(2) The type inspection authorization may be used to perform compliance evaluation utilizing a full-scale rotorcraft in calm water. Designs may be accepted “by compliance inspection” if location of exit and flotation devices relative to each other ensures that interference is impossible. In this case, a demonstration is unnecessary.
AC 29.809. § 29.809 (Amendment 29-3) 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 AC 29.783.
(1) The effort required to open the exit can be evaluated when the 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 Page D - 101
carried out by a person of slight build and strength. The slide should rapidly inflate upon deployment. See § 29.809(f) for standards concerning an escape rope.
AC 29.809A. § 29.809 (Amendment 29-30) EMERGENCY EXIT ARRANGEMENT.
a. Explanation.
(1) Amendment 29-29 added the phrase, “under the ultimate forces in § 29.783(d),” to clarify that the following inertial load factors previously stated in § 29.809 were not altered by Amendment 29-29 and that the previous design conditions still apply to § 29.809(e) exits as well as the doors:
(i) Upward - 1.5g
(ii) Forward - 4.0g
(iii) Sideward - 2.0g
(iv) Downward - 4.0g
(2) Amendment 29-30 further revised the requirements of § 29.809 by:
(i) Amending requirements of § 29.809(f) to include landing gear malfunction or failure in determining the distance from the exit to the ground. (A means is required to assist occupants in descending to the ground when that distance is more than 6 feet);
(ii) Adding specific requirements for automatic slides, automatic slide deployment (not optional), and slide qualification in a new § 29.809(g);
(iii) Allowing relaxation in § 29.809(h) such that a rope or other assist means may be used rather than a slide for rotorcraft having 30 or fewer passenger seats provided an evacuation demonstration is successfully accomplished; and,
(iv) Moving but not changing the egress rope requirements formerly in § 29.809(f) to a new § 29.809(i).
b. Procedures.
(1) The procedures of paragraph AC 29.809 continue to apply except compliance should consider landing gear collapse, breaking, or not extending as well as slide deployment and proper inflation in 25 knot winds.
(2) Automatic deployment of slides is now a requirement, not an option.
(3) Procedures for slide qualification tests are explicitly provided in § 29.809(g)(5).
Page D - 102
AC 29.811. § 29.811 (Amendment 29-24) EMERGENCY EXIT MARKING.
a. Explanation.
(1) This regulation covers both the marking and exit interior illumination by emergency lighting prior to Amendment 29-24.
(2) With adoption of Amendment 29-24, the interior emergency lighting standards were moved to § 29.812, and exterior emergency lighting standards were added. However, the standards for emergency lighting in § 29.812 apply to transport Category A rotorcraft. Transport Category B rotorcraft shall have the “emergency” lighting required in § 29.811(d). General interior lighting standards are no longer specified in § 29.811.
(3) Locating and marking signs are specified for each emergency exit with the following features:
(i) 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-inch red background (colors may be reversed); and (C) Be self- or electrically illuminated to a minimum brightness of 160 microlamberts.
(ii) 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.
(4) Exit operating or release handle instructions are to be--
(i) Readable from a distance of 30 inches; and
(ii) 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 a ¾-inch shaft, a head of twice the shaft width, and a 70° arc at 75 percent of handle length.
(B) The word “open” in red letters 1 inch high near the head of the arrow.
Page D - 103
(5) Emergency lighting.
(i) Prior to Amendment 29-24, an independent source of light, as prescribed, shall be installed in transport Category A or B rotorcraft to:
(A) Illuminate marking and locating signs;
(B) Provide general lighting of 0.05 foot-candles at 40-inch intervals at armrest height along the main aisle; and (C) Operate manually and automatically in a crash landing and when the normal electrical power is interrupted.
(ii) Amendment 29-24 requires for transport Category B rotorcraft either self- or electrically illuminated exit marking and locating signs. General lighting standards are not specified. See § 29.812 for transport Category A standards.
(6) External exit markings are required which include a 2-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.
(7) Emergency exits signs may read simply “EXIT.”
(8) Excess exits should meet all of the “EXIT” standards or should not be identified as an exit.
b. Procedures.
