[Code of Federal Regulations]
[Title 14, Volume 1]
[Revised as of January 1, 2006]
From the U.S. Government Printing Office via GPO Access
[CITE: 14CFR23.1]
[Page 166-181]
TITLE 14--AERONAUTICS AND SPACE
CHAPTER I--FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION
PART 23_AIRWORTHINESS STANDARDS: NORMAL, UTILITY, ACROBATIC, AND
COMMUTER CATEGORY AIRPLANES--Table of Contents
Subpart A_General
Sec. 23.1 Applicability.
Special Federal Aviation Regulation No. 23
Subpart A_General
Sec.
23.1 Applicability.
23.2 Special retroactive requirements.
23.3 Airplane categories.
Subpart B_Flight
General
23.21 Proof of compliance.
23.23 Load distribution limits.
23.25 Weight limits.
23.29 Empty weight and corresponding center of gravity.
23.31 Removable ballast.
23.33 Propeller speed and pitch limits.
Performance
23.45 General.
23.49 Stalling period.
23.51 Takeoff speeds.
23.53 Takeoff performance.
23.55 Accelerate-stop distance.
23.57 Takeoff path.
23.59 Takeoff distance and takeoff run.
23.61 Takeoff flight path.
23.63 Climb: General.
23.65 Climb: All engines operating.
23.66 Takeoff climb: One-engine inoperative.
23.67 Climb: One engine inoperative.
23.69 Enroute climb/descent.
23.71 Glide: Single-engine airplanes.
23.73 Reference landing approach speed.
23.75 Landing distance.
23.77 Balked landing.
Flight Characteristics
23.141 General.
Controllability and Maneuverability
23.143 General.
23.145 Longitudinal control.
23.147 Directional and lateral control.
23.149 Minimum control speed.
23.151 Acrobatic maneuvers.
23.153 Control during landings.
23.155 Elevator control force in maneuvers.
[[Page 167]]
