(2) Paragraph (c). The intent of this requirement is to require additional hardware means to materially enhance occupant’s ability to locate the exits. Compliance with the floor proximity emergency escape path marking requirements of § 25.812(e) is also considered compliance with the requirements of this section. (Amendment 25-15)
(3) Paragraph (d). The signs required by paragraphs (d)(1), (2) and (3) are intended to be independent and serve different functions. However, certain cabin arrangements might permit a single sign to serve the functions of both paragraph (d)(1) and (3). If such an arrangement were presented, the sign should meet the contrast and brightness requirements of § 25.812(b)(1)(i) and should be in close proximity to the exits concerned. Compliance with both §§ 25.811(d)(1) and (3) is required regardless of the number of signs employed. (Amendment 25-32)
(4) Paragraph (d). Similar to the guidance immediately above, certain cabin arrangements and especially small cabin sizes might permit a single sign to serve both the locator and marker sign functions of paragraphs (d)(1) and (d)(2). If such a proposal was presented, the proposal should address all pertinent requirements of § 25.812, and it should be demonstrated that the sign satisfactorily performs both marker and locator sign functions. (Amendment 25-32)
(5) Paragraph (d)(2). Prior to Amendment 25-32, the exit marking sign of § 25.811(d)(2) was referred to as a locator sign in § 25.811(d)(2) for floor level exits. The locator sign requirement of § 25.811(d)(1) for floor level exits was introduced by Amendment 25-32. (Amendment 25-32)
(6) Paragraph (d). The signs required by paragraphs (d)(1) and (3) should be removed from the passenger compartment in mixed passenger/cargo arrangements if they indicate exits in the cargo compartment which are not accessible to passengers. For exits inaccessible in the cargo portion of the fuselage, the signs installed by this paragraph for passenger configurations may be left installed if they are not visible to the passengers. (Amendment 25-1)
(7) Paragraph (d)(2). The requirement for a sign next to each floor level exit is not satisfied by a sign mounted on the exit. The sign should remain visible whether or not the exit is open. In the case of an exit-mounted sign, the sign is removed when the exit is opened. This arrangement should not be employed. (Amendment 25-1)
(8) Paragraph (e). An exit opening handle where motion is in the plane perpendicular to the exit is not considered a rotary handle as defined in this paragraph. Therefore, the marking arrow specified is not required by this regulation. However, in order to provide an equivalent level of safety for this type of handle motion, markings appropriate to this type of handle should be provided. This should be documented in an Equivalent Safety Finding Issue Paper.
(Amendment 25-1)
(9) Paragraph (f). Exit bands are not required for "flightcrew only" exits or other emergency exits not in the sides of the fuselage. (Amendment 25-15)
(10) Paragraph (h). (Amendment 25-1)
(i) Guidance material for exterior colored bands around exits is provided in AC 20-47, “Exterior Colored Band Around Exits on Transport Airplanes,” dated 2/8/66.
