartment and the main deck for the carriage of persons or equipment, or both, the system must meet the following requirements:
(1) Each lift control switch outside the lift, except emergency stop buttons, must be designed to prevent the activation of the lift if the lift door, or the hatch required by paragraph (g)(3) of this section, or both are open.
(2) An emergency stop button, that when activated will immediately stop the lift, must be installed within the lift and at each entrance to the lift.
(3) There must be a hatch capable of being used for evacuating persons from the lift that is openable from the inside and outside the lift without tools, with the lift in any position.
b. Guidance.
(1) The following should be used for any installation regardless of certification basis:
(Amendment 25-53)
(i) The installation of a lower deck service compartment normally results in cart restraint locations on both the main and lower decks. At these locations, the carts are normally restrained by a fitting in the floor, commonly called a mushroom. There are two typical types of mushrooms. One is usually retractable, located in an aisle or passageway, and capable of restraining the cart for inflight load conditions only. The other mushroom is usually fixed, located in a galley, lift or cabinet, and generally capable of restraining the cart during taxi, takeoff, and landing (TT&L). If necessary, control of the number of carts allowed on each deck should be provided. For the TT&L condition, there should be enough TT&L mushrooms for each cart on the airplane. In order to be assured the carts can be taken to such a mushroom, there should be at least two independently powered and controlled lifts between the main and lower decks. If there are not at least two such lifts, it should be demonstrated by actual test that all carts can be transported up or down between decks. It is acceptable to transport the contents and cart separately by average flight attendants. If two such lifts are not installed and transportablity is not demonstrated, at any given time, there should not be more carts on one deck than there are TT&L mushrooms. It will be acceptable to have adequate AFM limitations and/or placarding to assure the necessary level of safety. This guidance would be equally applicable if a galley or service compartment is located on a deck above the main deck. (Amendment 25-53)
(ii) Remote compartments should have adequate ventilation and conditioned air for all occupants. If the compartment is one in which occupants are working, such as a galley, more than normal ventilation and conditioned air should be supplied than that for a compartment in which the occupants are seated. If carbon dioxide (dry ice) is used in a compartment, additional ventilation may be necessary to demonstrate compliance with § 25.831(b)(2) for all regimes of operation; such as at the gate, taxi, takeoff, climb, cruise, hold and descent.
(Amendment 25-53)
(2) Paragraph (g)(l). Proximity or micro-switches are normally used to sense that the lift door or hatch is open or closed. These interlock switches should be located so that they cannot be easily or inadvertently overridden or deactivated. Special design considerations should be given to these switches to minimize the probability of them becoming damaged during normal use. (Amendment 25-53)
(3) Paragraph (g)(2). The emergency stop buttons are of prime importance and should be given special design considerations. These buttons should have absolute and complete priority over any other control, failure or lack of control. No matter what condition, failure or sequence of events that have occurred, operation of any emergency stop button should result in stopping of the lift without the ability to override from any other location. (Amendment 25-53) 484 - 600. [RESERVED]
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487 SECTION 25.851 FIRE EXTINGUISHERS
601. REGULATION IN EFFECT AT ADOPTION OF PART 25.
a. Regulation.
(a) Hand fire extinguishers. For hand fire extinguishers the following apply:
(l) Each hand fire extinguisher must be approved.
(2) The types and quantities of each extinguishing agent used must be appropriate to the kinds of fires likely to occur where used.
(3) Each extinguisher for use in a personnel compartment must be designed to minimize the hazard of toxic gas concentrations.
(4) A readily accessible hand fire extinguisher must be available for use in each Class A or Class B cargo compartment.
(b) Built-in fire extinguishers. If a built-in fire extinguishing system is required -
(l) The capacity of each system, in relation to the volume of the compartment where used and the ventilation rate, must be adequate for any fire likely to occur in that compartment; and
(2) Each system must be installed so that -
(i) No extinguishing agent likely to enter personnel compartments will be hazardous to the occupants; and
(ii) No discharge of the extinguisher can cause structural damage.
b. Guidance.
(l) Paragraph (a)(1). Standards for approval. An approved type fire extinguisher includes those approved by the Underwriters' Laboratories, Inc., Factory Mutual Laboratories, Underwriters' Laboratories of Canada, or any other agency deemed qualified by the Administrator, or approved by the Administrator in accordance with the provisions of § 21.301.
