CONTENTS Page No.
CHAPTER 1 - PART 21 CERTIFICATION PROCEDURES FOR
PRODUCTS AND PARTS AC 21.16 Special Conditions ...... FAR 21-1 AC 21.31 Type Design................. FAR 21-2 AC 21.33 Inspection and Tests... .FAR 21-2 AC 21.35 Flight Tests..... FAR 21-2 AC 21.39 Flight Test Instrument Calibration and Correction Report FAR 21-6 CHAPTER 2 - PART 27 AIRWORTHINESS STANDARDS:
NORMAL CATEGORY ROTORCRAFT
SUBPART A
GENERAL AC 27.1 Applicability .. A-1 AC 27.1A Applicability ... A-1
AC 27.1B ApplicabilityA-2
AC 27.2 Special Retroactive Requirements. A-2 AC 27.2A Special Retroactive Requirements A-4
SUBPART B - FLIGHT
GENERAL
AC 27.21 Proof of ComplianceB-1
AC 27.25 Weight Limits... B-3 AC 27.25A Weight Limits.. B-4 AC 27.27 Center of Gravity Limits.. B-4.2 AC 27.29 Empty Weight and Corresponding Center of Gravity. B-6.2
AC 27.31 Removable BallastB-7
AC 27.33 Main Rotor Speed and Pitch Limits B-7
PERFORMANCE AC 27.45 Performance - General. B-9 AC 27.45A General .. B-18
AC 27.45B GeneralB-18
AC 27.45C Performance - General B-18 Page No.
Page ili
AC 27.1B, Chg 9 6/23/23 SUBPART B - FLIGHT (continued) PERFORMANCE (continued) AC 27.49 Performance at Minimum Operating Speed. B-24.2 AC 27.51 Takeoff... B-25 AC 27.51A Takeoff... B-26 AC 27.65 Climb: All Engines Operating B-26.2 AC 27.65A Climb: All Engines Operating B-28 AC 27.67 Climb: One Engine Inoperative B-28 AC 27.71 Autorotation Performance B-29 AC 27.73 Performance at Minimum Operating Speed. B-32 AC 27.75 Landing ..... B-34.1 AC 27.75A Landing .. B-35 AC 27.79 Limiting Height - Speed Envelope B-37 AC 27.79A Limiting Height - Speed Envelope B-45 AC 27.87 Height-Speed Envelope. B-45 AC 27.87A Height-Velocity Envelope. B-45.1
FLIGHT CHARACTERISTICS AC 27.141 Flight Characteristics - General B-46 AC 27.143 Controllability and Maneuverability B-48 AC 27.143A Controllability and Maneuverability B-52.2 AC 27.151 Flight Controls. B-52.8 AC 27.161 Trim Control .. B-53 AC 27.171 Stability: General B-53 AC 27.173 Static Longitudinal Stability. B-54 AC 27.173A Static Longitudinal Stability. B-55 AC 27.175 Demonstration of Static Longitudinal Stability. B-58 AC 27.175A Demonstration of Static Longitudinal Stability B-60.2 AC 27.177 Static Directional Stability. B-60.6 AC 27.177A Static Directional Stability. B-60.7
GROUND AND WATER HANDLING CHARACTERISTICS AC 27.231 Ground and Water Handling Characteristics - General B-61
AC 27.235 Taxiing ConditionB-61
AC 27.239 Spray Characteristics.. B-62
AC 27.241 Ground ResonanceB-63
MISCELLANEOUS FLIGHT REQUIREMENTS
AC 27.251 VibrationB-68
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SUBPART C - STRENGTH REQUIREMENTS
GENERAL
AC 27.301 LoadsC-1
AC 27.303 Factor of SafetyC-1
AC 27.305 Strength and Deformation C-2