(Amendment 25-1)
(ii) For airplanes that are convertible from passenger to mixed passenger/cargo arrangements, the exits unusable due to cargo blockage should be so marked. This can be indicated by a placard on or adjacent to the exit. The placard should provide obvious indication from the ground, to a rescue crew that the exit is not operable. No other change to the external markings is required. (Amendment 25-1)
(iii) If exits are deactivated, refer to § 25.807, Amendment 25-15, for guidance regarding deletion of markings for deactivated exits. (Amendment 25-1)
(11) Paragraphs (f)(1) and (2). The FAA issued policy memorandum ANM-03-115-04, dated April 2, 2003, and titled “Policy Statement on Exit Bands.” The policy is applicable to Amendment 25-88 for §§ 25.811(f)(1) and (2) as follows: (Amendment 25-1)
(i) The FAA has been asked if compliance with §§ 25.811(f)(1) and (2) can be found with the lower section of a two-inch colored band located a few-inches above the base of an exit. Metal door sills are often installed on the fuselage below floor-level exits to provide protection from impacts with loading equipment. If the band is located on the bottom edge of an exit, its color must be compared with the door sill color to determine compliance with § 25.811(f)(2). This requirement can result in a color scheme which is not desired by the operator. Note that painting the door sill is not considered a viable option since impacts with loading equipment cause the paint to scratch and wear away quickly. If the band is located a few-inches above the base of the exit, its color is compared with the door color below the band instead of the metal door sill. This results in more color options for operators to choose from in determining a desired color scheme. (Amendment 25-1)
(ii) The purpose of these bands is to assist rescue personnel in recognizing exits in the side of the fuselage. Section 25.811(f)(1) requires that a two-inch color band outline each passenger emergency exit in the side of the fuselage. Advisory Circular 20-47, paragraph 4b, indicates that a color band outlining an exit is considered to comply with applicable regulations whether the band is on the edge of the exit itself, on the fuselage surrounding the exit, or partially on both. Although this guidance indicates acceptance of bands located on the edge of the exit itself, the FAA considers that a band could be located a small distance away from the exit’s edge and still be considered to “outline” the exit as required by § 25.811(f)(1). The FAA finds that for floor-level exits the size of a Type II exit or larger, compliance can be found with the top and side sections of a band located a maximum of 2-inches away from the exit’s edge and the bottom section of a band located between 2-inches below and 3-inches above the exit’s edge. Figure 387-1 is a figure that demonstrates these boundaries. The bottom section of the band is allowed to be farther away from the exit’s edge than the other sides of the band to be consistent with past practices for exits with a door sill installed at their base. Although the band is not required to be
364 on the edge of the exit, it must be parallel to the exit’s edge in order to outline the exit as required by the rule. (Amendment 25-1) FIGURE 387-1 ACCEPTABLE COLOR BAND LOCATIONS FOR AN EXIT THE SIZE
OF A TYPE II EXIT OR LARGER
388 - 390. [RESERVED]
365 SECTION 25.812 EMERGENCY LIGHTING
391. Section 25.812 Did Not Exist Prior to Amendment 25-15.
392. AMENDMENT 25-15, Effective October 24, 1967.
a. Regulation.
(a) An emergency lighting system, independent of the main lighting system, must be installed which includes:
(1) Illuminated emergency exit marking and locating signs, sources of general cabin illumination, and interior lighting in emergency exit areas.
(2) Exterior emergency lighting.
(b) Each passenger exit sign and each exit locating sign must have white letters at least 1-inch high on a red background at least 2-inches high. These signs may be internally electrically illuminated, or self-illuminated by other than electrical means, with an initial brightness of at least 160 microlamberts. The colors may be reversed in the case of internally electrically illuminated signs if this will increase the illumination of the exit.
(c) General illumination in the passenger cabin must be provided so that when measured along the centerline of main passenger aisles at seat armrest height and at 40-inch intervals, the average illumination is not less than 0.05 foot-candle. A main passenger aisle is considered to extend along the fuselage from the most forward passenger emergency exit or cabin occupant seat, whichever is farther forward, to the most rearward passenger emergency exit or cabin occupant seat, whichever is farther aft.
(d) The floor of the passageway leading to each floor-level passenger emergency exit, between the main aisles and the exit openings, must be provided with illumination.
(e) The emergency lighting system is to be designed as follows:
(1) The lights must be operable manually from the flightcrew station and (if required by the operating rules of this chapter) from a point in the passenger compartment that is readily accessible to the flight attendant seat. Means are to be provided to safeguard against inadvertent operation of the manual controls.
(2) When armed or turned on, the lights must remain lighted or become lighted upon interruption (except an interruption caused by a vertical separation of the fuselage during crash landing) of the airplane's normal electric power.
(f) Exterior emergency lighting must be provided at each overwing exit so that the illumination is -
(1) Not less than 0.02 foot-candle (measured on a plane parallel to the surface) on a 2-square-foot area where an evacuee is likely to make his first step outside the cabin:
(2) Not less than 0.05 foot-candle (measured normal to the direction of the incident light) for a minimum width of 2 feet along the 30 percent of the slip-resistant escape route required in § 25.803(e) that is farthest from the exit; and
(3) Not less than 0.02 foot-candle on the ground surface with the landing gear extended (measured on a horizontal plane) where an evacuee using the established escape route would normally make first contact with the ground.
