Federal Register / Vol. 61, No. 218 / Friday, November 8, 1996 / Rules and Regulations
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57946 Federal Register / Vol. 61, No. 218 / Friday, November 8, 1996 / Rules and Regulations DEPARTMENT OF TRANSPORTATION substantive bearing on those proposed exits, are based on the assumption that in Notice 90±4; however, they also affect only half of the exits will be usable Federal Aviation Administration the editorial structure of those sections. during an actual emergency due to fire, Where pertinent, the effect of those structural damage or other adverse 14 CFR Part 25 amendments on the changes proposed circumstance. [Docket No. 26140; Amendment No. 25±88] in Notice 90±4 is discussed below. None Section 25.807(d) currently specifies of the other amendments adopted the type and number of emergency exits RIN 2120±AC43 during this period have any bearing on required for three ranges of passenger seating capacities. The first range, Type and Number of Passenger the proposals of Notice No. 90±4. passenger seating configurations of one Emergency Exits Required in Current Requirements of Part 25 to 179, is addressed in § 25.807(d)(1) in Transport Category Airplanes Part 25 currently defines seven types a table that outlines the specific type AGENCY: Federal Aviation of passenger emergency exits for and number of exits that must be Administration, DOT. transport category airplanesÐType A, provided. Those standards have been in ACTION: Final rule. Types I through IV, tail cone and effect for several decades and were ventral. As defined in § 25.807, exits in based more on industry practice during SUMMARY: This amendment defines two fuselage sides range in size from large the reciprocating-engine transport new types of passenger emergency exits Type A exits, which must be a airplane era than on any particular in transport category airplanes, provides minimum of 42 inches wide by 72 testing. more consistent standards with respect inches high, to Type IV exits, which For the second range, passenger to the passenger seating allowed for must be a minimum of 19 inches wide seating configurations of 180 to 299, each exit type and combination of exit by 26 inches high. Although an exit may § 25.807(d)(1) uses a different approach. types, and requires escape slides to be exceed the minimum dimensions Instead of specifying the type and erected in less time. These changes specified for a particular type, it is number of exits required for those allow more flexibility in the design of considered to be of that type unless it airplanes, a second table supplements emergency exits and reflect recent qualifies in all respects as one of the the first by specifying the number of improvements in escape slide larger exit types. Typically, the larger passenger seats, in addition to 179, that technology. They will enable more cost- exits are hinged or translating doors may be installed for various types of effective emergency exit arrangements while the smaller exits are typically additional exits. For example, the first and, in the case of escape slides, enable removable hatches. table specifies that an airplane with 179 more rapid egress of passengers under Section 25.809(b)(2) requires that each passenger seats must have two pairs of emergency conditions. emergency exit must be capable of being Type I exits and two pairs of Type III opened, when there is no fuselage EFFECTIVE DATE: December 9, 1996. exits. The second table specifies that the deformation, within 10 seconds seating may be increased by 45 FOR FURTHER INFORMATION CONTACT: Gary measured from the time when the passengers for each additional pair of L. Killion, Manager, Regulations Branch opening means is actuated to the time Type I exits installed. An airplane with (ANM±114), Transport Standards Staff, when the exit if fully opened. three pairs of Type I exits and two pairs Transport Airplane Directorate, Aircraft It must be emphasized that, except for of Type III exits would, therefore, be Certification Service, FAA, 1601 Lind tail-cone or ventral exits, all references permitted, insofar as the type and Ave. SW., Renton, WA 98055±4056; to the types and numbers of required number of exits is concerned, to have a telephone (206) 227±2194. passenger emergency exits in part 25 passenger seating configuration of 224. SUPPLEMENTARY INFORMATION: and this final rule refer to the exits For the third range, passenger seating required in each side of the fuselage, not configurations greater than 299, Background the total for the airplane. Although they § 25.807(d)(2) simply states that each This amendment is based on Notice of are not required to be symmetrical, exit installed in the side of the fuselage Proposed Rulemaking (NPRM) No. 90± corresponding exits on opposite sides of must be either a Type I or Type A exit 4 which was published