(3) The use of illustrations to show controls, instruments, explain systems, etc., is encouraged.
(4) If the unusable fuel supply in any tank exceeds 5 percent or 1 gallon, whichever is greater, a statement should appear in the normal procedures section to warn the pilot that the quantity of fuel remaining in the tank when the gauge reads zero is not usable in flight.
AC 27.1585A. § 27.1585 (Amendment 27-21) OPERATING PROCEDURES.
a. Explanation. Amendment 21 to the regulation adds the requirement to present the airspeeds and type of landing surface used in takeoff and landing tests.
Additionally, the airspeeds and rotorspeeds for minimum rate of descent and best glide in autorotation at maximum gross weight should be presented in the Rotorcraft Flight Manual (RFM).
b. Procedures. All of the policy material pertaining to this section remains in effect with the following additions:
Takeoff and landing procedures and speeds and the kind of surface used in takeoff and landing tests should be presented in the Normal Procedures section of the RFM.
(2) The airspeeds and rotor speeds corresponding to minimum rate of descent and maximum gliding distance in autorotation should be included in the Emergency Malfunction section of the RFM.
AC 27.1587. § 27.1587 (Amendment 27-21) PERFORMANCE INFORMATION.
[See new AC 27.1587A (dated 9/17/2009) posted as separate document in RGL with this Master AC.]
a. Explanation.
(1) This section contains the performance information necessary for operation R Part 27 and apreab in compliance with applicable performance requirements of FAR Part 27 and applicable special conditions together with additional information and data essential for implementing pertinent operational requirements.
(2) Performance information and data may be presented for the range of weight, altitude, temperature, and other operational variables stated as operational performance limitations. It is recommended that performance information and data be presented substantially in accordance with the following paragraphs. Where applicable, reference to the appropriate requirement of the certification or operating regulation should be included.
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(i) General. Include all descriptive information necessary to identify the configuration and conditions for which the performance data are applicable. Such information may include the complete model designations of rotorcraft and engines, definition of installed rotorcraft features, and equipment that affects performance together with the operative status thereof. This section should also include definitions or terms used in the performance section (i.e., IAS, CAS, ISA, configuration, etc.) plus calibration data for airspeed, altimeter, ambient air temperature, and other information of a general nature.
Performance Procedures. The procedures, techniques, and other conditions associated with obtainment of the flight manual performance should be included. The procedures may be presented as a performance subsection or in connection with a particular performance graph. In the latter case, a comprehensive listing of the conditions associated with the particular performance may serve the objective of "procedures" if sufficiently complete. Performance figures are based on the minimum installed specification engine.
(i) Wind Accountability. Wind accountability may be utilized for determining takeoff and landing field lengths. This accountability may be up to 100 percent of the minimum wind component along the takeoff or landing path opposite to the direction of takeoff. Wind accountability data presented in the RFM should be labeled "UNFACTORED" (if 100 percent accountability is taken) and should be accompanied by the following note: "Unless otherwise authorized by operating regulations, the pilot is not authorized to credit more than 50 percent of the performance increase resulting from the actual headwind component and must reduce performance by 150 percent of the performance decrement resulting from the actual tail wind component.i In some rotorcraft, it may be necessary to discount the beneficial aid to takeoff performance for winds from zero to 10 knots. This should be done if it is evident that the winds from zero to 10 knots have resulted in a significant degradation to the takeoff performance due to flight through the main rotor vortex. Degradation may be determined by determining the power required to fly, by reference to a pace vehicle, at speeds of 10 knots or less.
(iv) The following list is illustrative of the information that may be provided for a normal category rotorcraft.
(A) Density altitude chart for converting from pressure to density altitude.
(B) Airspeed calibration (calibrated vs. true indicated airspeed) for level flight.
(C) Hover performance charts both in and out-of-ground effect with instructions for their use. The out-of-ground effect hover performance chart is not required but may be useful.
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(D) For turbine-powered rotorcraft in all categories, a power assurance check chart.
(E) A statement of the maximum crosswind and downwind components that have been demonstrated as safe for operation near the ground.
(v) Miscellaneous Performance Data. Any performance information or data not covered in paragraphs AC 27.1587a(2) (iv)(A) through (E) above, but considered necessary or desirable to enhance safety or to enable application of the operating regulations, should be included.