(g) The means required in §§ 25.809(f)(1) and (h) to assist the occupants in descending to the ground must be illuminated so that the deployed assist means is visible from the airplane.
(1) If the assist means is illuminated by exterior emergency lighting, it must provide -
(i) Illumination at each overwing emergency exit of not less than 0.02 foot-candle on the ground surface with the landing gear extended (measured in a horizontal plane) where an evacuee using the established escape route would normally make first contact with the ground; and
(ii) Illumination at each non-overwing emergency exit, of not less than 0.03 footcandle (measured normal to the direction of the incident light) at the ground end of the assist means and, for each non-over-wing exit in the side of the fuselage, over a spherical surface 10 degrees to either side of the center of the assist means and from 30 degrees above to 5 degrees below the 45 degree position of the assist means.
(2) If the assist means is self-illuminated, the lighting provisions -
(i) May not be adversely affected by stowage; and
(ii) Must provide sufficient ground surface illumination so that obstacles at the end of the assist means are clearly visible to evacuees.
(h) The energy supply to each emergency lighting unit must provide the required level of illumination for at least 10 minutes at the critical ambient conditions after emergency landing.
(i) If storage batteries are used as the energy supply for the emergency lighting system, they may be recharged from the airplane's main electric power system provided that the charging circuit is designed to preclude inadvertent battery discharge into charging circuit faults.
(j) Components of the emergency lighting system, including batteries, wiring relays, lamps, and switches, must be capable of normal operation after having been subjected to the inertia forces listed in § 25.561(b).
(k) The emergency lighting system must be designed so that after any single vertical separation of the fuselage during crash landing -
(1) Not more than 25 percent of all electrically illuminated emergency lights required by this section are rendered inoperative in addition to the lights that are directly damaged by the separation;
(2) Each electrically illuminated exit sign required under § 25.811(d)(2) remains operative exclusive of those that are directly damaged by the separation; and
(3) At least one required exterior emergency exit light for each side of the airplane remains operative exclusive of those that are directly damaged by the separation.
b. Guidance.
(1) Paragraph (b). Advisory Circular 20-38A, “Measurement of Cabin Interior Emergency Illumination in Transport Airplanes,” dated 2/8/66, provides guidance material for the minimum measurements required by this paragraph. (Amendment 25-15)
(2) Paragraph (c). (Amendment 25-15)
(i) Required illumination levels for main aisles also apply to cross aisles (later incorporated by Amendment 25-32) that are required to meet § 25.807(a)(7)(v). Cross aisles that are in excess of those required need not be provided with emergency lighting. (Amendment 25-
15)
(ii) When measuring the illumination levels required by this paragraph, the interior color scheme (sidewalls, seat covers, floor covering, etc.) should be evaluated for its reflective contribution to the illumination level. This may be accomplished by negating the contribution of reflected light and demonstrating the minimum illumination levels independent of reflected light. If the reflective contribution is known, subsequent interiors of different reflectivity may be analyzed to show the effect on illumination levels is not detrimental. (Amendment 25-15)
(3) Paragraph (e). Normal electrical power is interpreted to mean the engine driven generators. (Amendment 25-15)
(4) Paragraph (f)(1). The illumination level at an overwing escape route where the evacuee would take his first step outside the airplane may be measured with the exit unobstructed. It is not necessary to consider an evacuee standing in the exit opening when measuring illumination levels. Transient blocking of the wing contact area illumination as an
368 evacuee passes through the exit is acceptable provided no adverse effects are observed during the demonstration required by § 25.803(c). (Amendment 25-15)
(5) Paragraph (g). Illumination of the overwing escape path or an assist means at any exit should be automatically activated as part of the airplane emergency lighting system, or by the action of opening the exit. The required exterior lighting at an exit may not be dependent on the operation of another exit. (Amendment 25-15)
(6) Paragraph (h). When the airplane is exposed to the critical minimum and maximum ambient temperatures such that the airplane is in equilibrium, the airplane environmental systems may be used to condition the airplane prior to boarding passengers. The temperature of the power supplies may be determined following a reasonable conditioning period to obtain operation voltage when the airplane is at the critical outside ambient temperature. The illumination may then be measured assuming ten-minute operation from these initial conditions.