in the Federal the fuselage are usually referred to as and that seating configurations of 45 Register on February 22, 1990 (55 FR ``exit pairs'' to preclude confusion and 110 are allowed for each pair of 6344). In that notice, the FAA proposed between the total number of exits and Type I exits and each pair of Type A amendments to 14 CFR part 25 that the number of exits on each side. The exits, respectively. would revise the current requirements number of additional passenger seats Section 25.807(d)(3) specifies the for the passenger emergency exits of that may be installed for each additional number of additional passenger seats transport category airplanes and define exit pair of a specific type is sometimes that may be provided when creditable two new exit types. In addition, the referred to as the ``exit rating'' for that ventral or tail-cone exits are installed. In FAA also proposed to require escape type. When an ``exit pair'' consists of order to receive any credit as a slides to be erected in less time, a two different types of exits, the exits are passenger emergency exit, a ventral or reflection of improvements in escape both considered to be of the type with tail-cone exit must provide the same slide state-of-the-art. the smaller exit rating. Generally, no rate of egress as a Type III exit with the Since the time Notice No. 90±4 was credit is given for an exit on one side airplane in the most adverse exit published, a number of amendments with no corresponding exit on the other opening condition that would result were adopted. The changes adopted side. (Even though no credit is given to from the collapse of one or more landing with Amendment 25±72 (55 FR 29781, such exits, they are required to meet all gear legs. July 20, 1990) are largely nonsubstantive applicable exit design requirements As amended recently by Amendment in nature; however, the editorial because they may be used by occupants 25±72, § 25.807(d)(5) provides flexibility structure of the sections involved in the under emergency conditions.) in the type and number of exits required proposals of Notice No. 90±4 was Note that the standards of part 25, by stating that an alternate emergency changed considerably. The changes including those for emergency exit configuration may be approved in adopted with Amendment 25±76 (57 FR evacuation demonstrations as well as lieu of that specified in either 19220, May 4, 1992) do not have any those concerning types and numbers of § 25.807(d) (1) or (2) provided the Federal Register / Vol. 61, No. 218 / Friday, November 8, 1996 / Rules and Regulations 57947 overall evacuation capability is shown the ground must also be capable of additional pair of Type I exits. Thus the to be equal to or greater than that of the carrying two parallel lines of evacuees increase in the number of passenger specified emergency exit configuration. simultaneously. seats allowed, if one additional pair of This means, for example, that one pair Section 25.813(b) requires adequate Type I exits were installed, varies from of larger exits could be substituted in space next to one side of each 45 to 70, depending on the initial some cases for two pairs of smaller emergency exit, other than a Type A airplane exit configuration and the total exits. exit, that is required by § 25.810(a) to passenger seating capacity. Providing the type and number of have an assist means to allow The additional passenger seating exits specified for a given number of crewmembers to assist in the capacity gained by adding a pair of Type passenger seats does not, in itself, evacuation. Because there are two III exits varies in a similar manner. The ensure that an airplane can be approved parallel lines of evacuees to assist, each first table of § 25.807(d)(1) currently with that many seats. Other Type A emergency exit is required to allows 79 passenger seats if one pair of requirements, such as uniform have an assist space on each side of the Type I and one pair of Type III exits are distribution of passenger seats and exits exit. Unlike other exit types, Type A installed. If one more pair of Type III and the demonstrated emergency exits must have such assist space exits were installed, the allowable evacuation capability, may actually regardless of whether the exit is number of passenger seats would be limit seating to fewer passengers. required to have an assist means. At the increased by 30 to a total of 109 Part 25 specifies that a means must be time Notice 90±4 was issued, the latter passenger seats. In contrast, two pair of provided to assist passengers in requirement was contained in Type I exits and one pair of Type III descending to the ground for each exit, § 25.807(a)(7)(vii); however, it has since exits are currently required for a other than an overwing exit, that is more been consolidated with the former in maximum seating capacity of 139.