225 remember for those situations where the passageway is canted to meet the projected cross aisles, which are discussed below. (Amendment 25-15)
(ii) Additionally, where more than one main aisle is provided, § 25.807(a)(7)(v) requires that there must be an unobstructed 20-inch wide cross aisle, leading directly to the exit passageways. This cross aisle is considered to extend from the inboard side of one main aisle to the inboard side of the other main aisle. The required cross aisle does not have to be straight nor does it have to be normal to the main aisles. (Amendment 25-15)
(iii) For the case where the exit is located at the end of the passenger cabin and there are only two approach paths to the exit (the main aisle from one direction and the cross aisle), the 36-inch wide passageway should extend from the exit to the point where the evacuee flows from the main aisle and cross aisle merge to ensure the dual lane flow can be maintained.
(Amendment 25-15)
(iv) In the other case, where the exit is not located at the end of the cabin and there are three approach paths (the main aisle from two directions and the cross aisle) to the exit, the 20-inch width of the cross aisle should be within the 36-inch width of the passageway when the cross aisle is projected normal to the main aisle. Some portion of the 20-inch wide cross aisle should be within the width of the projected door opening. (Amendment 25-15)
(v) If the boundaries of any of the aforementioned passageways, aisles or cross aisles are formed by passenger seats, ensure that the minimum requirements are met with the seat in the most adverse condition that is not prohibited by design. (Amendment 25-15)
(vi) Door and cross aisle visibility is also of prime importance when evaluating the safety level of an exit configuration. This is especially true when the cross aisle is displaced forward or aft from the exit opening or when a pair of exits are not directly across the airplane from each other. The configuration should provide a view across the airplane such that the exit on the other side is readily identifiable. Identification of the opposite exit may be via the exit marking sign, the exit opening handle and related markings or when the field of vision provided allows visual perception of sufficient detail to recognize that there is an exit across the airplane.
This identification should be evaluated when standing at the center of the opposite exit. In certain cases, additional exit locator signs may be necessary to direct evacuees to the opposite exit. (Amendment 25-15)
(5) Paragraph (a). Exits may be “derated” in accordance with the requirements of a smaller type; that is, exits may not only be oversized, the interior may be reconfigured to specifically derate an exit that has previously been qualified as a larger type. In order to preclude the appearance of the exit being unusable, the following additional considerations have been found acceptable: (Amendment 25-15)
(i) Type A to Type I: Only seats may encroach into the projected exit opening, no more than 12-inch cumulative. A 24-inch passageway should be provided, and seats may not breakover into this passageway or into the assist space. The operating handle should be visible from the aisle. (Amendment 25-15)
(ii) Type A to Type III: A 24-inch passageway should be provided, and seats may not breakover into this passageway. The operating handle should be visible from the aisle.