If an applicant is unable to furnish what initial conditions are, it is acceptable to use Radio Technical Commission for Aeronautics Document No. RTCA/DO-160B, titled "Environmental Conditions and Test Procedures for Airborne Equipment," for low and high temperature tests.
An additional alternate set of satisfactory environmental conditions may be found in AC 25.812-1A, “Floor Proximity Emergency Escape Path Marking,” dated 5/22/89.
(Amendment 25-15)
(7) Paragraph (k). A transverse separation is considered to occur at any fuselage station, irrespective of the perceived likelihood that a separation could occur there. “Separation” in this context refers to all degrees of fuselage separation such that the emergency lighting system is interrupted, and not just separations that result in two distinct segments of fuselage.
(Amendment 25-15)
(8) Paragraph (k)(1). This paragraph is based on the number of electrically illuminated lights required to meet the illumination levels of this section. Exit signs which are not used to contribute to cabin illumination and subsystems provided in accordance with paragraph (g)(2) do not apply to this paragraph. However, an applicant should not be penalized for providing lights in excess of the number required. (Amendment 25-15)
(9) Paragraph (k)(2). “Directly damaged,” as used in this paragraph, refers to a sign that is located at the same station as a transverse fuselage separation, or between the frames bounding the separation location, and therefore rendered inoperative. The sign is also considered inoperative if the separation occurs at the same station as any part of the power supply. The sign should remain operative unless it is “directly damaged” or the separation renders the exit unopenable. Therefore, the power supply should be located at a station between the frames that make up the exit, or in the case of a sign beside the exit, the power supply may also be at the same fuselage station as any part of the sign. (Amendment 25-15)
393. AMENDMENT 25-28, Effective September 25, 1971.
a. Regulation.
(a) An emergency lighting system, independent of the main lighting system, must be installed which includes:
(1) Illuminated emergency exit marking and locating signs, sources of general cabin illumination, and interior lighting in emergency exit areas.
(2) Exterior emergency lighting.
(b) Each passenger exit sign and each exit locating sign must have white letters at least 1-inch high on a red background at least 2-inches high. These signs may be internally electrically illuminated, or self-illuminated by other than electrical means, with an initial brightness of at least 160 microlamberts. The colors may be reversed in the case of internally electrically illuminated signs if this will increase the illumination of the exit.
(c) General illumination in the passenger cabin must be provided so that when measured along the centerline of main passenger aisles at seat armrest height and at 40-inch intervals, the average illumination is not less than 0.05 foot-candle. A main passenger aisle is considered to extend along the fuselage from the most forward passenger emergency exit or cabin occupant seat, whichever is farther forward, to the most rearward passenger emergency exit or cabin occupant seat, whichever is farther aft.
(d) The floor of the passageway leading to each floor-level passenger emergency exit, between the main aisles and the exit openings, must be provided with illumination.
[(e) Except for subsystems provided in accordance with paragraph (g) of this section that serve no more than one assist means, are independent of the airplane's main emergency lighting system, and are automatically activated when the assist means is deployed, the emergency lighting system must be designed as follows:]
(1) The lights must be operable manually from the flight crew station and (if required by the operating rules of this chapter) from a point in the passenger compartment that is readily accessible to a normal flight attendant seat. Means must be provided to safeguard against inadvertent operation of the manual controls.
(2) When armed or turned on, the lights must remain lighted or become lighted upon interruption (except an interruption caused by a vertical separation of the fuselage during crash landing) of the airplane's normal electric power.
(f) Exterior emergency lighting must be provided at each overwing exit so that the illumination is-
(1) Not less than 0.02 foot-candle (measured on a plane parallel to the surface) on a 2-square-foot area where an evacuee is likely to make his first step outside the cabin;
(2) Not less than 0.05 foot-candle (measured normal to the direction of the incident light) for a minimum width of 2 feet along the 30 percent of the slip-resistant escape route required in § 25.803(e) that is farthest from the exit; and
(3) Not less than 0.02 foot-candle on the ground surface with the landing gear extended (measured on a horizontal plane) where an evacuee using the established escape route would normally make first contact with the ground.
