(3) The means to open normally used external doors is required to be simple (such as a rotating handle) and to be accessible from the inside or the outside. To prevent the inadvertent use of emergency exits (separate from normal entry doors) for routine entry and exit with the resulting "wear and tear," the normally used doors for entry and exits should be equipped with operating handles and instructions distinctly different from those of the emergency exits.
Obviously, the above does not apply to normally used exits which are also the primary (or only) emergency exits.
(4) Reasonable provisions to prevent jamming of external doors include the following:
(1) Design features of doors which are insensitive to large fuselage deflections for door operation.
(i1) Provision of clearance between door and door frame latching devices sufficient to allow some relative deflection between the door and door frame and still allow door operation. The relative deflections may be determined by static test or by an analyais approved by the FAA.
Sliding doors are frequently used in transport helicopters for versatility and utility reasons. If sliding doors are used, one of the following features of design may be required to assure that the requirements of § 29.783(d) are met:
(A) The sliding door(s) must be provided with Jettison features which allow release of the door(s)from the tracks (to preclude Jamming).
The emergency release is generally separate and distinct from the normal door handle.
(B) Separate emergency exits of appropriate size and number may be installed in the sliding door(s).
(C) Separate emergency exits of appropriate gize and number may be installed in addition to the sliding door(s).
Whether or not the sliding door is qualified as an emergency exit, it must meet the remaining door design standards. mechanism of external doors may provide for visual observation of the door frame , of the looking frame and the latching components for engagement or for visual observation of "flag" areas of the locking mechanism. If "flag" areas are used (such as tabs or shoulders which protrude into the crewmember's line of sight when the latches are engaged (locked)), care should be taken to assure that the tab is permanently affixed (or an integral part) to the looking mechanism; and it should not give of the latching mechanism. "Visual means to signal" to crewmembers "when normally, erroneous readings to the crewmembers under any foreseeable operation or failure used external doors are closed and fully locked" may be provided by annunciator Chap 2 Par 334 549
AC 29-2, CHG 1 11/19/84 * panel lights or equivalent means. The visual indicating system may consist of an indicator for each individual door, or a system connecting all doors in series.
If the latter system is used, it need not necessarily show which door is not fully locked. It is not necessary that more than one crewmember be able to ascertain by a visual signal that all external doors normally used by the crew in supplying the rotorcraft, or in loading and unloading passengers and cargo, are fully closed and The visual signal should be located so that it may easily be seen by the appropriate crewmember from his station.
(6) For § 29.783(f), the auxiliary safety latching device to "prevent the door from opening when the primary latching mechanism fails" can be provided by the same multiple load path features which neet the § 29.783(c) requirement for prevention of door opening in flight after a "mechanical failure." If a completely separate "auxiliary safety latching device" is used, it should allow the door to be opened from the inside, or outside, when in place. If the device must be removed to allow use of the door, "suitable operating procedures" (1.e., placards and RFM instructions) will be required for removal of the device during
(7) Additional standards for "airstair doors" were added by Amendment 29-20.
An analysis or test may be used to prove compliance with deformation standards in § 29.783(g) (1).
A sketch, drawing, or demonstration may be used to prove the door is useable for the conditions described in § 29.783(g) (2).
335. § 29.785 (through Amendment 29-19) SEATS, SAFETY BELTS, AND HARNESSES.
a • Explanation
(1) This section requires that seats, belts, harnesses, and adjacent parts of the rotorcraft be substantiated for the structural loads resulting from the inertia forces of § 29.56l as well as normal flight and ground inertia forces on a 170-pound occupant. The inertia forces of § 29.561 are ultimate loads and must be multiplied by a factor of 1.33 in determining the "strength of attachment" of each seat to structure and each belt or harness to structure. The seat, belt, etc., are required to sustain applied loads and to protect the occupant from serious injury. The pilot seats must also sustain the effects of the pilot forces of $ 29.397.
(2) In addition, the "occupant must be protected from head injury" by the seat belt and one of the following:
(1) A harness to prevent the head from contacting an injurious • object.
Chap 2 550 Par 334
* (11) Elimination of injurious object within striking distance of the head.
(i11) A cushioned rest as specified.
(3) Handholds are required to steady occupants using the aisle in moderately rough air.
(4) Projecting objects which would injure occupants in normal flight must be padded.