(Amendment 25-15)
(iii) Type I to Type III: A 13-inch passageway is required when the passageway is bordered by seats, or by a seat and a wall. A 20-inch passageway should be provided when the passageway is bordered by walls and should be within the projected opening of the exit. The required Type III opening should be unobstructed inboard for the width of one passenger seat place. The operating handle should be visible from the aisle. (Amendment 25-15)
(6) Paragraph (c). Although these rules do not prescribe longitudinal distance between exits, they do specify passenger seating configurations matched to exit pairs in which factors of uniform exit distribution, accessibility and location to enhance effective egress must be considered. The uniform exit distribution should consider the situation where the exits on one side of the fuselage are unusable due to fire or other factors. Refer to AC 25.807-1, “Uniform Distribution of Exits,” dated 8/13/90 for additional guidance on this subject. (Amendment 25-15)
(7) Paragraph (c)(6). Seats that have dual approval for occupancy by either crew/observers and passengers will be included in the passenger seating configuration for determining the required number of exits. Regarding removal of excess exits, regardless of airplane certification basis, the following criteria applies: (Amendment 25-15)
(i) All interior and exterior exit signs, markings, and lighting pertaining to the deactivated exits must be removed. There must be no recognizable evidence of the deactivated exits, visible to occupants of the cabin. However, the exterior door outline and handle need not be obscured. (Amendment 25-15)
(ii) The modification which deactivates and obscures the exits must be approved through issuance of an amendment to the Type Certificate (TC) or Supplemental Type Certificate (STC) by the Manager, Aircraft Certification Office having jurisdiction over the project, and the airplane cabin, as modified, must remain in compliance with the certification basis of the model. (Amendment 25-15)
(iii) Also refer to AC 20-60, “Accessibility to Excess Emergency Exits,” dated 7/18/68. (Amendment 25-15)
(8) Paragraph (c). An airplane with a Type I sized exit located in the forward left-hand side of the fuselage, a pair of Type III exits in the middle, and a Type I sized exit located in the aft right-hand side of the fuselage should be limited to a maximum passenger seating capacity of 70, because of concerns with oversized dead-end zones if either the left- or right-side exits are unusable. (Amendment 25-0)
(9) Paragraph (c). An airplane with a pair of exits forward in the fuselage with the left one Type I sized and the right one Type III sized, and a pair of exits in the aft end of the fuselage with the left one Type III sized and the right one Type I sized may be approved for passenger
227 seating capacities up to 79. If an emergency evacuation demonstration is required, then either the left-side or right-side exits should be selected so as not to unduly penalize this well-balanced arrangement or to make a radical departure from all previous demonstrations. Refer to figure 323-1. (Amendment 25-0)
(10) Paragraphs (c) and (d). When establishing the maximum capacity to be listed on the type data sheet, consideration should be given to all relevant parameters. For example, if the exit-limited passenger capacity as defined in § 25.807(c) has not been substantiated by compliance with the evacuation demonstration requirements of § 25.803, the data sheet should reflect the evacuation limit and not the exit limit. Other limiting factors include, but are not limited to, structural capability, seating density (uniform distribution of exits), or ditching exits.
The maximum passenger capacity is also limited by the ditching requirements of § 25.807(d) whether certification for ditching is requested or not. In any case, the data sheet should not list a capacity for which the airplane is not capable. When the type data sheet limit is not the § 25.807(c) exit limit, an additional note, which briefly describes the reason for the limit, is appropriate. (Amendment 25-0)
(11) Paragraph (d). All transport category airplanes must have ditching exits whether or not ditching certification was requested. Actually, this guidance has been in effect since April 9, 1957, as reflected in Amendment 4b-5, "Emergency Evacuation Provisions," to CAR 4b.
(Amendment 25-0).
(12) Paragraph (c) and (d). Flight attendants are considered part of the crew and are not included in the passenger seating capacity mentioned in § 25.807(c) and (d). (Amendment 25-0)
(13) Paragraph (c) and (d). An airplane design is determined to be eligible for a certain passenger seating complement which is commensurate with meeting all of the relevant portions of § 25.807. That is, in addition to meeting table of § 25.807(c)(1), the eligibility complement is also governed by the ditching requirements of § 25.807(d), whether certification for ditching is requested or not. (Amendment 25-0)
(14) Paragraph (d)(2). The wording “a passenger seating configuration, excluding pilot seats, of 10 seats or more,” which was promulgated with the intent of being consistent with Amendment 23-10 to part 23, does not directly address seats intended for use by observers or flight attendants. Seats approved for use by observers or flight attendants are not included in the passenger seating configuration. Seats that have dual approval for occupancy by either crew/observers or passengers will be included in the passenger seating configuration.
(Amendment 25-32)
(15) Paragraph (d)(3). The wording “a passenger seating configuration, excluding pilot seats, of 35 seats or less,” which was promulgated with the intent of being consistent with Amendment 23-10 to part 23, does not directly address seats intended for use by observers or flight attendants. Seats approved for use by observers or flight attendants are not included in the passenger seating configuration. Seats that have dual approval for occupancy by either crew/observers or passengers will be included in the passenger seating configuration.
