(iv) Extended overwater operations (ditching).
(v) External load operation.
(8) Limiting heights and speeds are determined under § 27.79 and are presented in the form of a height versus velocity diagram in the performance information section.
(9) Often other limitations are included in the limitations section that are not specifically mentioned in the rules but which are necessary for safe operation.
Examples are:
(i) Altitude limits.
(ii) Ambient temperature limits.
(iii) Conditions for use of rotor brake.
(iv) Prohibitions against prolonged hover in cross or tail winds to prevent accumulation of noxious fumes in cockpit or cabin.
(v) Prohibitions against acrobatic maneuvers.
(vi) Required placards including text and location.
(vii) Special airworthiness equipment installations such as engine out or low rotor RPM warning systems.
AC 27.1585. § 27.1585 (Amendment 27-16) OPERATING PROCEDURES.
a. Explanation. The procedures sections of the manual should contain essential information peculiar to the particular type or model, the knowledge of which may be expected to enhance safety in the kinds of operations for which the type or model is approved. Information or procedures not directly related to airworthiness, or not under control of the crew, should not be included, nor should any procedure which is accepted as basic airmanship.
(1) Procedures information should be presented with respect to normal and emergency procedures. Alternatively, information outside the category of normal procedures may be subdivided into categories described as “abnormal” procedures and “emergency” procedures, as described herein.
(2) Notes, cautions, and warnings may be used to emphasize specific instructions or information in general accord with the following.
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(i) “Note” should be used with respect to matters not directly related to safety but which are particularly important (e.g., Note: For normal twin-engine operation, maximum permissible torque needle split is 4 percent total).
(ii) “Caution” should be used with respect to safety matters of a secondary order not immediately imminent (e.g., Caution: On engine restart reduce ITT to 750° C on the operating engine).
(iii) “Warning” should be used with respect to safety matters of a primary order or immediately imminent (e.g., Warning: Do not allow rotor RPM to drop below minimum limits).
(3) The operating procedures of this section have been developed with specific regard for the design features and operating characteristics of the rotorcraft and have been approved by FAA/AUTHORITY for guidance in identifying acceptable procedures for safe operation. Observance of these procedures is not mandatory, and FAA/AUTHORITY approval of such procedures is not intended to prohibit or discourage development and use of improved or equivalent alternate procedures based on operational experience with the rotorcraft. When alternate procedures are used, full responsibility for compliance with applicable airworthiness safety standards rests with the operator.
b. Procedures. Procedural information should be presented in substantial accord with the categories described below:
(1) Normal Procedures. Normal procedures are concerned with peculiarities of the rotorcraft design and operating features encountered in connection with routine operations, including malfunction cases not considered in the other procedures section
(i.e., not considered to degrade safety). Material conforming to the above should be presented for each phase of flight, following in sequence from preflight through engine shutdown, and should include, but not be limited to, systems operation (including fuel system information prescribed in § 27.1585(b)), missed approaches, balked landings, etc.
(2) Emergency Procedures.
(i) Malfunction or abnormal procedures are included in many flight manuals to provide corrective crew actions that are not as urgent as those in the Emergency Procedures sections. These procedures are concerned with foreseeable situations, usually entailing a failure condition, in which the use of special systems, or the alternate use of regular systems, may be expected to maintain an acceptable level of safety. Typical examples of events considered to entail abnormal procedures are engine failure or conditions that require an engine shutdown (under flight conditions where the failure is not critical), stopping and restarting engines in flight, extending Page G - 43
AC 27-1B, Chg 2 4/25/06 landing gear or flaps by alternate means, approach in multiengine aircraft with inoperative engine(s), etc.
(ii) Emergency procedures are concerned with foreseeable but unusual situations in which immediate and precise action by the crew, as detailed in the recommended procedures, may be expected to reduce substantially the risk of disaster.
Typical examples of incidents considered to be emergencies are fire, ditching, loss of tail rotor thrust or control, etc. It is expected that, in the case of tail rotor failure, the emergency procedures will have been validated by analysis, simulation, or any relevant service experience. The analysis or simulation of the tail rotor control failure procedures may be validated where practical by limited flight test.
(iii) Amendment 27-11 added ditching standards to Part 27. When ditching approval is requested, appropriate procedures and information will be included in the manual. Scale model tests are generally used to prove autorotation “ditching” characteristics and to prove stability in the water (capsize threshold) of the rotorcraft type design. Many rotorcraft designs require emergency float bags that deploy either before water contact or shortly after water contact to provide the flotation and stability necessary to comply with the requirements.
(A) Autorotation altitudes and airspeeds and water contact information, if appropriate, derived from or used during the ditching model tests, should be confirmed during FAA/AUTHORITY flight tests and should be included in the manual. Information concerning sea states or wave height to length ratios, investigated and found satisfactory, may be included in the manual if nonsevere sea states are likely to be exceeded.
(B) Instructions for deploying liferafts may be needed for certain designs.
For example, if liferafts are stowed outside the cabin, special instructions may be necessary.
(iv) Evacuation Procedures for Rotorcraft Litter Configurations.
Appropriate procedures and minimum crew requirements should be considered and included in the manual or manual supplement, if necessary, to assure timely evacuation.
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(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:
(1) 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 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.
(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 subs ection 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 the performance decrement resulting from the actual tail wind component.” 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.
(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., 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 the performance decrement resulting from the actual tail wind component." 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 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 27-1B, Chg 9 AC 27.1587B. § 27.1587 (AMENDMENT 27-51) PERFORMANCE INFORMATION.
a. Explanation. Amendment 27-51 changed the term “height-speed” to “heightvelocity” in paragraph (a)(1) of § 29.1587 to be consistent with the title nomenclature of § 29.87, which was changed from “Limiting height-speed envelope” to “Height-velocity envelope” at amendment 29-39.
b. Procedures. The policy pertaining to the procedures in this section remains in effect. For purposes of this AC, the terms “height-velocity” and “height-speed” are 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 function 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.
(i) 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.
(iii) 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.
(viii) 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.
(i) 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.
(ii) 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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