(vi) Flightcrew Notes. It is recommended that provisions be made in the "unapproved" portion of the Rotorcraft Flight Manual for inclusion of information and data of a type that is useful or desirable for operation of the rotorcraft but is not approved by FAA/AUTHORITY. (Material in this section should be consistent with material in the approved portion of the manual.)
b. Procedures. None.
AC 27.1587A. § 27.1587 (Amendment 27-44) Performance Information.
a. Explanation. Amendment 27-44 added the requirement to include in the Rotorcraft Flight Manual (RFM), the weight at the maximum takeoff and landing altitude for which the rotorcraft can safely hover out-of-ground-effect (OGE) in winds of at least 17 knots in all azimuths. This change is in conjunction with the new demonstration requirements of § 27.143(d). Additionally, this change makes clear that the in-groundeffect (IGE) performance with winds of at least 17 knots be included in the RFM.
All the policy material pertaining to this section remains in effect with the following changes:
(1) This section contains the performance information necessary for operation in compliance with applicable performance requirements of part 27 and applicable special conditions together with additional information and data essential for implementing pertinent operational requirements.
(2) Information on limiting height/speed envelope must be given up to at least 7,000 feet as required in § 27.79. Giving information on limiting height/speed envelope at altitudes over 7,000 feet is desirable but not mandatory. For this information it is permissible to use a different extrapolation method, provided there is technical data to back it up.
(3) Performance information and data may be presented for the range of weight, altitude, temperature, and other operational variables stated as operational performance limitations. It is recommended that substantial performance information and data be presented per the following paragraphs. Where applicable, reference to Page G - 47
AC 27-1B, Chg 4 9/17/2009 the appropriate requirement of the certification or operating regulation should be included.
(1) General. Include all descriptive information necessary to identify the configuration and conditions for which the performance data are applicable. Such information may include the complete model designations of rotorcraft and engines, definition of installed rotorcraft features, and equipment that affects performance together with the operative status thereof. This section should also include definitions or terms used in the performance section (i.e., indicated airspeed (IAS), calibrated airspeed (CAS), international standard atmosphere (ISA), configuration, etc.) plus calibration data for airspeed, altimeter, ambient air temperature, and other information of a general nature.
(ii) Performance Procedures. The procedures, techniques, and other conditions associated with obtainment of the flight manual performance should be included. The procedures may be presented as a performance subsection or in connection with a particular performance graph. In the latter case, a comprehensive listing of the conditions associated with the particular performance may serve the objective of "procedures" if sufficiently complete. Performance figures are based on the minimum installed specification engine.
(iii) Wind Accountability. Wind accountability may be utilized for determining takeoff and landing field lengths. This accountability may be up to 100 percent of the minimum wind component along the takeoff or landing path opposite to the direction of takeoff. Wind accountability data presented in the RFM should be labeled "UNFACTORED" (if 100 percent accountability is taken) and should be accompanied by the following note: "Unless otherwise authorized by operating regulations, the pilot is not authorized to credit more than 50 percent of the performance increase resulting from the actual headwind component and must reduce performance by 150 percent of zero to 10 knots have resulted in a significant degradation to the takeoff performance due to flight through the main rotor vortex. Degradation may be determined by ascertaining the power required to fly, by reference to a calibrated pace vehicle, at speeds of 10 knots or less.
(iv) The following list is illustrative of the information that may be provided for a normal category helicopter.
(A) Density altitude chart for converting from pressure to density altitude.
(B) Airspeed calibration (calibrated vs. true indicated airspeed) for level flight.
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(C) Hover performance charts both IGE and OGE with instructions for their use.
(D) For turbine-powered helicopters in all categories, a power assurance check chart.
(E) A statement of the maximum crosswind and downwind components that have been demonstrated as safe for operation both IGE and OGE.
(v) Miscellaneous Performance Data. Any performance information or data not covered in AC 27.1587.a.(3) (iv)(A) through (E) above, but considered necessary or desirable to enhance safety or to enable application of the operating regulations, should be included.
