AC 27-1B, Chg 4 3/31/2014 AC 27.1549. § 27.1549 (Amendment 27-16) POWERPLANT MARKINGS.
See section 27.1543 of this AC.
AC 27.1549A. § 27.1549 (Amendment 27-23) POWERPLANT INSTRUMENTS.
a. Explanation. Amendment 27-23 adds the requirement of marking each OEI limit and operating range. The limits should be clearly differentiated from other limits and ranges marked on the instrument. Refer to AC 20-88A, Instrument Markings.
b. Procedures. The method of compliance is unchanged.
AC 27.1549B. § 27.1549 (Amendment 27-29) POWERPLANT INSTRUMENTS.
a. Explanation. Amendment 27-29 introduces the optional ratings of 30-second/2-minute OEI. Paragraph 27.1549(e) has been revised to show that the limits for the 30-second OEl rating are not required to be marked. Use of the 30-second OEI rating is limited to critical phases of operation after a failure or precautionary shutdown of an engine. During this critical stage of operation the crew should not be required to monitor engine instruments to avoid exceedances. Automatic control of the 30-second OEI limits are required by § 27.1143(e) and therefore the 30-second OEI limits are not required to be marked.
b. Procedures. The method of compliance is unchanged except the marking of 30-second OEI limits are unnecessary.
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AC 27.1549C.§ 27.1549 (AMENDMENT 27-51) POWERPLANT INSTRUMENTS.
a. Explanation. Amendment 27-51 changed the requirements for displaying the normal operating range of powerplant instruments. Most modern glass cockpit designs utilize the "dark, quiet cockpit" concept, which means that yellow or red is presented to indicate abnormal conditions; green ranges are not presented. This approach has required a finding of equivalent safety with § 27.1549(b) for applicants using an unmarked normal operating range instead of green. Section 27.1549(b) continues to allow the green operating range to be displayed as green, but now permits an option for the normal operating range to be unmarked.
b. Procedures. The policy pertaining to these requirements, which is found in section 27.1543 of this AC, remains in effect with the following changes and additions.
For compliance with §§ 27.771(a) and 27.1549(b), electronic displays that lack green arcs must include features that permit the pilot to easily interpret (by way of glancing at the instrument) whether a parameter is in a precautionary range (yellow) or beyond a limit (red). In addition, consistency in displaying all required indications should be maintained between the primary instrument and the standby instrument to reduce any confusion in the cockpit when failures require using the standby instrument.
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AC 27.1551. § 27.1551 OIL QUANTITY INDICATORS.
a. Background. This section states that each oil quantity indicator must be marked with enough increments to indicate readily and accurately the quantity of oil.
b. Procedures. There are several different ways in which the oil quantity indicator may be presented. Some of the ones more prevalent in the industry are:
(1) Oil quantity indicator. (Generally used when large amounts of reserve oil are required.)
(2) Oil quantity dip stick. (Most common method of measuring engine oil.)
(3) Oil quantity sight indicator. (Generally used for measuring transmission and gearbox oil quantities.)
c. No matter what method of oil quantity indicator is used, the indicator should be marked so that the oil quantity can be accurately determined. This can range from increments marked in gallons, such as oil quantity indicators for large amounts of oil, to oil quantity indicators marked in quarts with full and add marks, such as engine dip sticks. Sight indicators with full and add marks have been used successfully for gearboxes. Sight indicators normally do not reflect quantities. These are some of the methods currently in use to indicate the oil quantity. In all cases, those methods identified above have proved to be acceptable methods of showing compliance with the § 27.1551.
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AC 27-1B, Chg 4 3/31/2014 AC 27.1553. § 27.1553 FUEL QUANTITY INDICATOR.
a. Explanation. This section describes the markings necessary to identify the portion of unusable fuel that cannot be used in level flight. Unusable fuel may be present in a design due to the relative configuration of the fuel tank to the fuel tank outlet (e.g., sumps, unusual elevations and/or configurations dictated by aircraft contours, etc.). If the unusable fuel supply for any tank is less than or equal to 1 gallon or is less than or equal to 5 percent of the tank capacity, whichever is greater, this section does not apply.
b. Procedures. For each fuel tank which has an unusable fuel capacity exceeding 1 gallon or 5 percent of the tank capacity, whichever is greater, the following should be accomplished.