AC 27.307 Proof of StructureC-2
AC 27.307A Proof of StructureC-3
AC 27.309 Design LimitationsC-4
FLIGHT LOADS AC 27.321 Flight Loads - General.. C-5 AC 27.337 Limit Maneuvering Load Factor C-5 AC 27.339 Resultant Limit Maneuvering Loads C-8 AC 27.341 Gust Loads.. C-8 AC 27.351 Yawing Conditions .. C-9 AC 27.361 Engine Torque.. C-14
CONTROL SURFACE AND SYSTEM LOADS AC 27.391 Control Surface and System Loads - General. C-15 AC 27.391A Control Surface and System Loads - General C-15 AC 27.395 Control System.. C-15 AC 27.395A Control System.. C-17 AC 27.397 Limit Pilot Forces and Torques. C-17
AC 27.399 Dual Control SystemC-18
AC 27.401 Auxiliary Rotor Assemblies C-18 AC 27.401A Auxiliary Rotor Assemblies C-20 AC 27.403 Auxiliary Rotor Attachment Structure C-20 AC 27.403A Auxiliary Rotor Attachment Structure C-21 AC 27.411 Ground Clearance: Tail Rotor Guard C-21 AC 27.413 Stabilizing and Control Surfaces C-22 AC 27.413A Stabilizing and Control Surfaces C-24 AC 27.427 Unsymmetrical Loads... C-24
GROUND LOADS AC 27.471 Ground Loads - General C-28 AC 27.473 Ground Loading Conditions and Assumptions. C-28 AC 27.475 Tires and Shock Absorbers. C-29 AC 27.477 Landing Gear Arrangement C-29 Page v
AC 27.1B, Chg 4 5/1/2014 Page No.
SUBPART C - STRENGTH REQUIREMENTS (continued) GROUND LOADS (continued) AC 27.479 Level Landing Conditions C-29 AC 27.481 Tail-Down Landing Conditions C-30 AC 27.483 One-Wheel Landing Conditions C-31 AC 27.485 Lateral Drift Landing Conditions C-31 AC 27.493 Braked Roll Conditions. C-32 AC 27.497 Ground Loading Conditions: Landing Gear With Tail Wheels C-32 AC 27.501 Ground Loading Conditions: Landing Gear With Skids. C-34 AC 27.501A Ground Loading Conditions: Landing Gear With Skids. C-35 AC 27.505 Ski Landing Conditions C-35
WATER LOADS AC 27.521 Float Landing Conditions C-37
MAIN COMPONENT REQUIREMENTS
AC 27.547 Main Rotor StructureC-38
AC 27.549 Fuselage, Landing Gear, and Rotor Pylon Structure C-38
EMERGENCY LANDING CONDITIONS AC 27.561 Emergency Landing Conditions - General C-40 AC 27.561A Emergency Landing Conditions - General C-41 AC 27.561B Emergency Landing Conditions - General C-42 AC 27.561C Emergency Landing Conditions - General C-43 AC 27.562 Emergency Landing Dynamic Conditions C-44 AC 27.563 Structural Ditching Provisions C-81 AC 27.563A Structural Ditching Provisions C-81
FATIGUE EVALUATION AC 27.571 Fatigue Evaluation of Flight Structure C-83
AC 27.571A Fatigue Evaluation of Flight Structure for Category A CertificationC-86
AC 27.573 Damage Tolerance and Fatigue Evaluation of Composite.. C-88 Rotorcraft Structures Page vi
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SUBPART D - DESIGN AND CONSTRUCTION