(1) Emergency exit locating signs may be located to the side of the aisle for small fuselage heights, rather than over the aisle where they 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 locate 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.
(3) Lighting should be provided as specified to illuminate the cabin for egress paths and to supplement lighting of the exit operating instructions signs.
Page D - 104
(4) The reflectance of external exit markings can be checked by appropriate electro-optical instrumentation or by use of photometer card sets. AC 20- 47, Exterior Colored Band Around Exits on Transport Airplanes, 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.
AC 29.811A. § 29.811 (Amendment 29-31) EMERGENCY EXIT MARKING.
a. Explanation.
(1) Amendment 29-30 changes § 29.811(f)(1) to allow marking or outlining the handles, release devices, levers, etc., of passenger emergency exits which are “normally used doors,” rather than outline the entire door of smaller transport rotorcraft.
If an exit, other than a normally used door, such as a hatch, window, etc., is approved, that exit would be marked around the perimeter as described.
(2) Amendment 29-31 added two requirements to § 29.811(a):
(i) A clarification that emergency exit markings should be conspicuously marked for egress in darkness as well as in daylight.
(ii) A requirement for visibility of emergency exit markings when the “rotorcraft is capsized (in water) and the cabin is submerged. This standard applies to rotorcraft configurations complying with § 29.801.
b. Procedures. The procedures of paragraph AC 29.811 are still applicable plus:
(1) The release device, handle, etc., of the normally used door(s) may be separate from the normally used handle of the door (such as a release system lever for sliding door rollers). To preclude jamming a sliding door, which is also an exit, in an emergency landing impact, the door should be released from the track. An emergency release handle for releasing door rollers may be used to allow the exit door to be “pushed off” the track. For smaller rotorcraft, such a release lever should comply with the necessary operating procedures and exit markings but should use a distinct, separate 2-inch wide band around the release lever per § 29.811(f)(1). That is, a distinct “band” is necessary to comply rather than a solid block of color around the release lever. Large rotorcraft should have exits marked with a distinct 2- inch band around the exit perimeter as stated in subparagraphs § 29.811(f)(1). Refer to paragraph AC 29.811 for color contrast.
(2) The interior compliance checklist should report that emergency exit markings have been evaluated by “interior compliance inspections” conducted in darkness as well as daylight, and visibility of interior emergency exit markings should be checked under submerged cabin conditions or alternate/equivalent means for those rotorcraft configurations equipped for over-water flights that are approved under § 29.801.
Page D - 105
AC 29.812. § 29.812 (Amendment 29-24) EMERGENCY LIGHTING.
a. Explanation. Section 29.812 was added by Amendment 24. This change unified the requirements for an emergency lighting system into a single paragraph and required these systems only for Category A rotorcraft. The purpose of this change was to afford passengers flying in Transport Category A rotorcraft the same level of safety in an emergency evacuation at night as passengers flying in transport category airplanes.
b. Procedures. This paragraph is quite similar to the emergency lighting system required for Part 25 airplanes. The exception is there are no requirements in this paragraph for floor proximity emergency escape path markings. The following items should be considered in the design of emergency lighting systems:
(1) There is a requirement for two controls of the system. One of these controls is located in the cabin, where it can be operated by a flight crew member or a passenger. The other control is located in the cockpit. These switches must have an “ON,” “OFF,” and “ARMED” position. These switches should operate independently of each other, and any other systems in the rotorcraft. The emergency lights must become lighted or remain lighted if the switch is either turned on, or the switch is in the armed position and there is an interruption of the rotorcraft electrical power supply.
Inertia switches should not be used to satisfy this requirement.
(2) Sharing of light bulbs with the normal cabin lighting is acceptable provided there is sufficient isolation of the emergency lighting system from the normal cabin lighting circuits. No single failure of the shared portion should render the emergency lighting system inoperative.
(3) The luminosity tests of the emergency lighting system should be accomplished with the emergency exits open.
AC 29.813. § 29.813 (Amendment 29-12) 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 rotorcraft 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 II 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 exits, “access from each aisle to each Type III and Type IV exit” is required.