23.157 Rate of roll.
Trim
23.161 Trim.
Stability
23.171 General.
23.173 Static longitudinal stability.
23.175 Demonstration of static longitudinal stability.
23.177 Static directional and lateral stability.
23.181 Dynamic stability.
Stalls
23.201 Wings level stall.
23.203 Turning flight and accelerated turning stalls.
23.207 Stall warning.
Spinning
23.221 Spinning.
Ground and Water Handling Characteristics
23.231 Longitudinal stability and control.
23.233 Directional stability and control.
23.235 Operation on unpaved surfaces.
23.237 Operation on water.
23.239 Spray characteristics.
Miscellaneous Flight Requirements
23.251 Vibration and buffeting.
23.253 High speed characteristics.
Subpart C_Structure
General
23.301 Loads.
23.302 Canard or tandem wing configurations.
23.303 Factor of safety.
23.305 Strength and deformation.
23.307 Proof of structure.
Flight Loads
23.321 General.
23.331 Symmetrical flight conditions.
23.333 Flight envelope.
23.335 Design airspeeds.
23.337 Limit maneuvering load factors.
23.341 Gust loads factors.
23.343 Design fuel loads.
23.345 High lift devices.
23.347 Unsymmetrical flight conditions.
23.349 Rolling conditions.
23.351 Yawing conditions.
23.361 Engine torque.
23.363 Side load on engine mount.
23.365 Pressurized cabin loads.
23.367 Unsymmetrical loads due to engine failure.
23.369 Rear lift truss.
23.371 Gyroscopic and aerodynamic loads.
23.373 Speed control devices.
Control Surface and System Loads
23.391 Control surface loads.
23.393 Loads parallel to hinge line.
23.395 Control system loads.
23.397 Limit control forces and torques.
23.399 Dual control system.
23.405 Secondary control system.
23.407 Trim tab effects.
23.409 Tabs.
23.415 Ground gust conditions.
Horizontal Stabilizing and Balancing Surfaces
23.421 Balancing loads.
23.423 Maneuvering loads.
23.425 Gust loads.
23.427 Unsymmetrical loads.
Vertical Surfaces
23.441 Maneuvering loads.
23.443 Gust loads.
23.445 Outboard fins or winglets.
Ailerons and Special Devices
23.455 Ailerons.
23.459 Special devices.
Ground Loads
23.471 General.
23.473 Ground load conditions and assumptions.
23.477 Landing gear arrangement.
23.479 Level landing conditions.
23.481 Tail down landing conditions.
23.483 One-wheel landing conditions.
23.485 Side load conditions.
23.493 Braked roll conditions.
23.497 Supplementary conditions for tail wheels.
23.499 Supplementary conditions for nose wheels.
23.505 Supplementary conditions for ski-planes.
23.507 Jacking loads.
23.509 Towing loads.
23.511 Ground load; unsymmetrical loads on multiple-wheel units.
Water Loads
23.521 Water load conditions.
23.523 Design weights and center of gravity positions.
23.525 Application of loads.
23.527 Hull and main float load factors.
23.529 Hull and main float landing conditions.
23.531 Hull and main float takeoff condition.
23.533 Hull and main float bottom pressures.
23.535 Auxiliary float loads.
23.537 Seawing loads.
Emergency Landing Conditions
23.561 General.
[[Page 168]]
23.562 Emergency landing dynamic conditions.
Fatigue Evaluation
23.571 Metallic pressurized cabin structures.
23.572 Metallic wing, empennage, and associated structures.
23.573 Damage tolerance and fatigue evaluation of structure.
23.574 Metallic damage tolerance and fatigue evaluation of commuter
category airplanes.
23.575 Inspections and other procedures.
Subpart D_Design and Construction
23.601 General.
23.603 Materials and workmanship.
23.605 Fabrication methods.
23.607 Fasteners.
23.609 Protection of structure.
23.611 Accessibility provisions.
23.613 Material strength properties and design values.
23.619 Special factors.
23.621 Casting factors.
23.623 Bearing factors.
23.625 Fitting factors.
23.627 Fatigue strength.
23.629 Flutter.
Wings
23.641 Proof of strength.
Control Surfaces
23.651 Proof of strength.
23.655 Installation.
23.657 Hinges.
23.659 Mass balance.
Control Systems
23.671 General.
23.672 Stability augmentation and automatic and power-operated systems.
23.673 Primary flight controls.
23.675 Stops.
23.677 Trim systems.
23.679 Control system locks.
23.681 Limit load static tests.
23.683 Operation tests.
23.685 Control system details.
23.687 Spring devices.
23.689 Cable systems.
23.691 Artificial stall barrier system.
23.693 Joints.
23.697 Wing flap controls.
23.699 Wing flap position indicator.
23.701 Flap interconnection.
23.703 Takeoff warning system.
Landing Gear
23.721 General.
23.723 Shock absorption tests.
23.725 Limit drop tests.
23.726 Ground load dynamic tests.
23.727 Reserve energy absorption drop test.
23.729 Landing gear extension and retraction system.
23.731 Wheels.
23.733 Tires.
23.735 Brakes.
23.737 Skis.
23.745 Nose/tail wheel steering.
Floats and Hulls
23.751 Main float buoyancy.
23.753 Main float design.
23.755 Hulls.
23.757 Auxiliary floats.
Personnel and Cargo Accommodations
23.771 Pilot compartment.
23.773 Pilot compartment view.
23.775 Windshields and windows.
23.777 Cockpit controls.
23.779 Motion and effect of cockpit controls.
23.781 Cockpit control knob shape.
23.783 Doors.
23.785 Seats, berths, litters, safety belts, and shoulder harnesses.
23.787 Baggage and cargo compartments.
23.791 Passenger information signs.
23.803 Emergency evacuation.
23.805 Flightcrew emergency exits.
23.807 Emergency exits.
23.811 Emergency exit marking.
23.812 Emergency lighting.
23.813 Emergency exit access.
23.815 Width of aisle.
23.831 Ventilation.
Pressurization
23.841 Pressurized cabins.
23.843 Pressurization tests.
Fire Protection
23.851 Fire extinguishers.
23.853 Passenger and crew compartment interiors.
23.855 Cargo and baggage compartment fire protection.
23.859 Combustion heater fire protection.
23.863 Flammable fluid fire protection.
23.865 Fire protection of flight controls, engine mounts, and other
flight structure.
Electrical Bonding and Lightning Protection
23.867 Electrical bonding and protection against lightning and static
electricity.