GENERAL AC 27.601 Design... D-1 AC 27.602 Critical Parts... D-2 AC 27.603 Materials .. D-4
AC 27.605 Fabrication MethodsD-4
AC 27.607 Fasteners ... D-6 AC 27.609 Protection of Structure. D-6
AC 27.610 Lightning ProtectionD-8
AC 27.611 Inspection Provisions .. D-11 AC 27.613 Material Strength Properties and Design Values. D-13 AC 27.613A Material Strength Properties and Design Values. D-14 AC 27.619 Special Factors . D-16 AC 27.621 Casting Factors. D-17 AC 27.623 Bearing Factors. D-27 AC 27.625 Fitting Factors. D-28 AC 27.625A Fitting Factors D-29 AC 27.629 Flutter. D-29 ROTORS AC 27.653 Pressure Venting and Drainage of Rotor Blades. D-31 AC 27.659 Mass Balance.. D-31 AC 27.661 Rotor Blade Clearance. D-31 AC 27.663 Ground Resonance Prevention Means .. D-33 AC 27.663A Ground Resonance Prevention Means D-35
CONTROL SYSTEMS AC 27.671 Control Systems - General D-36 AC 27.672 Stability Augmentation, Automatic, and Power-Operated Systems... D-36 AC 27.673 Primary Flight Control .. D-37 AC 27.674 Interconnected Controls D-37
AC 27.675 StopsD-38
AC 27.679 Control System Locks.. D-40 AC 27.681 Limit Load Static Tests. D-40.1 AC 27.683 Operation Tests.. D-41 AC 27.685 Control System Details. D-41 AC 27.685A Control System Details. D-42 AC 27.687 Spring Devices .. D-43 AC 27.691 Autorotation Control Mechanism. D-43 AC 27.695 Power Boost and Power-Operated Control System D-44 Page vii
AC 27.1B, Chg 4 5/1/2014 Page No.
SUBPART D - DESIGN AND CONSTRUCTION (continued)
LANDING GEAR AC 27.723 Shock Absorption Tests D-47
AC 27.725 Limit Drop TestD-50
AC 27.727 Reserve Energy Absorption Drop Test.. D-50 AC 27.727A Reserve Energy Absorption Drop Test. D-51 AC 27.729 Retracting Mechanism D-51
AC 27.731 WheelsD-54
AC 27.733 TiresD-55
AC 27.735 Brakes...D-56
AC 27.737 Skis . D-58
FLOATS AND HULLS AC 27.751 Main Float Buoyancy... D-59 AC 27.753 Main Float Design. D-60 AC 27.755 Hulls D-60
PERSONNEL AND CARGO ACCOMMODATIONS AC 27.771 Pilot Compartment D-62 AC 27.773 Pilot Compartment View D-63 AC 27.775 Windshields and Windows D-68 AC 27.775A Windshields and Windows D-68 AC 27.777 Cockpit Controls. D-68 AC 27.779 Motion and Effect of Cockpit Controls D-69 AC 27.783 Doors . D-72.2 AC 27.783A Doors . D-74 AC 27.785 Seats, Berths, Safety Belts, and Harnesses. D-74 AC 27.785A Seats, Berths, Safety Belts, and Harnesses D-78 AC 27.785B Seats, Berths, Litters, Safety Belts, and Harnesses D-80 AC 27.787 Cargo and Baggage Compartments. D-80 AC 27.787A Cargo and Baggage Compartments. D-82 AC 27.801 Ditching .. D-82 AC 27.805 Flight Crew Emergency Exits D-91 AC 27.807 Emergency Exits .. D-91 AC 27.807A Emergency Exits .. D-93 AC 27.807B Emergency Exits . D-93 AC 27.831 Ventilation .. D-94 AC 27.833 Heaters .. D-96 Page vili
AC 27-1B, Chg 9 6/23/23 Page No.