(g) The means required in § 25.809 (f)(1) and (h) to assist the occupants in descending to the ground must be illuminated so that the deployed assist means is visible from the airplane.
(1) If the assist means is illuminated by exterior emergency lighting, it must provide-
(i) Illumination at each overwing emergency exit of not less than 0.02 foot-candle on the ground surface with the landing gear extended (measured in a horizontal plane) where an evacuee using the established escape route would normally make first contact with the ground; and
(ii) Illumination at each non-over-wing emergency exit, of not less than 0.03 footcandle (measured normal to the direction of the incident light) at the ground end of the assist means and, for each non-over-wing exit in the side of the fuselage, over a spherical surface 10° to either side of the center of the assist means and from 30° above the 45° position of the assist means.
[(2) If the emergency lighting subsystem illuminating the assist means serves no other assist means, is independent of the airplane's main emergency lighting system, and is automatically activated when the assist means is deployed, the lighting provisions-]
(i) May not be adversely affected by stowage; and
(ii) Must provide sufficient ground surface illumination so that obstacles at the end of the assist means are clearly visible to evacuees.
(h) The energy supply to each emergency lighting unit must provide the required level of illumination for at least 10 minutes at the critical ambient conditions after emergency landing.
(i) If storage batteries are used as the energy supply for the emergency lighting system, they may be recharged from the airplane's main electric power system:
Provided, That, the charging circuit is designed to preclude inadvertent battery discharge into charging circuit faults.
(j) Components of the emergency lighting system, including batteries, wiring relays, lamps, and switches must be capable of normal operation after having been subjected to the inertia forces listed in § 25.561(b).
(k) The emergency lighting system must be designed so that after any single vertical separation of the fuselage during crash landing-
(1) Not more than 25 percent of all electrically illuminated emergency lights required by this section are rendered inoperative, in addition to the lights that are directly damaged by the separation;
(2) Each electrically illuminated exit sign required under § 25.811(d)(2) remains operative exclusive of those that are directly damaged by the separation; and
(3) At least one required exterior emergency exit light for each side of the airplane remains operative exclusive of those that are directly damaged by the separation.
b. Guidance.
(1) Paragraph (b). Advisory Circular 20-38A, “Measurement of Cabin Interior Emergency Illumination in Transport Airplanes,” dated 2/8/66, provides guidance material for the minimum measurements required by this paragraph. (Amendment 25-15)
(2) Paragraph (c). (Amendment 25-15)
(i) Required illumination levels for main aisles also apply to cross aisles (later incorporated by Amendment 25-32) that are required to meet § 25.807(a)(7)(v). Cross aisles that are in excess of those required need not be provided with emergency lighting. (Amendment 25-
15)
(ii) When measuring the illumination levels required by this paragraph, the interior color scheme (sidewalls, seat covers, floor covering, etc.) should be evaluated for its reflective contribution to the illumination level. This may be accomplished by negating the contribution of reflected light and demonstrating the minimum illumination levels independent of reflected light. If the reflective contribution is known, subsequent interiors of different reflectivity may be analyzed to show the effect on illumination levels is not detrimental. (Amendment 25-15)
(3) Paragraph (e). Normal electrical power is interpreted to mean the engine driven generators. (Amendment 25-15)
(4) Paragraph (f)(1). The illumination level at an overwing escape route where the evacuee would take his first step outside the airplane may be measured with the exit unobstructed. It is not necessary to consider an evacuee standing in the exit opening when measuring illumination levels. Transient blocking of the wing contact area illumination as an evacuee passes through the exit is acceptable provided no adverse effects are observed during the demonstration required by § 25.803(c). (Amendment 25-15)
(5) Paragraph (g). Illumination of the overwing escape path or an assist means at any exit should be automatically activated as part of the airplane emergency lighting system, or by the action of opening the exit. The required exterior lighting at an exit may not be dependent on the operation of another exit. (Amendment 25-15)
(6) Paragraph (h). When the airplane is exposed to the critical minimum and maximum ambient temperatures such that the airplane is in equilibrium, the airplane environmental systems may be used to condition the airplane prior to boarding passengers. The temperature of the power supplies may be determined following a reasonable conditioning period to obtain operation voltage when the airplane is at the critical outside ambient temperature. The illumination may then be measured assuming ten-minute operation from these initial conditions.