(Amendment 25-32)
324. AMENDMENT 25-39, Effective February 10, 1977.
a. Regulation.
(a) Type and location. For the purpose of this Part, the types and locations of exits are as follows:
(1) Type I. This type must have a rectangular opening of not less than 24 inches wide by 48 inches high, with corner radii not greater than on-third the width of the exit. Type I exits must be floor level exits.
(2) Type II. This type must have a rectangular opening of not less than 20 inches wide by 44 inches high, with corner radii not greater than one-third the width of the exit. Type II exits must be floor level exits unless located over the wing, in which case they may not have a step-up inside the airplane of more than 10 inches nor a stepdown outside the airplane of more than 17 inches.
(3) Type III. This type must have a rectangular opening of not less than 20 inches wide by 36 inches high, with corner radii not greater than one-third the width of the exit, and with a step-up inside the airplane of not more than 20 inches. If the exit is located over-the-wing the step-down outside the airplane may not exceed 27 inches.
(4) Type IV. This type must have a rectangular opening of not less than 19 inches wide by 26 inches high, with corner radii not greater than one-third the width of the exit, located over the wing, with a step-up inside the airplane of not more than 29 inches and a stepdown outside the airplane of not more than 36 inches.
(5) Ventral. This type is an exit from the passenger compartment through the pressure shell and the bottom fuselage skin. The dimensions and physical configuration of this type of exit must allow at leas the same rate of egress as a Type I with the airplane in the normal ground attitude, with landing gear extended.
(6) Tail cone. This type is an aft exit form the passenger compartment through the pressure shell and through an openable cone of the fuselage aft of the pressure shell.
The means of opening the tail cone must be simple and obvious, and must employ a single operation.
(7) Type A. An emergency exit may be designated as a Type A exit if the following criteria are met:
(i) There must be a rectangular opening not less than 42 inches wide by 72 inches high, with corner radii not greater than one-sixth of the width of the exit.
(ii) It must be a floor level exit.
(iii) Unless there are two or more main (fore and aft) aisles, the exit must be located so that there is passenger flow along the main aisle to that exit from both the forward and aft direction.
(iv) There must be an unobstructed passageway at least 36 inches wide leading from each exit to the nearest main aisle.
(v) If two or more main aisles are provided, there must be unobstructed cross aisles at least 20 inches wide between main aisles. There must be a cross aisle leading directly to each passageway between the exit and the nearest main aisle.
(vi) There must be at least one seat adjacent to each such exit that could be occupied by a flight attendant.
(vii) Adequate assist space next to each Type A exit must be provided at each side of the passageway, to allow the crewmember(s) to assist in the evacuation of passengers without reducing the unobstructed width of the passageway below that required by subdivision (iv) of this subparagraph.
(viii) At each non-over-wing exit there must be installed a slide capable of carrying simultaneously two parallel lines of evacuees.
(ix) Each overwing exit having a stepdown must have an assist means unless the exit without an assist means can be shown to have a rate of passenger degrees at least equal to that of the same type of non-over-wing exit. If an assist means is required it must be automatically deployed, and automatically erected, concurrent with the opening of the exit and self-supporting within 10 seconds.
Stepdown distance as used in this section means the actual distance between the bottom of the required opening and a usable foothold, extending out from the fuselage, that is large enough to be effective without searching by sight or feel.
(b) Accessibility. Each required passenger emergency exit must be accessible to the passengers and located where it will afford the most effective means if passenger evacuation. Openings larger than those specified in this section, whether or not of rectangular shape, may be used if-
(1) The specified rectangular opening can be inscribed within the opening; and
(2) The base of the inscribed rectangular opening meets the specified step-up and step-down heights.