Procedures•
(1) Each seat with its belts and harnesses are to be substantiated for the flight, ground, and emergency landing loads of § 29.561 by structural test or stress analysis. Section 29.785(b) states that "each seat must be approved." FAA approval can be gained by Technical Standard Order (TSO) approval or by accomplishing sufficient structural substantiation to gain FAA approval of the seat and its belt (9) as part of the Type Design of the rotorcraft. ISO No. C-39 concerns standards for aircraft seats, including rotorcraft seats. If TSO No. C-39 is used as an approval basis for a specific rotorcraft seat, the seat should be checked to assure it has been substantiated for the vertical (up and down) and side loads imposed by installation in the aircraft. For example, TSO No. C-39 (and NAS 809) specifies an ultimate down load of 4.0g which is in agreement with the 4.0g emergency landing load factor of $ 29.561, but it may be less than the design maneuver load factor (which can be as high as 3.5g limit or
5.25g ultimate).
(1) The 1.33 factor is specified for substantiation of attachments of each seat to the structure and each safety belt or harness to the seat or structure for § 29.561 loads, whether analysis or test 1s used.
If static testing of seats, belts, and harnesses is used, the body block of NAS 809 may be used. The corners of the NAS 809 body block may be radiused and padded if it is found that the small radii cause premature, unrealistic crippling of thin wall tubing or other structure used in the seat.
The substantiation of the pilot seats is required to include pilot forces of § 29.397 in conjunction with normal flight and ground loads. For example, the pilot foot force (195 pounds ultimate) must be reacted by the seat.
(2) The following oriteria have been found satiafactory for preventing occupant head injuries:
Chap 2 Par 335 551
AC 29-2, CHG 1 11/19/84
(1) If a harness is used, it should support the shoulders without * applying hazardous loads to the side or front of the neck. It should be easily donned and a single point release with the seat belt is preferred. If separate release is provided, it must be simple, compatible with the seat belt release, and near the seat belt release. The harness should be tested in conjunction with the seat belt using a "body block" similar to that of NAS 809 if possible. If the harness is tested separately from the belt, it should be tested to 50 percent of the forward crash loads for the entire occupant weight of 170 pounds, unless that percentage distribution is found to be unrealistic by a rational analysis.
head and other vital parts can be accomplished by removal of objects with sharp edges or rigid surfaces from within striking distance of vital parts of the occupant. Dimensions and weights for typical occupants are available in U.S. Army USAAULABS Reports 70-22 (August 1969) and 66-39 (June 1966) and NACA Report IN 2991 (August 1953). Because of the range of occupant head striking distance, a combination of "elimination of injurious objects" and "cushioned rests" may be (i1i) An acceptable cushioned rest can be provided by use of a l-inch thickness of foamed polyvinyl chloride (PVC), or equivalent energy absorbing material. The density of material should be in the 5 to 10 pounds per cubic foot density range. PVC foam has the property of absorbing energy efficiently with negligible rebond effects. PVC foam recovers slowly to the original configuration after deformation. If PVC foam is used, however, care must be taken in its application relative to its flammability characteristics (ref. § 29.853).
(3) Handholds for the occupants are generally provided by seat backs adjacent to the aisle. If the seat backs fold, the amount of support provided by the seat backs before they fold must be evaluated in a furnished interior or mock up. To provide adequate support, the seat back may use an easily disengaged latch or adequate friction in the hinge mechanism to obtain adequate support. Handholds along the aisle are, of course, not needed for rotorcraft with no aisles or where seat belts must be fastened during flight.
(4) Projecting objects which could injure occupants in normal flight should be padded. The amount of padding required depends on the location, size, and minimum radius of the projecting object. In general, this requirement will mean that sharp edges must be padded with one-half inch of PVC foam or equivalent (5 to 10 1bs. density), while objects with radil in excess of 1 inch may neet the requirements of § 29.785(e) with a lesser amount of energy absorbing padding, 1f it can be contacted only by persons "moving about in the rotorcraft in normal flight."
Chap 2 552 Par 335
* 336. § 29.787 (through Amendment 29-19) CARGO AND BAGGAGE COMPARTMENTS.
a • Explanation.
(1) This section requires that cargo and baggage compartments be designed for normal flight and ground loads and for a 4g ultimate forward load condition. Maximum placarded weights and oritical distributions are to be considered.
(2) Means to prevent cargo shifting and contact between any cargo lamp bulb and cargo is to be provided.
b. Procedures. Structure tests or analyses may be used for substantiation for the design loads.
(1) Nets or straps may be used to prevent cargo shifting. The nets or straps are required to be substantiated for the structural loads. They need a means for adjustment to aasure proper restraint for different sizes and shapes of cargo.
inside corners to prevent contact with cargo. (2) Cargo lamp bulbs need to be guarded, receased, or placed in upper •
337. § 29.801 DITCHING. (RESERVED).