(vi) Flightcrew Notes. Recommend that provisions be made in the "unapproved" portion of the RFM for inclusion of information and data of a type that is useful or desirable for operation of the rotorcraft; but is not approved by FAA/AUTHORITY. (Material in this section should be consistent with material in the approved portion of the manual.)
b. Procedures. None.
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AC 27.1587B. § 27.1587 (AMENDMENT 27-51) PERFORMANCE INFORMATION.
a. Explanation. Amendment 27-51 changed the term "height-speed" to "heightenvelope" at amendment 29-39.
effect. Por puduses The is Ac, tentaring in en recodie ain there on remains in equivalent.
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AC 27-1B, Chg 4 3/31/2014 AC 27.1589. § 27.1589 LOADING INFORMATION.
a. Explanation. Control of the rotorcraft weight and balance is an operational tunction and is the responsibility of the operator. However, instructions necessary to enable loading of the rotorcraft within the established limits of weight and center of gravity and to maintain the loading within such limits are required by the operating regulations, and inclusion of such loading instructions in the Rotorcraft Flight Manual is required by this rule. Approved loading instructions, therefore, must be presented in the Rotorcraft Flight Manual and, at the option of the applicant, may be included in the approved portion or in the unapproved portion.
b. Procedures.
(1) For the purpose of the flight manual, distinction is made here between the loading instructions required by the certification requirements of Part 27 and the weight and balance data required by the operating requirements. The former prescribed information is applicable to the rotorcraft type and is subject to FAA/AUTHORITY approval as flight manual material.
(2) For compliance with the noted requirements, it is necessary for the applicant to develop weight and balance data and loading instructions as necessary to satisfy the needs of both certification and operation. In order to consolidate in one document information on rotorcraft loading, it is recommended that the weight and balance data be developed to include appropriate loading instructions, and that both be included in the Rotorcraft Flight Manual as an "unapproved" section entitled "Weight and Balance." Such a section should include the following statement as a note: "In accordance with FAA/AUTHORITY procedures, the detail weight and balance data of this section are not subject to FAA/AUTHORITY approval. The loading instructions of this section, however, have been approved by FAA/AUTHORITY as satisfying all requirements for instructions on loading of the rotorcraft within approved limits of weight and center of gravity and on maintaining the loading within such limits."
(3) For initial approval of the manual, an actual or specimen weight and balance section should be submitted for evaluation and approval of the loading instructions. Weight and balance data for each particular rotorcraft need not be submitted for approval as flight manual material unless a substantive change is made to the approved loading instructions.
(4) The weight and balance material outlined below is believed to be adequate for rotorcraft with conventional loading and fuel-management techniques. For rotorcraft which necessitate redistribution of fuel (other than normal consumption) to maintain loading within prescribed limits, the material should be amplified as necessary.
Weight Limits. A list and explanation, where necessary, of all fixed-weight limitations should be included.
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(ii) Center of Gravity Limits. The approved center of gravity ranges should be presented with due accounting for landing gear position.
(II) Dimensions and Datum Line Locations. The dimensions and relative location of rotorcraft features associated with weighing and loading of the rotorcraft and with weight and balance computations should be described and/or illustrated.
(iv) Equipment List. The rotorcraft should be defined or described sufficiently to identify the presence or absence of optional systems, features, or installations that are not readily apparent. In addition, all other items of fixed and removable equipment included in the empty weight should be listed.
(v) Fuel and Other Liquids. Fuel and other liquids, including passenger-service liquids that are included in the empty weight, should be identified and listed together with information necessary to enable ready duplication of the particular condition.
(vi) Weight Computations. Computations of the empty weight and empty-weight CG location should be included.
(vii) Empty Weight and Empty-Weight Center of Gravity Location.
Statement of these values should be included.
(vili) Loading Schedule. Loading schedule should be included, if appropriate.
(ix) Loading Instructions. Complete instructions relative to the loading procedure, or to use the loading schedule, should be included.
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CHAPTER 3
AIRWORTHINESS STANDARDS
NORMAL CATEGORY ROTORCRAFT
MISCELLANEOUS GUIDANCE (MG) AC 27 MG 1. CERTIFICATION PROCEDURE FOR ROTORCRAFT AVIONICS EQUIPMENT.
a. Pretest Requirements.