Page D - 106
(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.
(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 protrusions 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 III or Type IV exits located 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. Test or analysis may be required to prove the effectiveness of the compensating feature.
Page D - 107
AC 29.815. § 29.815 (Amendment 29-12) 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 narrower wi dth not less than 9 inches may be approved when substantiated by tests found necessary by the Administrator.
b. Procedures.
(1) Provide the specified aisle minimum width where a longitudinal main aisle is provided in the type design.
(2) Historically, certain rotorcraft with short, wide cabins were initially designed without a longitudinal main aisle for military and cargo use, but were later fitted and approved for civil passenger configuration. These craft generally have 19 or less passenger seats and have either (1) outboard facing passenger seats, (2) a limited number of lateral rows with fold down seats/seat backs, or (3) a combination of lateral and longitudinal rows with and without main aisles to facilitate entrance and egress.
Page D - 108
AC 29.831. § 29.831 VENTILATION.
a. Explanation.
(1) This rule specifies minimum ventilation requirements for each passenger and crew compartment. The minimum requirement for fresh air in the crew compartment is that amount that will allow the crew to accomplish their duties without undue discomfort or fatigue which shall be at least 10 ft3/m per crewmember. The passenger and crew compartments are also required to be free from harmful or hazardous concentrations of gases or vapors. Specifically for carbon monoxide, the concentration may not exceed 1 part in 20,000 parts of air during forward flight. Failure conditions must also be considered when applying this rule.
(2) This rule becomes more significant when engine bleed air is used for conditioning of the passenger and crew compartments’ air. Certain data are necessary in order to properly analyze the bleed air provided under normal and malfunction conditions. The airframe manufacturer can normally look to the engine manufacturer for a specification of the maximum amount of air that can be extracted and the temperature of the extracted air. The engine manufacturer also normally provides a failure analysis that identifies ways the bleed air can be contaminated and the associated oil flow rates under each failure condition. The oil manufacturers are in a position to provide information regarding breakdown of the oil under different temperature conditions and the impact of that breakdown on the quality of the air being provided to the passenger and crew compartments.
b. Procedures.
(1) The passenger and crew compartments should be initially analyzed to ensure that at least 10 ft3/m per crewmember of ventilation air is being provided. The emphasis has been placed on forward flight and, “air scoops” have been one way of showing compliance with this rule. Most installations also include blowers; however, they are normally provided primarily for defogging the windshields, and a secondary benefit is some circulation during ground or hover operation. In addition, the flight test crew should be asked to do a qualitative evaluation to ensure the amount of ventilation air actually provided meets the requirement for the crew to be able to accomplish their duties without undue discomfort or fatigue. In addition, the ventilation devices provided should not excessively increase the noise level in the cockpit. Compliance with the first requirement of § 29.831(a) can therefore be shown by an analysis showing the existence of at least 10 ft3/m per crewmember, and a report from the flight test crew indicating that the amount actually provided is satisfactory.
(2) The passenger and crew compartment should be monitored under normal operating conditions for the presence of carbon monoxide. A carbon monoxide test kit is normally used for this evaluation. Air is monitored around outlets and different combinations of windows closed/open, heat off/on, air-conditioner off/on, etc., are checked to ensure all conditions are evaluated.
Page D - 109
(3) When engine bleed air is used to condition the passenger and crew compartments’ air, it should be initially substantiated that under normal operation, the amount of air being extracted does not exceed the limit established by the engine manufacturer. To accomplish this, determine the flight condition that will give the maximum bleed air flow through the flow limiter (venturi). The flow calculations should use this maximum flow condition and should also be made using the maximum tolerance diameter of the venturi throat.