Chap 2 Par 336 553 (thru 567)
AC 29-2, CHG 1 11/19/84 * 338. § 29.803 (through Amendment 29-19) EMERGENCY EVACUATION, Explanation. This regulation specifies that "meana for rapid evacuation in a crash landing" be provided considering the landing gear extended or retracted, and "considering the possibility of fire." Any external exits, whether normal entrance doors or service doors, can be considered as emergency exits if the requirements of $§ 29.805 through 29.815 are met. "Limited amphibian rotorcraft emergency exits are required to be designed for probable maximum local water pressure (or shown to have nonhazardous failure characteristics) and to have a specified number of exits above the water level.
Limited amphibian rotorcraft are approved under the provisions of §§ 29.519 and
29.755(b). Sections 29.801 and 29.807(d) refer to similar standards that pertain to "rotorcraft ditching configurations."
b. Procedures. Exits, arrangement, markings, access, and aisle widths as specified in § 29.805 through 29.815 are to be provided. Recent rotorcraft designs have been approved under the "ditching" standards of § 29.801. Previous "limited amphibian rotorcraft" were designed to the same standards.
339. § 29.805 (through Amendment 29-19) FLIGHTCREW EMERGENCY EXITS.
Explanation. Flightorew emergency exits are required when passenger exits are not convenient. The placement of litters, cargo, or bulkheads may prevent passenger exits from being convenient to the flightcrew. Flightcrew exits, if required, are to be of sufficient size and located on both sides of the rotorcraft (or one top hatch) to "allow rapid evacuation of the flightcrew." A test or tests are required.
b. Procedures. Flightcrew emergency exits, if required, may consist of one overhead hatch or two side exits (one on either side). The size is not explicitly defined except that it be of sufficient size. • . to allow rapid evacuation of the flightcrew." The ability for "rapid evacuation" should be demonstrated by test. For side exits located immediately adjacent to the crew seat and exceeding Type IV exits ($ 29.807) in size, the test demonstration can be accomplished by normal use and evaluation of the exits by the FAA crew during Type Inspection Authorization (TIA) testing. For any overhead exit or side of fuselage exits not meeting Type IV dimensions, a special demonstration test should be accomplished. This demonstration should show that 2.5 percentile to
97.5 percentile men could egress rapidly through the crew exit(s), i.e., men 5 feet 5 inches to 6 feet 2 inches in height and up to 210 pounds in weight. • Chap 2 568 Par 338
* 340. § 29.807 (through Amendment 29-19) PASSENGER EMERGENCY EXITS.
a. Explanation. The normal passenger exits (type and number in each side of fuselage) are specified as follows:
(1) For overland operations.
Passenger Emergency exits (rectangular with corner radii of width/3) Seating for each side of the fuselage Capacity Floor level Step-up -29" Max.
Type II Type III туре IV 24" x 48" 20" Х 44" 20" Х 36" 19" × 26" 1 through 10 1 11 through 19 1 or 2 20 through 39 1 40 through 59 1 60 through 79 1 1 or 2
(2) For overwater operations (related to ditching an optional standard).
Passenger Emergency exits (rectangular with corner radii of width/3) Seating for each side of the fuselage Capacity Threshold Above Waterline Type III Type IV 20" × 36" 19" X 26" w/step up - 29" 1 through 9 1 10 through 35 1* Each Additional Unit of 35 1* The passenger seat-to-exit ratio may be inoreased by using larger exits if proven by analyses or tests.
(3) For crash rollover conditions. Sufficient top, bottom, or ends of fuselage exits are to be provided for evacuation unless the probability of the rotorcraft coming to rest on ita side in a crash landing is extremely remote.
(4) Ramp exits to replace Type I or II exits are permitted.
(5) Each emergency exit must be functionally tested.
b. Procedures.
(1) The number and size of overland and overwater operation exits will be as specified. The use of oversize exits is allowed if the threshold is flat and of the specified width. * Chap 2 Par 340 569
AC 29-2, CHG 1 11/19/84 * (2) The top, bottom, or end fuselage exits should be provided unless features of design are provided which prevent the rotorcraft from coming to rest on its side in a crash landing, and unless suffioient fail-safe and fatigue tests and analyses are conducted of the landing gear and support structure to show it is unlikely that the rotorcraft will come to rest on its side as a result of a single structural failure. An analysis is generally necessary to prove compliance with $ 29.807 (c).
(3) Ramp exits may be used in place of one Type 1 or one Type 11 exit if the required Type I or Type II exit is impractical, and if the § 29.813 exit access requirements are met by the ramp exits.