(c) Passenger emergency exits. The prescribed exits need not be diametrically opposite each other nor identical in size and location on both sides. They must be distributed as uniformly as practicable taking into account passenger distribution. If only one floor level exit per side is prescribed, and the airplane does not have a tail
230 cone or ventral emergency exit, the floor level exits must be in the rearward part of the passenger compartment, unless another location affords a more effective means of passenger evacuation. Where more than one floor level exit per side is prescribed, at least one floor level exit per side must be located near each end of the cabin, except that this provision does not apply to combination cargo/passenger configuration.
Exits must be provided as follows:
(1) Except as provided in subparagraphs (2) through (6) of this paragraph, the number and type of passenger emergency exits must be in accordance with the following table:
Emergency exits for each side of the fuselage Passenger seating configuration (crewmember eats on included) Type I Type II Type III Type IV 1 through 9---- ------- ------ ------- 1 10 through 19--- ------- ------ 1 ------ 20 through 39--- ------- 1 1 ------ 40 through 79--- 1 ------ 1 ------ 80 through 109-- 1 ------ 2 ------ 110 through 139- 2 ------ 1 ------ 140 through 179- 2 ------ 2 ------
(2) An increase in the passenger seating configuration above the maximum permitted under subparagraph (1) of this paragraph but not to exceed a total of 299 seats may be allowed in accordance with the following table for each additional pair of emergency exits in excess of the minimum number prescribed in subparagraph (1) of this paragraph for 179 passenger seats;
[Additional emergency exits (each side of fuselage) Increase in passenger seating configuration allowed Type A ------------------------ 110 Type I ------------------------- 45 Type II ------------------------ 40 Type III ------------------------ 35]
(3) For passenger seating configurations in excess of 299 seats, each emergency exit in the side of the fuselage must be either a Type A or Type I. [A passenger seating configuration of 110 seats is allowed for each pair of Type I exits.]
(4) If a passenger ventral or tail cone exit is installed and can be shown to allow a rate of egress at least equivalent to that of a Type III exit with the airplane in the most adverse exit opening condition because of the collapse of one or more legs of the
231 landing gear, an increase in the passenger seating configuration beyond the limits specified in subparagraph (1), (2), or (3) of this paragraph may be allowed as follows:
(i) For a ventral exit, 12 additional passenger seats.
(ii) For a tail cone exit incorporating a floor level opening of not less than 20 inches wide by 60 inches high, with corner radii not greater than one-third the width of the exit, in the pressure shell and incorporating an approved assist means in accordance with § 25.809(f)(1), 25 additional passenger seats.
(iii) For a tail cone exit incorporating an opening in the pressure shell which is at least equivalent to a Type III emergency exit with respect to dimensions, step-up and step-down distance, and with the top of the opening not less than 56 inches from the passenger compartment floor, 15 additional passenger seats.
(5) For airplanes on which the vertical location of the wing does not allow the installation of overwing exits, an exit of at least the dimensions of a Type III exit must be installed instead of each Type IV exit required by subparagraph (1) of this paragraph.
(6) Each emergency exit in the passenger compartment in excess of the minimum number of required emergency exits must meet the applicable requirements of §§ 25.809 through 25.812, and must be readily accessible.
(d) Ditching emergency exits for passengers. Ditching emergency exits must be provided in accordance with the following requirements, unless the emergency exits required by paragraph (c) of this section already meet them:
(1) For airplanes that have a passenger seating configuration, excluding pilots seats, of nine seats or less, one exit above the waterline in each side of the airplane, meeting at least the dimensions of a Type IV exit.
(2) For airplanes that have a passenger seating configuration, excluding pilots seats, of 10 seats or more, one exit above the waterline in a side of the airplane, meeting at least the dimensions of a Type III exit, for each unit (or part of a unit) of 35 passenger seats, but no less than two such exits side of the airplane. However, where it has been shown through analysis, ditching demonstrations, or any other tests found necessary by the Administrator, that the evacuation capability of the airplane during ditching is improved by the use of larger exits, or by other means, the passenger seat/exit ratio may be increased.