If an applicant is unable to furnish what initial conditions are, it is acceptable to use Radio Technical Commission for Aeronautics Document No. RTCA/DO-160B, titled "Environmental Conditions and Test Procedures for Airborne Equipment," for low and high temperature tests.
An additional alternate set of satisfactory environmental conditions may be found in AC 25.812-1A, “Floor Proximity Emergency Escape Path Marking,” dated 5/22/89.
(Amendment 25-15)
(7) Paragraph (k). A transverse separation is considered to occur at any fuselage station, irrespective of the perceived likelihood that a separation could occur there. “Separation” in this context refers to all degrees of fuselage separation such that the emergency lighting system is interrupted, and not just separations that result in two distinct segments of fuselage.
(Amendment 25-15)
(8) Paragraph (k)(1). This paragraph is based on the number of electrically illuminated lights required to meet the illumination levels of this section. Exit signs which are not used to contribute to cabin illumination and subsystems provided in accordance with paragraph (g)(2) do not apply to this paragraph. However, an applicant should not be penalized for providing lights in excess of the number required. (Amendment 25-15)
(9) Paragraph (k)(2). “Directly damaged,” as used in this paragraph, refers to a sign that is located at the same station as a transverse fuselage separation, or between the frames bounding the separation location, and therefore rendered inoperative. The sign is also considered inoperative if the separation occurs at the same station as any part of the power supply. The sign should remain operative unless it is “directly damaged” or the separation renders the exit unopenable. Therefore, the power supply should be located at a station between the frames that make up the exit, or in the case of a sign beside the exit, the power supply may also be at the same fuselage station as any part of the sign. (Amendment 25-15)
394. AMENDMENT 25-32, Effective May 1, 1972.
a. Regulation.
[(a) An emergency lighting system, independent of the main lighting system, must be installed. However, the sources of general cabin illumination may be common to both the emergency and the main lighting systems if the power supply to the emergency lighting system is independent of the power supply to the main lighting system. The emergency lighting system must include:]
(1) Illuminated emergency exit marking and locating signs, sources of general cabin illumination, and interior lighting in emergency exit areas.
(2) Exterior emergency lighting.
[(b) Emergency exit signs-
(1) For airplanes that have a passenger seating configuration, excluding pilot seats, of 10 seats or more must meet the following requirements:
(i) Each passenger emergency exit locator sign required by § 25.811 (d)(1) and each passenger emergency exit marking sign required by § 25.811 (d)(2) must have red letters at least 1½-inches high on an illuminated white background, and must have an area of at least 21 square-inches excluding the letters. The lighted background-toletter contrast must be at least 10:1. The letter height to stroke-width ratio may not be more than 7:1 nor less than 6:1. These signs must be internally electrically illuminated with a background brightness of at least 25 foot-lamberts and high-to-low background contrast no greater than 3:1.
(ii) Each passenger emergency exit sign required by § 25.811 (d)(3) must have red letters at least 1½-inches high on a white background having an area of at least 21 square-inches excluding the letters. These signs must be internally electrically illuminated or self-illuminated by other than electrical means and must have an initial brightness of at least 400 microlamberts. The colors may be reversed in the case of a sign that is self-illuminated by other than electrical means.
(2) For airplanes that have a passenger seating configuration, excluding pilot seats, of nice seats or less, that are required by § 25.811 (d)(1), (2), and (3) must have red letters at least 1-inch high on a white background at least 2-inches high. These signs may be internally electrically illuminated, or self-illuminated by other than electrical means, with an initial brightness of at least 160 microlamberts. The colors may be reversed in the case of a sign that is self-illuminated by other than electrical means.
(c) General illumination in the passenger cabin must be provided so that when measured along the centerline of main passenger aisle(s), and cross aisle(s) between