(4) Eaoh emergency exit is to be opened from the inside and the outside as a functional test. Interior panels and seats should be installed for the exit functional tests to check for interferences and other effects. Section 29.813 pertains to access to the exits.
341. 29.809 (through Amendment 29-19) EMERGENCY EXIT ARRANGEMENT.
a • Explanation. Emergency exits are to be provided which result in an unobstructed opening to the outside. The following emergency exit requirements are the same as passenger door requirements of § 29.783 and noted for convenience.
(1) Openable from inside or outside.
(2) Simple and obvious means for opening.
(3) Means for locking.
(4) Means to prevent opening in flight inadvertently or as a result of mechanical failure.
(5) Means to minimize. Jamming in a minor crash landing.
NOTE: In addition the following emergency exit requirements are: (1) the means of opening may not require exceptional effort; and (2) a slide (for floor level exits) or rope must be provided as prescribed for exits whose thresholds are more than 6 feet from the ground (unless located over the wing). Sections 29.1411(c) and 29.1561 contain other standards for the descent devices.
b. Procedures. Subparagraphs 1 through 5 of the above explanation are covered in the procedure, for § 29.783, paragraph 334 of this document.
Chap 2 570 Par 340
tests of § 29,807 (f) are conducted. If the effort required to open the exit is in the range of 40 to 50 pounds, it is recommended that a person of slight stature, such as a female in the 90 to 110 pound weight range, be used for the exit opening demonstration/test. In any case, the average load required to operate the exit release mechanism and open the exit should not exceed 50 pounds, and the maximum individual load of a test series should not exceed 55 pounds.
(2) If an approved escape slide, or its equivalent, is provided for exits more than 6 feet from the ground with the landing gear extended, it should be located near the door and conspicuously marked, Automatic inflation and deployment under emergency conditions are the preferred means of operation but are not required by § 29.809. If automatic inflation and deployment features are provided, design features should prevent inadvertent deployment if the exit is a door used for normal entry and/or service. If manual deployment methods are used, they must be simple and easily carried out by a person of slight built and strength. The slide should rapidly inflate upon deployment. See § 29.809(f) for standards concerning an escape rope.
342. § 29.811 (through Amendment 29-19) EMERGENCY EXIT MARKING.
a. Explanation. This regulation covers both the marking and illumination by emergenoy lighting.
(1) Locating and marking signs are speoified for each emergenoy exit with the following features:
(1) Locating signs and marking signs are to-- (A) Be recognizable from a distance equal to the width of the cabin;
(B) Have 1-inch white letters on a 2-inoh red background (colors may be reversed); and (C) Be self- or eleotrically illuminated to a minimum brightness of 160 microlamberts.
(11) Locating signs visible to occupants approaching along the main aisle are required for each exit.
(A) The sign is required next to or above the aisle for floor level exits.
(B) Bulkheads or dividers obscuring exits must have exit locating signs except as stated.
(2) Exit operating or release handle instructions are to be-- Chap 2 Par 341 571
AC 29-2, CHG 1 11/19/84 * (1) Readable from a distance of 30 inches; and
(11) Supplemented with a red arrow and sign (for Type I or Type II exits with a handle having rotary motion) with the following features provided:
(A) A red arrow with three-fourths inch shaft, a head of twice the shaft width, and 70° arc at 75 percent of handle length.
(B) The word "open" in red letters 1 inch high near the head of the arrow.
(3) Independent source of light, as prescribed, 1s to be installed to--
(1) Illuminate marking and locating signs;
(11) Provide general lighting of 0.05 foot-candles at 40-inch intervals at armrest height along the main aisle; and
(111) Operate manually and automatically in a crash landing and when the normal electrical power is interrupted.
(4) External exit markings are required which include a 2 inch wide band around the exit, identification, and instructions for opening. The external markings are to have a reflectance difference of 30 percent from the fuselage surface finish.
(5) Emergency exits signs may read simply "EXIT,"
(6) Excess exits should meet all of the "EXIT" standards or should not be identified as an exit.
b. Procedures.
(l) Emergency exit looating signs may be located to the side of the aisle for small fuselage heights, rather than over the aisle where it may present a hazard to the occupant's head and possibly impede egress. for small passenger cabins one self-illuminated sign stating "EXIT" may be used as both the locating and marking sign for an individual exit on one side of the cabin (operating instructions will, of course, still be required). If one "EXIT" sign is used to both looate and mark the exit, it should be attached to the fuselage above the exit and not to the exit itself. If it is attached to the exit itself and the exit is discarded from the cabin after opening, the locating function of the exit sign is lost when the exit is removed. That is, there is no sign to locate the exit for passengers other than for the one who discarded the exit. The exit locating sign is a necessity to direct all occupants.