SUBPART D - DESIGN AND CONSTRUCTION (continued)
FIRE PROTECTION AC 27.853 Compartment Interiors. D-98 AC 27.853A Compartment Interiors D-99 AC 27.855 Cargo and Baggage Compartments.. D-99 AC 27.859 Heating Systems... D-101 AC 27.861 Fire Protection of Structure, Controls, and Other Parts D-105 AC 27.861A Fire Protection of Structure, Controls, and Other Parts D-106 AC 27.863 Flammable Fluid Fire Protection D-107
EXTERNAL LOADS AC 27.865 External Load Attaching Means D-109 AC 27.865A External Load Attaching Means D-110 AC 27.865B External Loads (previously MG 12) D-111
MISCELLANEOUS AC 27.871 Leveling Marks. D-133 AC 27.873 Ballast Provisions. D-133
SUBPART E - POWERPLANT
GENERAL AC 27.901 Installation. E-1 AC 27.901A Installation E-5 AC 27.903 Engines. E-5.2 AC 27.903A Engines E-7 AC 27.903B Engines . E-9 AC 27.903C Engines. E-10.1 AC 27.907 Engine Vibration E-10.1a
ROTOR DRIVE SYSTEM AC 27.917 Design.. E-10.2 AC 27.921 Rotor Brake. E-11 AC 27.923 Rotor Drive System and Control Mechanism Tests E-12 AC 27.923A Rotor Drive System and Control Mechanism Tests E-17 AC 27.923B Rotor Drive System and Control Mechanism Tests E-18 AC 27.927 Additional Tests.. E-19 AC 27.927A Additional Tests.. E-21 AC 27.931 Shafting Critical Speeds. E-21 Page ix
AC 27-1B, Chg 4 5/1/2014 Page No.
SUBPART E - POWERPLANT (continued) ROTOR DRIVE SYSTEM (continued) AC 27.935 Shafting Joints... E-26 AC 27.939 Turbine Engine Operating Characteristics E-26
FUEL SYSTEM AC 27.951 Fuel System - General E-29 AC 27.952 Fuel System Crash Resistance.
AC 27.953 Fuel System Independence E-56 AC 27.954 Fuel System Lightning Protection E-57 AC 27.955 Fuel Flow E-58 AC 27.955A Fuel Flow E-62 AC 27.959 Unusable Fuel Supply .. E-64 AC 27.961 Fuel System Hot Weather Operation E-65 AC 27.961A Fuel System Hot Weather Operation E-67
AC 27.963 Fuel Tanks: GeneralE-67
AC 27.963A Fuel Tanks: GeneralE-68
AC 27.963B Fuel Tanks: General... E-68 AC 27.965 Fuel Tank Tests. E-69 AC 27.967 Fuel Tank Installation.. E-70 AC 27.969 Fuel Tank Expansion Space. E-72 AC 27.969A Fuel Tank Expansion Space E-72 AC 27.971 Fuel Tank Sump.. E-73 AC 27.971A Fuel Tank Sump.. E-74 AC 27.973 Fuel Tank Filler Connection E-74 AC 27.973A Fuel Tank Filler Connection E-75 AC 27.975 Fuel Tank Vents. E-76 AC 27.975A Fuel Tank Vents. E-77 AC 27.975B Fuel Tank Vents.. E-77 AC 27.977 Fuel Tank Outlet.. E-78
FUEL SYSTEM COMPONENTS AC 27.991 Fuel Pumps E-80 AC 27.991A Fuel Pumps E-81 AC 27.993 Fuel System Lines and Fittings. E-81 AC 27.995 Fuel Valves E-82 AC 27.997 Fuel Strainer or Filter ... E-82 AC 27.997A Fuel Strainer or Filter ... E-83 AC 27.999 Fuel System Drains. E-84 AC 27.999A Fuel System Drains. E-85 Page x
Page No.