(Amendment 25-0)
(2) Paragraphs (a)(2) and (a)(3). When selecting a hand held fire extinguisher for use in airplanes, consideration should be given to the most appropriate extinguishing agent for the type and location of fires likely to be encountered. At least one extinguisher appropriate for a Class A fire should be provided. Consideration should also be given to the extinguisher agent’s ratio of extinguishing ability to quantity required, toxicity, corrosive properties, freezing point, and to the
488 unit's gross weight, ease of operation, and maintenance requirements. Airplane hand held fire extinguishers using extinguisher agents having a rating in toxicity Group 4 or under should not be installed in airplanes for which an application for a type certificate was made on or after March 5, 1952. (Amendment 25-0) NOTE: The toxicity ratings listed by the Underwriters' Laboratories and the halon and freon number for some of the commonly known fire extinguisher chemicals are as follows:
Group Number Halon Number* Freon Number Bromochloromethane 3 1011 --- Bromotrifluoromethane 6 1301 13B1/FE1301 Carbon dioxide 5 --- --- Carbon tetrachloride 3 1040 --- Dibromodifluoromethane 4 1202 12B2 Methyl bromide 2 1001 --- * The halon number is defined as follows: the first number is the number of carbon atoms; the second, fluorine; the third, chlorine; and the fourth, bromine in the extinguisher agent’s chemical formula.
Some older transport category airplanes, due to their type certification bases, are not required to comply with § 25.851. For such airplanes, it is recommended that hand held fire extinguishers employing agents in toxicity Group 4 or higher be installed when renewing or replacing hand held fire extinguishers employing toxic agents. (Amendment 25-0)
(3) Paragraph (a)(2). Types of extinguishers. (Amendment 25-0)
(i) Carbon dioxide extinguishers. Carbon dioxide extinguishers are acceptable when the principal hazard is a Class B or Class C fire. Portable carbon dioxide installations should not exceed five lbs of agent per unit to ensure extinguisher portability and to minimize crew compartment carbon dioxide (CO2) concentrations. (Amendment 25-0)
(ii) Water extinguishers. Water extinguishers are acceptable when the principal hazard is a Class A fire and where a fire might smolder if attacked solely by such agents as CO2 or dry chemical. (Amendment 25-0)
(iii) Vaporizing liquid extinguishers. Vaporizing liquid type fire extinguishers are acceptable when the principal hazard is a Class B or Class C fire. (Amendment 25-0)
(iv) Dry chemical extinguishers. Dry chemical extinguishers are acceptable where the principal hazard is a Class B or Class C fire. The extinguisher should not be used in crew compartments because of interference with visibility during discharge and because of the possibility of the nonconductive powders being discharged on electrical contacts not otherwise involved. (Amendment 25-0)
(v) Specialized Dry Powder extinguishers for Class D fires. Solid materials in powder or granular form are designed to extinguish Class D combustible metal fires by crusting, smothering, or heat-transferring means. The recommendations of the manufacturer for use of those extinguishers should be followed because of the possible chemical reaction between the burning metal and the extinguishing agent. (Amendment 25-0) NOTE: Carbon dioxide is noncorrosive and will not injure food or fabric. Extinguishers must be winterized if they are to operate at temperatures below -40 °F. Approved unit capacity ranges upwards from two lbs. These extinguishers have only limited value for the extinguishment of a Class A fire, the action of the agent being to blanket the fire by excluding oxygen. Certain antifreeze agents may be corrosive. Approved extinguishers are either protected against freezing to -40 °F. or must be handled as any other unprotected water on the airplane. Technical Standard Order (TSO)-C19a covers a minimum l-3/8 quart capacity approved water extinguisher. Water extinguishers of the kinds currently on the market are not acceptable for flammable liquid or electrical fires.
Vaporizing liquid extinguisher agents are not normally corrosive to airplane structure and approved units will be satisfactorily protected against freezing to at least -40 °F. Up to the effective date of this guidance, no vaporizing liquid extinguisher with Underwriters' Laboratories toxicity rating higher than Group 4 is commercially available. Approved units have a minimum capacity of one quart. They are of only limited value for the extinguishment of Class A fires, having a cooling effect of about one-tenth that of water. When using dry chemical extinguishers the powder is nontoxic and noncorrosive, and approved units are protected against freezing to at least -40 °F. Minimum capacity of approved units is two lbs.
(4) Paragraph (a)(2). Class of fires. (Amendment 25-0)
(i) Class A fires. Fires in ordinary combustible materials where the quenching and cooling effects of quantities of water, or solutions containing large percentages of water, are of first importance. (Amendment 25-0)
(ii) Class B fires. Fires in flammable liquids, greases, etc., where a blanketing effect is essential. (Amendment 25-0)
(iii) Class C fires. Fires in electrical equipment, where the use of a nonconducting extinguishing agent is of first importance. (Amendment 25-0)
(iv) Class D fires. Fires which involve combustible metals, such as magnesium, titanium, zirconium, sodium, lithium, and potassium, and require extinguishing agents of the dry powder types. (Amendment 25-0)
(5) Paragraphs (a)(2) and (a)(3). For further guidance, refer to National Fire Protection Association (NFPA) 10, "Standards for Portable Fire Extinguishers." (Amendment 25-0)