(3) If side exits cannot be above the waterline, the side exits must be replaced by an equal number of readily accessible overhead hatches of not less than the dimensions of a Type III exit except that, for airplanes with a passenger configuration excluding
232 pilots seats, of 35 seats or less, the two required Type III side exits need be replaced by only one overhead hatch.
b. Guidance.
(1) The equivalency to that required by the regulations of nonstandard exits or arrangements may be determined by use of the Latin-Square test procedure. Refer to Appendix 4, which was derived from Notice FS 8110.12, “Test Procedure for Evaluating Non-Standard Exits for Transport Category Airplanes,” dated May 21, 1964. (Amendment 25-0)
(2) An “exit pair” consists of two exits of the same type, one in each side of the fuselage. The exits need not be the same size, nor do they have to be directly opposite each other. As long as the exits on both sides of the fuselage are uniformly distributed with respect to the passenger seating arrangement, a pair need not be the two exits that are physically closest to each other. (Amendment 25-0)
(3) Paragraph (a)(3). Type III exits were not restricted to overwing locations. Further, Type IV exits were restricted to airplanes that have a passenger seating capacity of nine or less, as reflected in the § 25.807(c)(l) table. Refer to figure 324-1. (Amendment 25-32) FIGURE 324-1 AIRPLANE CONFIGURATION
(4) Paragraph (a)(7)(iv) and (v). These two paragraphs define the requirements for passageways to Type A exits and cross aisles in two aisle airplanes. These provide sufficient access for two lines of evacuees to egress simultaneously: (Amendment 25-15)
(i) In order to achieve the dual lane flow of evacuees, § 25.807(a)(7)(iv) requires an unobstructed 36-inch width passageway that leads to the exit from the outboard side of the adjacent main aisle. It should not, however, encroach upon the crewmember assist spaces that are required on both sides of the exit by § 25.807(a)(7)(vii). This is particularly important to remember for those situations where the passageway is canted to meet the projected cross aisles, which are discussed below. (Amendment 25-15)
(ii) Additionally, where more than one main aisle is provided, § 25.807(a)(7)(v) requires that there must be an unobstructed 20-inch wide cross aisle, leading directly to the exit passageways. This cross aisle is considered to extend from the inboard side of one main aisle to the inboard side of the other main aisle. The required cross aisle does not have to be straight nor does it have to be normal to the main aisles. (Amendment 25-15)
(iii) For the case where the exit is located at the end of the passenger cabin and there are only two approach paths to the exit (the main aisle from one direction and the cross aisle), the 36-inch wide passageway should extend from the exit to the point where the evacuee flows from the main aisle and cross aisle merge to ensure the dual lane flow can be maintained.
(Amendment 25-15)
(iv) In the other case, where the exit is not located at the end of the cabin and there are three approach paths (the main aisle from two directions and the cross aisle) to the exit, the 20-inch width of the cross aisle should be within the 36-inch width of the passageway when the cross aisle is projected normal to the main aisle. Some portion of the 20-inch wide cross aisle should be within the width of the projected door opening. (Amendment 25-15)
(v) If the boundaries of any of the aforementioned passageways, aisles or cross aisles are formed by passenger seats, ensure that the minimum requirements are met with the seat in the most adverse condition that is not prohibited by design. (Amendment 25-15)
(vi) Door and cross aisle visibility is also of prime importance when evaluating the safety level of an exit configuration. This is especially true when the cross aisle is displaced forward or aft from the exit opening or when a pair of exits are not directly across the airplane from each other. The configuration should provide a view across the airplane such that the exit on the other side is readily identifiable. Identification of the opposite exit may be via the exit marking sign, the exit opening handle and related markings or when the field of vision provided allows visual perception of sufficient detail to recognize that there is an exit across the airplane.