(2) Operating instructions should be provided as specified. They should be kept short but clear; e.g., "rotate handle," "push," "pull," etc.
Chap 2 572 Par 342
* (3) Lighting should be provided as specified to illuminate the cabin for egress paths and to supplement lighting of the exit operating instructions signs.
(4) The reflectance of external exit markings can be checked by appropriate electro-optical instrumentation or by use of photometer card sets.
Advisory Circular No. 20-47 provides information for complying with identical standards contained in § 25.811. These are also acceptable for § 29.811. The Munsell Color Company, 2441 North Calvert Street, Baltimore, Maryland 21218, provides a set of cards which includes shades of most commonly used colors.
343. § 29.813 (through Amendment 29-19) EMERGENCY EXIT ACCESS.
a. Explanation. Paragraph (a) of § 29.813 prescribes design details for passageways, both between passenger compartments and for access to Type I and II emergency exits, should they be provided. such passageways are not made mandatory by § 29.813 although most larger rotororaft have used them. Some utility or "wide-body" rotorcraft may have open areas between the crew area (pilots) and passenger area (cabin). These configurations may have lateral seating arrangements providing access to emergency exits of Type I or Il size, even though they may not be required by § 29.807 (b). These designs may not have a main aisle.
(1) Paragraph (c) of this standard concerns access to Type III and Type IV exits. Although "passageways" with explicit requirements are not required for Type III and Type IV exita, "access from each aisle to each Type III and Type IV exit" is required.
(2) For exits whose thresholds are more than 6 feet above the ground, additional space adjacent to the exit is required to allow room for a crewmember to assist passengers with the descent device such as an escape slide or rope noted in § 29.809(f).
(3) In addition to requiring passageways and crewmember space adjacent to exits over 6 feet above the ground, this standard does not allow obstructions in the projected opening of Type III or Type IV emergency exits for one seat width from the exit, except as noted. For passenger seating configurations of 19 or less, minor obstructions into the projection of the exit are allowed only if "compensating factors to maintain the effectiveness of the exit" are provided.
b. Procedures.
(1) The provision for unobstructed passageways, at least 20 inches wide as specified, is straightforward for medium or large cabins with a main aisle and a typical rectangular floor plan. Care should be taken to assure that seats (with lateral or fore-and-aft movement) or galleys (with doors or drawers) are not installed so that they can encroach upon the required passageway. Design features such as stops in seat tracks, seat back mechanisms, stops in galley door (or drawer) mechanisms may be required to assure that unobstructed passageways are provided.
Chap 2 Par 342 573
AC 29-2, CHG 1 11/19/84
(2) The requirement (added by Amendment 29-12) that access from each aisle to each Type III and Type IV exit" be provided may add design features to the interior of many typical compact interiors of medium-size rotorcraft.
Rotorcraft with emergency exits located in either hinged or sliding doors and having passenger area encroachment or protusions by compartments for fuel cells, gear boxes, etc., may require special design features to assure that passengers seated to one side or one area of the cabin have "access" to all Type III or Type IV exits on the same or other side of the rotorcraft. The cabin must not be separated into compartments or partitioned. For example, fold down seat back mechanisms may be required for compact cabin configurations having only lateral aisles rather than longitudinal aisles and having Type Ill or Type IV exits looated on each side of the cabin at the end of the lateral seat row or rows.
(3) The space adjacent to an exit that requires a crewmember to assist passengers with descent devices must be large enough to prevent the crewmember from becoming an obstruction in access to the exit. Twenty inches of access must be maintained.
(4) Minor obstructions are allowed in the projected opening of Type III or Type IV exits (for 19 or less passenger seat configurations) if &compensating factors to maintain the effectiveness of the exit" are provided. Compensating factors may include such design features as larger than required exit opening, additional exits beyond the minimum number required, or steps or other assist features which facilitate egress through the exit with the obstruction. lest or analysis may be required to prove the effectiveness of the compensating feature.
344. § 29.815 (through Amendment 29-19) MAIN AISLE WIDTH.
a • Explanation. Main aisle widths are specified in the following table:
Minimum main passenger aisle width Passenger seating capacity Less than 25 inches 25 inches and more from floor from floor Inches Inches 10 or less---. 12# 15 11 through 19-- 12 20 20 or more--=- 15 20 *A narrow width not less than 9 inches may be approved when substantiated by tests found necessary by the Administrator.
Chap 2 574 Par 343