(1) Calibration computations, measurements, and/or tests should determine the zero (empty) position on the fuel quantity indicator. (reference § 27.1337).
(2) The lowest reading obtainable in level flight must be determined by computation, measurement, and/or testing.
(3) Once the instrument readings defined by paragraphs b(1) and (2) above have been determined, a red arc should be placed between the readings on the fuel quantity indicator.
(4) Appropriate notations should be made in the flight manual to define the intent of the red arc to the flightcrew (reference § 27.1585(e)).
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AC 27.1555. § 27.1555 (Amendment 27-21) CONTROL MARKINGS.
a. Explanation. Section 27.1301(b) requires that all installed equipment be labeled to identify its function and operations; however, this section provides more detailed requirements for control markings. Specific criteria are given for powerplant fuel controls, fuel quantity markings, and landing gear controls. The requirement to color emergency controls red is in this section.
b. Procedures.
(1) Section 27.1555(a) requires each cockpit control, other than flight controls whose function is not obvious, to be appropriately labeled. The primary flight controls are the cyclic, collective, and the directional control (tail rotor) pedals. For the control to be appropriately labeled, the rule requires that there should be an obvious and clear demarcation of the function and operation of the control. When performing the evaluation to determine the adequacy of markings, remember that only those controls which are quite traditional should be judged to be obvious in their operation. An example of this has been the navigation/communication (NAV/COMM) control heads.
The more traditional control units had concentric knobs of decreasing size for the selection of frequency. Because this system was so common for such a period of time, the finding was generally made that the function of this control was obvious and thus did not require a specific marking. However, as more current technology digital electronic controls were used, the frequency selectors were judged not to be obvious in their operation, and their function and operation were required to be labeled.
(2) Review design data and available hardware to ensure the powerplant fuel controls are clearly and permanently marked such that:
Selector valve control clearly shows each position for each tank and each crossfeed configuration.
(ii) Tank selection sequences required for safe operation are clearly and permanently marked on or adjacent to the required selector.
(ili) Each control valve is clearly marked to show the position of the controls for each engine on multiengine rotorcraft.
(3) Review design data and available hardware to ensure that usable fuel capacity is clearly marked as follows:
If the fuel system has no selector controls, usable fuel capacity must be shown on the fuel quantity indicator (reference paragraph AC 27.1553).
(II) If the system has selector controls, the usable fuel capacity at each selector position must be clearly shown near the selector position.
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AC 27-1B, Chg 4 3/31/2014
(4) Markings of essential visual position indicators must be obvious and within view of required crewmembers. Landing gear markings normally include indications for down, intermediate/unsate, and up. Accepted symbology has included arrows for up/down indications, crosshatching of intermediate/unsafe, various combinations of colored lights, and combinations of all of the above. Cockpit presentation is further discussed in paragraph AC 27.729. Emergency controls which should be marked in red include those used for firewall/emergency fuel shutoff, landing gear blowdown/emergency release, fire extinguishers, float activation, cargo hook release and fuel dump. The method of operation of emergency controls must be clearly marked. In the case of switches and buttons, the method of operation is often inherently obvious without dedicated labeling.
(5) The two most obvious means of displaying landing gear operating speed are use of a placard or an appropriate mark in the airspeed indicator.
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AC 27.1555A. § 27.1555 (AMENDMENT 27-51) CONTROL MARKINGS.
a. Explanation. Amendment 27-51 changed the requirements for marking the usable fuel capacity for designs that have no selector controls. The previous requirement for marking the usable fuel capacity near the fuel quantity indicator is not practical for modern glass cockpit designs.
With older, electro-mechanical designs, the actual fuel capacity was not marked on the fuel quantity gage. Traditionally these designs used a placard indicating the usable fuel capacity next to the fuel quantity indicator to assist with flight planning and refueling.
Modern glass cockpit designs provide digital indication of the remaining usable fuel quantity at all times while the total usable fuel capacity is typically included, although not required, within the rotorcraft flight manual.
b. Procedures. All of the policy pertaining to this section remains in effect with the following changes:
Section 27.1555(c)(1) requires that, for fuel systems having no selector controls, the usable fuel capacity of the system be indicated at the fuel quantity indicator unless the system capacity is provided by another system or equipment readily accessible to the pilot. Such information may be provided digitally on a multi-function display (MFD) synoptic page such as the fuel system or aircraft weight and balance page. In addition to the digital representation, § 27.1555(c)(1)(ii) requires that the fuel system capacity be contained in the limitations section of the rotorcraft flight manual. The digital display of the fuel system capacity used in conjunction with the total usable fuel quantity provided in the rotorcraft flight manual limitations section will permit the flight crew to approximate endurance and will assist with refueling. Alternately, for designs that do not provide a digital readout of the usable fuel capacity and include the information in the rotorcraft flight manual, the total usable fuel capacity must be displayed at the fuel quantity indicator in accordance with § 27.1555(c)(1).