(1) General. This test guideline has been prepared as an aid in the evaluation of rotorcraft avionics (aviation electronics) equipment installations. The criteria presented are not exclusive, but are offered as one method of evaluating design practice and performance. Consider the testing and qualification of an electronic installation as consisting of three phases: preinstallation, ground, and flight. The amount of testing necessary during each phase will vary with the amount of testing performed on previous phases. For example, if a system is produced under a TSOA, pre-installation performance relative to TSO functions is likely substantiated. Therefore, the ground and flight test to assess these functions may be able to be reduced. However, a TSOA does not mean that the specific system meets installed performance requirements per 14 CFR part 27. In addition, a thorough ground testing program should result in reduction in necessary flight testing. When the operating or airworthiness regulations require a system to perform its intended function, we strongly recommend the use of TSO'd equipment or the submission of data substantiating the equipment performance.
(2) Regulatory References. Sections 27.1301 and 27.1309 (through Amendment 27-19).
(3) System Design. Sufficient data should accompany systems or equipment presented for installation approval, when not qualified by TSO or other approval means, to substantiate the design acceptability.
(1) Operation of Controls. The operation of controls intended for use during flight, in all possible position combinations and sequences, should not result in a condition that would be detrimental to the continued safe performance of the system.
(Il) Electrical Shock. Design systems to minimize the risk of dangerous electrical shock under all probable conditions.
(III) Fire Hazard. The design of the system should be such that all components meet the applicable fire and smoke protection requirements of §§ 27.853 and 27.863. Cables and equipment for installation in designated fire zones used during emergency procedures should be fire resistant.
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AC 27-1B, Chg 7 2/4/2016
(iv) Plugs and Cables. Connector pins for sensitive signal circuits should not be adjacent to pins used for ac power circuits. If redundant wiring is used to comply with systems regulations such as § 27.1309, the wires should be routed through separate plugs or cables with as much physical separation as practicable. The system design should eliminate possible incorrect mating of plugs. Minimize electromagnetic interference by using cable grounding and shielding techniques.
(4) System Performance. Where the operating or airworthiness regulations require a system to perform its intended function, and when the equipment is not qualified by TSO or other approval means, performance data furnished to the FAA AUTHORITY can reduce the installed performance testing. The appropriate TSO minimum performance standard may be useful as a guide.
(i) Environment. An appropriate means for environmental testing is set forth in Radio Technical Commission for Aeronautics (RTCA) Document DO-160. Applicants should submit test reports showing that the laboratory-tested categories, such as temperature, vibration, altitude, etc., are compatible with the environmental demands placed on the rotorcraft.
(ii) Failure Analysis. Section 27.1309(b) requires consideration of system malfunctions or failures.
(5) Installation Design.
(i) Mechanical Installation. Installations should ensure compliance with airworthiness regulations and comply with the equipment manufacturer's recommendations. The designer should observe good engineering practices in specifying material type, thickness, fastener type, edge distance, and attachment to the equipment rack. By analysis or static tests, the mounted equipment should be shown to withstand the inertia forces of §§ 27.561 (b)(3) and 27.337. Refer to AC 43.13-2 (current version) for static test procedures.
(ii) Arrangement and Visibility. The mounting position of all instruments, switches, position labels, and control heads should make them plainly visible to the pilot while in his normal, panel-facing position and under all cockpit lighting conditions likely to occur. TSO approval does not assure instruments will be acceptable in a particular cockpit installation or for all lighting conditions. The instruments, switches, and placarding must be free from reflections. Malfunction annunciation devices should be conspicuous and clearly visible to the pilot. (See §§ 27.1321, 27.771, 27.1381,
27.1555(a) and AC 20-69.)
(iii) Load Analysis.
(A) Power sources. It should be determined whether the electrical power source capacity is adequate for the system installation under all foreseeable operating conditions including engine failure on multiengine rotorcraft. Apply system load Page MG 1 -2
reductions or increase power source capacity, if necessary, to assure compatibility between load and source. If duplicate systems are required, power them from separate buses.
(B) Navigation course deviation circuit loading. It should be determined that its load matches the impedance of the deviation circuit source and does not exceed the source capacity. Consider the transfer loads when the system is capable of transfer (§ 27.1301).