This identification should be evaluated when standing at the center of the opposite exit. In certain cases, additional exit locator signs may be necessary to direct evacuees to the opposite exit. (Amendment 25-15)
(5) Paragraph (a). Exits may be “derated” in accordance with the requirements of a smaller type; that is, exits may not only be oversized, the interior may be reconfigured to specifically derate an exit that has previously been qualified as a larger type. In order to preclude the appearance of the exit being unusable, the following additional considerations have been found acceptable: (Amendment 25-15)
(i) Type A to Type I: Only seats may encroach into the projected exit opening, no more than 12-inch cumulative. A 24-inch passageway should be provided, and seats may not breakover into this passageway or into the assist space. The operating handle should be visible from the aisle. (Amendment 25-15)
(ii) Type A to Type III: A 24-inch passageway should be provided, and seats may not breakover into this passageway. The operating handle should be visible from the aisle.
(Amendment 25-15)
(iii) Type I to Type III: A 13-inch passageway is required when the passageway is bordered by seats, or by a seat and a wall. A 20-inch passageway should be provided when the passageway is bordered by walls and should be within the projected opening of the exit. The required Type III opening should be unobstructed inboard for the width of one passenger seat place. The operating handle should be visible from the aisle. (Amendment 25-15)
(6) Paragraph (c). Although these rules do not prescribe longitudinal distance between exits, they do specify passenger seating configurations matched to exit pairs in which factors of uniform exit distribution, accessibility and location to enhance effective egress must be considered. The uniform exit distribution should consider the situation where the exits on one side of the fuselage are unusable due to fire or other factors. Refer to AC 25.807-1, “Uniform Distribution of Exits,” dated 8/13/90 for additional guidance on this subject. (Amendment 25-15)
(7) Paragraph (c)(6). Seats that have dual approval for occupancy by either crew/observers and passengers will be included in the passenger seating configuration for determining the required number of exits. Regarding removal of excess exits, regardless of airplane certification basis, the following criteria applies: (Amendment 25-15)
(i) All interior and exterior exit signs, markings, and lighting pertaining to the deactivated exits must be removed. There must be no recognizable evidence of the deactivated exits, visible to occupants of the cabin. However, the exterior door outline and handle need not be obscured. (Amendment 25-15)
(ii) The modification which deactivates and obscures the exits must be approved through issuance of an amendment to the Type Certificate (TC) or Supplemental Type Certificate (STC) by the Manager, Aircraft Certification Office having jurisdiction over the project, and the airplane cabin, as modified, must remain in compliance with the certification basis of the model. (Amendment 25-15)
(iii) Also refer to AC 20-60, “Accessibility to Excess Emergency Exits,” dated 7/18/68. (Amendment 25-15)
(8) Paragraph (c). An airplane with a Type I sized exit located in the forward left-hand side of the fuselage, a pair of Type III exits in the middle, and a Type I sized exit located in the aft right-hand side of the fuselage should be limited to a maximum passenger seating capacity of 70, because of concerns with oversized dead-end zones if either the left- or right-side exits are unusable. (Amendment 25-0)
(9) Paragraph (c). An airplane with a pair of exits forward in the fuselage with the left one Type I sized and the right one Type III sized, and a pair of exits in the aft end of the fuselage with the left one Type III sized and the right one Type I sized may be approved for passenger seating capacities up to 79. If an emergency evacuation demonstration is required, then either the left-side or right-side exits should be selected so as not to unduly penalize this well-balanced arrangement or to make a radical departure from all previous demonstrations. Refer to figure 324-1. (Amendment 25-0)
(10) Paragraphs (c) and (d). When establishing the maximum capacity to be listed on the type data sheet, consideration should be given to all relevant parameters. For example, if the exit-limited passenger capacity as defined in § 25.807(c) has not been substantiated by compliance with the evacuation demonstration requirements of § 25.803, the data sheet should reflect the evacuation limit and not the exit limit. Other limiting factors include, but are not limited to, structural capability, seating density (uniform distribution of exits), or ditching exits.