SUBPART E - POWERPLANT (continued)
OIL SYSTEM AC 27.1011 Engines - General ... E-86 AC 27.1013 Oil Tanks.. E-86 AC 27.1015 Oil Tank Tests .. E-87 AC 27.1017 Oil Lines and Fittings... E-88 AC 27.1019 Oil Strainer or Filter... E-88 AC 27.1019A Oil Strainer or Filter... E-89
AC 27.1021 Oil System DrainsE-90
AC 27.1027 Transmission and Gearboxes: General. E-90
COOLING AC 27.1041 Cooling - General E-92 AC 27.1041A General . E-94 AC 27.1043 Cooling Tests. E-94 AC 27.1045 Cooling Test Procedures E-97 AC 27.1045A Cooling Test Procedures E-98
INDUCTION SYSTEM AC 27.1091 Air Induction E-99 AC 27.1091A Air Induction E-100 AC 27.1093 Induction System Icing Protection E-101 AC 27.1093A Induction System Icing Protection E-112.1
EXHAUST SYSTEM AC 27.1121 General .. E-113 AC 27.1123 Exhaust Piping .. .. E-114
POWERPLANT CONTROLS AND ACCESSORIES AC 27.1141 Powerplant Controls: General E-117 AC 27.1141A Powerplant Controls: General E-118 AC 27.1143 Engine Controls.. E-118 AC 27.1143A Engine Controls. E-119 AC 27.1143B Engine Controls. E-119 AC 27.1145 Ignition Switches. E-120 AC 27.1147 Mixture Controls.. E-120
AC 27.1151 Rotor Brake ControlsE-121
AC 27.1163 Powerplant Accessories E-122 Page No.
Page xi
AC 27-1B 029/23 6/23/23 SUBPART E - POWERPLANT (continued)
POWERPLANT FIRE PROTECTION AC 27.1183 Lines, Fittings, and Components. E-124 AC 27.1185 Flammable Fluids.. E-125 AC 27.1187 Ventilation and Drainage E-126 AC 27.1189 Shutoff Means.. E-127 AC 27.1191 Firewalls .. E-128 AC 27.1193 Cowling and Engine Compartment Covering .. E-132 AC 27.1193A Cowling and Engine Compartment Covering E-133 AC 27.1194 Other Surfaces. E-134 AC 27.1195 Fire Detector Systems.. E-135
SUBPART F - EQUIPMENT
GENERAL AC 27.1301 Function and Installation F-1 AC 27.1303 Flight and Navigation Instruments. F-1 AC 27.1305 Powerplant Instruments F-7 AC 27.1305A Powerplant Instruments F-8 AC 27.1305B Powerplant Instruments F-9 AC 27.1305C Powerplant Instruments F-11.1 AC 27.1307 Miscellaneous Equipment F-12 AC 27.1309 Equipment, Systems, and Installations.. F-13 AC 27.1309A Equipment, Systems, and Installations. F-30 AC 27.1309B Equipment, Systems, and Installations F-30.1 AC 27.1316 Electrical and Electronic System Lightning Protection F-31 AC 27.1317 High-Intensity Radiated Fields (HIRF) Protection F-32 INSTRUMENTS: INSTALLATION AC 27.1321 Arrangement and Visibility. _ F-34 AC 27.1322 Warning, Caution, and Advisory Lights F-34.2 AC 27.1323 Airspeed Indicating System F-39 AC 27.1325 Static Pressure Systems F-40 AC 27.1327 Magnetic Direction Indicator F-41 AC 27.1329 Automatic Pilot System F-41 AC 27.1329A Automatic Pilot System F-51 AC 27.1329B Automatic Pilot System and Flight Guidance System F-52.1 AC 27.1335 Flight Director Systems F-53 AC 27.1335A Flight Director Systems. F-54.1 AC 27.1337 Powerplant Instruments F-54.2 AC 27.1337A Powerplant Instruments F-54.3 Page xii
AC 27-1B Chg 9 6/23/23 Page No.