(C) Malfunction indicator circuit loading. It should be determined that its load matches the impedance of the malfunction indicator source and does not exceed the source capacity. Consider the transfer loads when the system is capable of transfer (§ 27.1301).
(D) Synchro signal loading. When adding parallel loads to synchros, review the manufacturers' specifications to assure that the additional loads do not result in an overloaded synchro.
(iv) Interface. In many cases, different manufacturers design the mating units of a system. For example, a brand-X gyro may be designed for operation with a brand-X flight director, but later a modifier decides to operate a brand-Y autopilot with the brand-X gyro. This applies just as well to navigational (NAV) receivers, Area NAV (RNAV) units, course indicators, omni bearing selectors, tachometer indicators, transmitters, and many other equipment items. When this is the case, the applicant should provide data, in summarized form, describing those characteristics such as impedance, volts, etc., that are necessary to ensure a compatible and reliable system.
The data should also reference the source of the interface data (§ 27.1301).
(v) Flight Tests. An FAA/AUTHORITY engineering flight test is required during type certification or after modification that changes the established limitations, flight characteristics, or performance of a rotorcraft or any of its required systems or operating procedures. Appropriate flight test personnel should evaluate new installations of equipment in the cockpit or modifications that affect existing equipment in the cockpit, if it is necessary to evaluate operational aspects of the change. If the applicant opts to darken the windows, evaluate the cockpit arrangement, placards, markings, instrument visibility, and light reflections on the ground, where possible.
Conduct electromagnetic compatibility tunctional checks, windshield glare, and pilot workload evaluations in flight at the FAA/AUTHORITY flight test pilot's option.
(vi) Radio Master Switches. Some installations incorporate radio master switches to control special busses for the avionics systems. If providing this capability, evaluate it to ensure no introduction of failure modes that will result in excessive or even total loss of all required avionics. One switch that controls all required avionics is unacceptable for instrument flight rules (IFR) installations. The evaluation should include an assessment of the loss of the systems to be included on the radio master switches), and the subsequent effect on continued safe flight.
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AC 27-1B, Chg 7 2/4/2016
b. Test Procedures. Where the airworthiness or operating regulations require a system to perform its intended function, and not create a hazard to other required systems, accomplish sufficient testing to ensure satisfactory performance. When ground testing is not sufficient to evaluate a system's performance properly, accomplish flight testing. Acceptable flight test criteria for specific navigation and communication equipment are contained herein. If seeking IFR operations approval for the rotorcraft, satisfy the additional criteria of section AC 27 Appendix B of this AC.
(1) VHF Systems.
(i) General. Provide intelligible communications between the rotorcraft and ground facilities throughout the airspace within 80 nautical miles (NM) of an FAA/AUTHORITY ground facility from radio line of sight altitude to the maximum altitude for which the rotorcraft is certificated. Provide communication with the rotorcraft at or above line of sight altitude in right and left bank up to 10° and on all headings.
(ii) Electromagnetic Compatibility (EMC). With all systems operating in flight, verify by observation that no adverse effects are present in the flight systems.
Complete a qualitative evaluation of VHF radio navigation and communication equipment operation. Further guidance may be found in AC 43.13-2B, Chapter 2, paragraph 209.
(III) Antenna Measurement. If provided satisfactory antenna measurement data, reduce the following flight test to checks in right and left turns near the predicted bearings of worst performance. If antenna locations are symmetrical, conduct tests using only one turn direction.
(A) Long range reception. Starting at a distance of 80 NM from the ground facility antenna, perform a right or left 360° turn at a bank angle of at least 10°.
Communicate with the ground facility every 10° of turn to test the intelligibility of the signals received at the ground station and in the rotorcraft. For 80 NM, the minimum line of sight altitude is approximately 4,000 feet.
(B) Approach configuration. With the landing gear down and with the rotorcraft in the approach configuration (at a distance of 10 NM from the ground station and in an idle power descent toward the station), demonstrate intelligible communications between the rotorcraft and the ground facility.
(2) HF Systems.
(1) Demonstrate acceptable communications by contacting a ground facility at a distance of at least 80 NM. Single sideband equipment should also perform acceptably in the amplitude modulation mode of operation.
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