Miscellaneous
23.871 Leveling means.
Subpart E_Powerplant
General
23.901 Installation.
23.903 Engines.
23.904 Automatic power reserve system.
23.905 Propellers.
[[Page 169]]
23.907 Propeller vibration.
23.909 Turbocharger systems.
23.925 Propeller clearance.
23.929 Engine installation ice protection.
23.933 Reversing systems.
23.934 Turbojet and turbofan engine thrust reverser systems tests.
23.937 Turbopropeller-drag limiting systems.
23.939 Powerplant operating characteristics.
23.943 Negative acceleration.
Fuel System
23.951 General.
23.953 Fuel system independence.
23.954 Fuel system lightning protection.
23.955 Fuel flow.
23.957 Flow between interconnected tanks.
23.959 Unusable fuel supply.
23.961 Fuel system hot weather operation.
23.963 Fuel tanks: General.
23.965 Fuel tank tests.
23.967 Fuel tank installation.
23.969 Fuel tank expansion space.
23.971 Fuel tank sump.
23.973 Fuel tank filler connection.
23.975 Fuel tank vents and carburetor vapor vents.
23.977 Fuel tank outlet.
23.979 Pressure fueling systems.
Fuel System Components
23.991 Fuel pumps.
23.993 Fuel system lines and fittings.
23.994 Fuel system components.
23.995 Fuel valves and controls.
23.997 Fuel strainer or filter.
23.999 Fuel system drains.
23.1001 Fuel jettisoning system.
Oil System
23.1011 General.
23.1013 Oil tanks.
23.1015 Oil tank tests.
23.1017 Oil lines and fittings.
23.1019 Oil strainer or filter.
23.1021 Oil system drains.
23.1023 Oil radiators.
23.1027 Propeller feathering system.
Cooling
23.1041 General.
23.1043 Cooling tests.
23.1045 Cooling test procedures for turbine engine powered airplanes.
23.1047 Cooling test procedures for reciprocating engine powered
airplanes.
Liquid Cooling
23.1061 Installation.
23.1063 Coolant tank tests.
Induction System
23.1091 Air induction system.
23.1093 Induction system icing protection.
23.1095 Carburetor deicing fluid flow rate.
23.1097 Carburetor deicing fluid system capacity.
23.1099 Carburetor deicing fluid system detail design.
23.1101 Induction air preheater design.
23.1103 Induction system ducts.
23.1105 Induction system screens.
23.1107 Induction system filters.
23.1109 Turbocharger bleed air system.
23.1111 Turbine engine bleed air system.
Exhaust System
23.1121 General.
23.1123 Exhaust system.
23.1125 Exhaust heat exchangers.
Powerplant Controls and Accessories
23.1141 Powerplant controls: General.
23.1142 Auxiliary power unit controls.
23.1143 Engine controls.
23.1145 Ignition switches.
23.1147 Mixture controls.
23.1149 Propeller speed and pitch controls.
23.1153 Propeller feathering controls.
23.1155 Turbine engine reverse thrust and propeller pitch settings below
the flight regime.
23.1157 Carburetor air temperature controls.
23.1163 Powerplant accessories.
23.1165 Engine ignition systems.
Powerplant Fire Protection
23.1181 Designated fire zones; regions included.
23.1182 Nacelle areas behind firewalls.
23.1183 Lines, fittings, and components.
23.1189 Shutoff means.
23.1191 Firewalls.
23.1192 Engine accessory compartment diaphragm.
23.1193 Cowling and nacelle.
23.1195 Fire extinguishing systems.
23.1197 Fire extinguishing agents.
23.1199 Extinguishing agent containers.
23.1201 Fire extinguishing systems materials.
23.1203 Fire detector system.
Subpart F_Equipment
General
23.1301 Function and installation.
23.1303 Flight and navigation instruments.
23.1305 Powerplant instruments.
23.1307 Miscellaneous equipment.
23.1309 Equipment, systems, and installations.
Instruments: Installation
23.1311 Electronic display instrument systems.
23.1321 Arrangement and visibility.
23.1322 Warning, caution, and advisory lights.
23.1323 Airspeed indicating system.
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23.1325 Static pressure system.