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AC 27-1B, Chg 4 3/31/2014 AC 27.1557. § 27.1557 (Amendment 27-11) MISCELLANEOUS MARKINGS AND PLACARDS.
a. Explanation. Placards or equivalent markings that are conspicuous and durable are required to identify design/operational limits or information for certain seats, baggage/cargo compartments, ballast, fuel and oil tanks, and emergency exits. The color red is specified for exit placards.
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(1) Baggage, cargo and ballast markings must state the allowable maximum weight and the distributed (floor) loading, where appropriate. The markings should prevent overloading the compartment and its floor or the ballast installation.
(2) Seats must be permanently marked as prescribed with the design allowable occupant weight if the seat is designed for less than a 170-pound occupant. The placard specified here is not related to a rotorcraft operating weight or loading limitation.
(3) Fuel and oil tank filler openings must be marked as prescribed to provide essential information for proper fluids and to provide limitation data for pressures in refueling/defueling systems if installed.
(4) Emergency exit placards or markings, inside and outside, shall be red (red with white background for visibility or reversed colors). Locating signs and operating signs or placards are required. See paragraph AC 27.783 (§ 27.783) for door marking requirements.
(5) Markings must be conspicuous and durable as prescribed in § 27.1541(b).
b. Procedures.
(1) The type design drawings such as general "markings" drawing should be reviewed for compliance. During an interior/exterior compliance inspection, usually conducted prior to issuing the TIA, compliance with the standard should be confirmed or ensured. If an FAA/AUTHORITY conducted F&R program is prescribed, complete "production" aircraft markings should be installed prior to beginning the program. As a continuation of the FAA/AUTHORITY evaluation, the markings shall be checked during the F&R program. Contrasting colors are essential. Various paint schemes should be checked for compliance.
(2) Allowable maximum weight and floor distributed loading and possibly baggage tiedown and security instructions are generally included in the cargo compartment markings. A placard, stencil, or equivalent that is conspicuous and durable may be placed on the compartment door, wall, etc.
(3) For fuel and oil filler markings, contrasting colors between letters and background are essential. The visibility of the markings should not be affected by changing paint schemes or colors. This may be accomplished by decals having a contrasting background. Stencil markings should be discouraged for fuel and oil markings.
(4) Emergency exit marking performance standards are also contained in paragraph AC 27.807. It is recommended that the exit locating sign (interior) be readable from the farthest seat in the cabin and that the identification of the operating handle or device and the operating instructions be readable from a distance of 30 inches. It is further recommended that external exit instructions or markings have Page G - 29
contrasting colors that comply with § 29.811 and have at least 30 percent difference in reflectance. Advisory Circular 20-47, Exterior Colored Band Around Exits on Transport Airplanes, provides information about measuring reflectance of colors. The standard concerns a qualitative or objective standard, however.
(5) Advisory Circular 20-116, Marking Aircraft Fuel Filler Openings with Color-Coded Decals, concerns color-coded decals for fuel filler openings. These decals generally supplement the markings required by the certification standards.
AC 27.1559. § 27.1559 (Amendment 27-21) LIMITATIONS PLACARD.
a. Explanation.
(1) The content of and information on the placard has been changed significantly as a result of associated and complementary changes in the airworthiness standards and the maintenance and operating rules. Regardless of content, the placard must be in clear view of the pilot (or pilots).
(2) By adoption of FAR Part 27 in 1965, the standard and its predecessor CAR Part 6, required compliance with the operating limitations in the approved Rotorcraft Flight Manual.
(3) In conjunction with the adoption of an Airworthiness Limitations Section for the maintenance manual as stated in § 27.1529 of Amendment 27-3, the content of the placard was changed significantly to require compliance with the requirements in that section. The maintenance rule (§ 43.16) was also adopted in 1968.