SUBPART F - EQUIPMENT (continued)
ELECTRICAL SYSTEMS AND EQUIPMENT AC 27.1351 Electrical Systems and Equipment - General. F-55 AC 27.1353 Storage Battery Design and Installation F-58 AC 27.1353A Energy Storage Systems.. F-62.1 AC 27.1357 Circuit Protective Devices F-62.13
AC 27.1361 Master SwitchF-64
AC 27.1365 Electric CablesF-65
AC 27.1367 SwitchesF-66
LIGHTS AC 27.1381 Instrument Lights.. F-67 AC 27.1383 Landing Lights.. F-67 AC 27.1385 Position Light System Installation F-68 AC 27.1387 Position Light System Dihedral Angles F-68 AC 27.1389 Position Light Distribution and Intensities F-68 AC 27.1391 Minimum Intensities in the Horizontal Plane of Forward and F-68 Rear Position Lights AC 27.1393 Minimum Intensities in Any Vertical Plane of Forward and F-68 Rear Position Lights AC 27.1395 Maximum Intensities In Overlapping Beams of Forward and F-68 Rear Position Lights
AC 27.1397 Color SpecificationsF-68
AC 27.1399 Riding LightF-68
AC 27.1401 Anti-collision Light System F-70
SAFETY EQUIPMENT AC 27.1411 General ... F-71 AC 27.1413 Safety Belts. F-73 AC 27.1415 Ditching Equipment F-74 AC 27.1419 Ice Protection .. F-75 AC 27.1435 Hydraulic Systems F-97 AC 27.1457 Cockpit Voice Recorder. F-99 AC 27.1459 Flight Recorders.. F-101 AC 27.1461 Equipment Containing High Energy Rotors. F-103
SUBPART G - OPERATING LIMITATIONS AND INFORMATION AC 27.1501 General.. G-1 Page xiii
AC 27.1B, Chg 9 6/23/23 Page No.
SUBPART G - OPERATING LIMITATIONS AND INFORMATION (continued)
OPERATING LIMITATIONS AC 27.1503 Airspeed Limitations: General G-1 AC 27.1505 Never-Exceed Speed... G-4 AC 27.1509 Rotor Speed... G-6 AC 27.1519 Weight and Center of Gravity. G-8 AC 27.1521 Powerplant Limitations. G-9 AC 27.1521A Powerplant Limitations. G-10 AC 27.1521B Powerplant Limitations. G-10
AC 27.1523 Minimum FlightcrewG-11
AC 27.1525 Kinds of OperationsG-15
AC 27.1527 Maximum Operating Altitude G-16 AC 27.1529 Instructions for Continued Airworthiness (Maintenance Manual) . G-16 AC 27.1529A Instructions for Continued Airworthiness (Maintenance Manual) G-20
MARKINGS AND PLACARDS AC 27.1541 Marking and Placards - General. G-21 AC 27.1543 Instrument Markings: General. G-21 AC 27.1543A Instrument Markings: General G-25.1 AC 27.1545 Airspeed Indicator. G-25.6 AC 27.1545A Airspeed Indicator. G-25.7 AC 27.1547 Magnetic Direction Indicator G-25.9 AC 27.1549 Powerplant Markings.... G-25.10 AC 27.1549A Powerplant Instruments G-25.10 AC 27.1549B Powerplant Instruments G-25.10 AC 27.1549C Powerplant Instruments G-26 AC 27.1551 Oil Quantity Indicators.. G-26.1 AC 27.1553 Fuel Quantity Indicator. G-26.2 AC 27.1555 Control Markings.. G-27 AC 27.1555A Control Markings. G-28.1 AC 27.1557 Miscellaneous Markings and Placards. G-28.2 AC 27.1559 Limitations Placard G-30 AC 27.1561 Safety Equipment G-31 AC 27.1565 Tail Rotor. G-32
ROTORCRAFT FLIGHT MANUAL AND APPROVED MANUAL MATERIAL AC 27.1581 Rotorcraft Flight Manual - General G-33 AC 27.1583 Operating Limitations ... G-40 AC 27.1585 Operating Procedures.. G-42 AC 27.1585A Operating Procedures.. G-45 AC 27.1587 Performance Information G-45 AC 27.1587A Performance Information G-47 AC 27.1587B Performance Information G-48 AC 27.1589 Loading Information ..... G-48.1 Page xiv