(4) The engine bleed air should also be evaluated under malfunction conditions to determine a worst-case air contamination condition. (A typical worst -case malfunction is for an oil seal to fail in the engine that allows the engine oil supply to be introduced into the airflow.) With information regarding the contaminant, flow rate calculations can be made to predict the contamination levels that will be reached in the passenger and crew compartments and also the associated time duration of passenger and crew exposure. The severity of the exposure to the contaminated air is related to the temperature of the oil when it is introduced into the airflow. For example, synthetic base oils manufactured to MIL-L-7808 or MIL-L-23699 begin to break down into toxic components when the temperature exceeds 300° C (572° F). The oil manufacturers have evaluated this problem and should be in a position to provide data regarding the amount and type of toxic components to be expected, and the effect of introducing those components into the passenger and crew compartments. Therefore, from information supplied by the engine manufacturer, the worst-case air contamination condition can be calculated, and this can be compared with results of the oil manufacturers’ tests to determine if the concentrations are harmful or hazardous.
AC 29.833. § 29.833 HEATERS.
a. Explanation. This standard provides that each combustion heater must be approved. The standard contains no provisions regarding functioning of the system, environmental considerations, or malfunctions, therefore, the provisions of §§ 29.1301 and 29.1309 should be used to evaluate those aspects of an installation. The provisions of § 29.831, ventilation, should also be considered, as well as § 29.859, concerning combustion heater fire protection.
b. Procedures.
(1) Technical Standard Order, TSO-C20, was issued June 15, 1949, and amended on April 16, 1951, and concerns Combustion Heaters. If a heater chosen for installation has been qualified to the provisions of TSO-C20, it is considered to be approved. If a unit is not qualified to TSO -C20, a qualification program for the heater itself should be established with FAA/AUTHORITY certification engineers participating in the program as early as possible. The program should be based on the provisions of the TSO.
(2) The TSO refers to the SAE Aeronautical Standard, AS 143B, which specifies certain additional devices, design features, air supply considerations, performance tests, safety controls, environmental considerations, and so forth.
Page D - 110
Consideration of all of the provisions of the aeronautical standard should result in an approved unit; however, it will not necessarily result in a satisfactory installation. For environmental considerations, it should be possible to specify an environmental spectrum more suitable to rotorcraft by referencing the latest version of Document No. RTCA/DO-160, Environmental Conditions and Test Procedures for Airborne Equipment, rather than AS 143B. Other specifications may also be satisfactory.
(3) The installation evaluation should consider functioning of the system based on the provisions of § 29.1301. Section 29.1309(a) is the regulatory basis for consideration of environmental conditions, and the expected environmental conditions resulting from the installation should be compared to those specified in the TSO. If the two are not compatible, additional environmental considerations are appropriate. The provisions of § 29.1309(b) should be used to evaluate the possible malfunctions of the installed system, and this evaluation should be documented in a fault analysis. The provisions of § 29.831 should be considered since certain standards of ventilation air quality under normal and malfunction conditions are specified. Additionally the provisions of § 29.859 should also be considered.
Page D - 111
SUBPART D - DESIGN AND CONSTRUCTION
FIRE PROTECTION AC 29.851. § 29.851 FIRE EXTINGUISHERS.
a. Explanation.
(1) The standard concerns objective performance criteria for both handheld fire extinguishers in the crew and passenger compartments and built-in fire extinguisher systems if the system is required.
(2) Section 29.853(e) and (f) dictate the quantity and general location of the handheld fire extinguishers.
(3) Section 29.855(d) contains standards for cargo/baggage compartments.
(4) Sections 29.1541 and 29.1561 concern durable and conspicuous markings and placards for location and operation or use of the equipment.
(5) The rotorcraft flight manual should contain appropriate information as well.
(6) Advisory Circular 20-42C, Handheld Fire Extinguishers for use in Aircraft, provides an acceptable means of compliance with the standard.
b. Procedures.
(1) Advisory Circular 20-42C provides valuable information to select the type and size of the handheld extinguishers.
(2) The type design data shall contain appropriate information. One location should be used (recommended) for the crew compartment. Several locations may be selected to allow for evaluation and approval of several extinguishers and their locations in the passenger compartment.
(3) During a compliance inspection of a complete interior, the installation of required and optional extinguishers shall be checked for compliance.
(4) Whenever an extinguisher is installed, even though not required by § 29.853(f), it shall also comply with the standards.
Page D - 112