(4) Amendment 27-8 adopted standards to allow use of a combination of manual material, markings, and placards rather than mandate a Rotorcraft Flight Manual. The requirement for the placard content was revised accordingly.
(5) Amendment 27-18, issued in 1980, adopted standards requiring "Instructions for Continued Airworthiness" (maintenance manual). This manual may include an Airworthiness Limitations Section, which is a segregated and approved part of the manual. The maintenance and operating rules, §$ 43.15, 43.16, 91.163(c) and other operating rules require compliance with the Airworthiness Limitations Section.
Similarly, other airworthiness standards were adopted for airplanes, engines, and propellers to require Instructions for Continued Airworthiness and an Airworthiness Limitations Section. See paragraph AC 27.1529 for further information.
(6) Amendment 27-21 adopted a significant change for the placard. The placard must be in clear view of the pilot and must provide a convenient cockpit presentation of the approved types of operation for each aircraft. Other operating and maintenance rules referenced in the previous paragraph provided the basis for much of this reduction in the placard content.
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9/30/99/ AC 27-1B
b. Procedures.
(1) The placard must specify the kinds of operations, such as VFR, IFR, day, night, or icing for which the rotorcraft is equipped and approved.
(2) A placard (or durable decal) must be legible to the pilot and located in clear view of the pilot. If two pilots are required, a single placard may satisfy the standard.
This aspect will be evaluated by a test pilot. The TIR should contain a compliance check entry for this section.
(3) The placard content for older rotorcraft designs is directly related to the rotorcraft certification basis. If the rotorcraft type design has an "FAA/AUTHORITY approved" and segregated Airworthiness Limitations Section of the maintenance manual, the limitations placard may be revised to comply with the new standard. The certification basis should be changed in conjunction with the placard change.
AC 27.1561. § 27.1561 SAFETY EQUIPMENT.
a. Explanation. This standard requires identification or location markings for each item of safety equipment and operating information for crew-operated controls.
b. Procedures.
(1) Release devices, such as levers or latch handles for liferafts and other safety equipment, should be plainly marked. The method of operation should be marked also. Stencils, permanent decals, placards, or other permanent labels or instructions may be used.
(2) Lockers, compartments, or pouches used to house safety equipment, such as life vests, should be marked to identify the equipment therein and to also identify, if not obvious, the method or means of getting to or releasing the equipment.
(3) Safety equipment labels and instructions should be used.
Section 27.1555(d)(2) concerns emergency control markings. White letters and red background (or reverse) should be used.
(4) Locating signs for equipment should be legible in daylight from the furthest-seated point in the cabin or should be recognizable from a distance equal to the width of the cabin. Letters, 1 inch high, should be acceptable to satisfy the recommendation. Operating instructions should be legible from a distance of 30 inches.
These are recommendations based on exit standards of § 29.811(b) and (e) (1).
(5) Easily recognized or identified and easily accessible safety equipment located in view of the occupants may not require locating signs, stencils, or decals.
Passenger compartment fire extinguisher in view of the passengers is an example.
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AC 27.1565. §27. 1565 (Amendment 27-2) TAIL ROTOR.
a. Explanation.
(1) This standard concerns tail rotor disc visibility in normal daylight ground conditions. Amendment 27-2 added "daylight" to the standard. A personnel guard is not required. The tail rotor shall be marked to achieve a conspicuous disc whenever the blades are rotating.
(2) Completely shrouded or protected blades may not require contrasting color segments if the shroud provides equivalent protection for personnel on the ground. A simple tubular guard does not alleviate this standard.
b. Procedures.
(1) Each tail rotor blade shall be marked with contrasting colors.
(2) During FAA/AUTHORITY compliance inspections or during the flight test program, the tail rotor will be evaluated, qualitatively, in daylight for a conspicuous disc.
(3) As an aid to select proper colors for conspicuousness, see AC 20-47, Exterior Colored Band around Exits on Transport Airplanes. This AC concerns, in part, methods for measuring reflectance (3:1 factor) and contrast colors for transport aircraft.
Section 29.811(b)(2) requires contrast colors for transport rotorcraft. This AC also contains suggestions for chromatic contrast. A 3:1 reflectance factor between rotor blade segment colors is acceptable. It is recommended that a few combinations of colors be approved to provide a selection of color combinations. The type design drawings will include the necessary information and data for design control.
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