The maximum passenger capacity is also limited by the ditching requirements of § 25.807(d) whether certification for ditching is requested or not. In any case, the data sheet should not list a capacity for which the airplane is not capable. When the type data sheet limit is not the § 25.807(c) exit limit, an additional note, which briefly describes the reason for the limit, is appropriate. (Amendment 25-0)
(11) Paragraph (d). All transport category airplanes must have ditching exits whether or not ditching certification was requested. Actually, this guidance has been in effect since April 9, 1957, as reflected in Amendment 4b-5, "Emergency Evacuation Provisions," to CAR 4b.
(Amendment 25-0)
(12) Paragraph (c) and (d). Flight attendants are considered part of the crew and are not included in the passenger seating capacity mentioned in § 25.807(c) and (d). (Amendment 25-0)
(13) Paragraph (c) and (d). An airplane design is determined to be eligible for a certain passenger seating complement which is commensurate with meeting all of the relevant portions of § 25.807. That is, in addition to meeting table of § 25.807(c)(1), the eligibility complement is also governed by the ditching requirements of § 25.807(d), whether certification for ditching is requested or not. (Amendment 25-0)
(14) Paragraph (d)(2). The wording “a passenger seating configuration, excluding pilot seats, of 10 seats or more,” which was promulgated with the intent of being consistent with Amendment 23-10 to part 23, does not directly address seats intended for use by observers or flight attendants. Seats approved for use by observers or flight attendants are not included in the passenger seating configuration. Seats that have dual approval for occupancy by either
236 crew/observers or passengers will be included in the passenger seating configuration for determining the required number of exits. (Amendment 25-32)
(15) Paragraph (d)(3). The wording “a passenger seating configuration, excluding pilot seats, of 35 seats or less,” which was promulgated with the intent of being consistent with Amendment 23-10 to part 23, does not directly address seats intended for use by observers or flight attendants. Seats approved for use by observers or flight attendants are not included in the passenger seating configuration. Seats that have dual approval for occupancy by either crew/observers or passengers will be included in the passenger seating configuration for determining the required number of exits. (Amendment 25-32)
325. AMENDMENT 25-46, Effective February 11, 1978.
a. Regulation.
(a) Type and location. For the purpose of this Part, the types and locations of exits are as follows:
(1) Type I. This type must have a rectangular opening of not less than 24 inches wide by 48 inches high, with corner radii not greater than one-third the width of the exit. Type I exits must be floor level exits.
(2) Type II. This type must have a rectangular opening of not less than 20 inches wide by 44 inches high, with corner radii not greater than one-third the width of the exit. Type II exits must be floor level exits unless located over the wing, in which case they may not have a step-up inside the airplane of more than 10 inches nor a stepdown outside the airplane of more than 17 inches.
(3) Type III. This type must have a rectangular opening of not less than 20 inches wide by 36 inches high, with corner radii not greater than one-third the width of the exit, and with a step-up inside the airplane of not more than 20 inches. If the exit is located over-the-wing the step-down outside the airplane may not exceed 27 inches.
(4) Type IV. This type must have a rectangular opening of not less than 19 inches wide by 26 inches high, with corner radii not greater than one-third the width of the exit, located over the wing, with a step-up inside the airplane of not more than 29 inches and a stepdown outside the airplane of not more than 36 inches.
(5) Ventral. This type is an exit from the passenger compartment through the pressure shell and the bottom fuselage skin. The dimensions and physical configuration of this type of exit must allow at least the same rate of egress as a Type I with the airplane in the normal ground attitude, with landing gear extended.
(6) Tail cone. This type is an aft exit from the passenger compartment through the pressure shell and through an openable cone of the fuselage aft of the pressure shell.