23.1326 Pitot heat indication systems.
23.1327 Magnetic direction indicator.
23.1329 Automatic pilot system.
23.1331 Instruments using a power source.
23.1335 Flight director systems.
23.1337 Powerplant instruments installation.
Electrical Systems and Equipment
23.1351 General.
23.1353 Storage battery design and installation.
23.1357 Circuit protective devices.
23.1359 Electrical system fire protection.
23.1361 Master switch arrangement.
23.1365 Electric cables and equipment.
23.1367 Switches.
Lights
23.1381 Instrument lights.
23.1383 Taxi and landing lights.
23.1385 Position light system installation.
23.1387 Position light system dihedral angles.
23.1389 Position light distribution and intensities.
23.1391 Minimum intensities in the horizontal plane of position lights.
23.1393 Minimum intensities in any vertical plane of position lights.
23.1395 Maximum intensities in overlapping beams of position lights.
23.1397 Color specifications.
23.1399 Riding light.
23.1401 Anticollision light system.
Safety Equipment
23.1411 General.
23.1415 Ditching equipment.
23.1416 Pneumatic de-icer boot system.
23.1419 Ice protection.
Miscellaneous Equipment
23.1431 Electronic equipment.
23.1435 Hydraulic systems.
23.1437 Accessories for multiengine airplanes.
23.1438 Pressurization and pneumatic systems.
23.1441 Oxygen equipment and supply.
23.1443 Minimum mass flow of supplemental oxygen.
23.1445 Oxygen distribution system.
23.1447 Equipment standards for oxygen dispensing units.
23.1449 Means for determining use of oxygen.
23.1450 Chemical oxygen generators.
23.1451 Fire protection for oxygen equipment.
23.1453 Protection of oxygen equipment from rupture.
23.1457 Cockpit voice recorders.
23.1459 Flight recorders.
23.1461 Equipment containing high energy rotors.
Subpart G_Operating Limitations and Information
23.1501 General.
23.1505 Airspeed limitations.
23.1507 Operating maneuvering speed.
23.1511 Flap extended speed.
23.1513 Minimum control speed.
23.1519 Weight and center of gravity.
23.1521 Powerplant limitations.
23.1522 Auxiliary power unit limitations.
23.1523 Minimum flight crew.
23.1524 Maximum passenger seating configuration.
23.1525 Kinds of operation.
23.1527 Maximum operating altitude.
23.1529 Instructions for Continued Airworthiness.
Markings and Placards
23.1541 General.
23.1543 Instrument markings: General.
23.1545 Airspeed indicator.
23.1547 Magnetic direction indicator.
23.1549 Powerplant and auxiliary power unit instruments.
23.1551 Oil quantity indicator.
23.1553 Fuel quantity indicator.
23.1555 Control markings.
23.1557 Miscellaneous markings and placards.
23.1559 Operating limitations placard.
23.1561 Safety equipment.
23.1563 Airspeed placards.
23.1567 Flight maneuver placard.
Airplane Flight Manual and Approved Manual Material
23.1581 General.
23.1583 Operating limitations.
23.1585 Operating procedures.
23.1587 Performance information.
23.1589 Loading information.
Appendix A to Part 23--Simplified Design Load Criteria
Appendix B to Part 23 [Reserved]
Appendix C to Part 23--Basic Landing Conditions
Appendix D to Part 23--Wheel Spin-Up and Spring-Back Loads
Appendix E to Part 23 [Reserved]
Appendix F to Part 23--Test Procedure
Appendix G to Part 23--Instructions for Continued Airworthiness
Appendix H to Part 23--Installation of An Automatic Power Reserve (APR)
System
Appendix I to Part 23--Seaplane Loads
Authority: 49 U.S.C. 106(g), 40113, 44701-44702, 44704.
Source: Docket No. 4080, 29 FR 17955, Dec. 18. 1964; 30 FR 258, Jan.
9, 1965, unless otherwise noted.
[[Page 171]]
Special Federal Aviation Regulation No. 23
1. Applicability. An applicant is entitled to a type certificate in
the normal category for a reciprocating or turbopropeller multiengine
powered small airplane that is to be certificated to carry more than 10
occupants and that is intended for use in operations under Part 135 of
the Federal Aviation Regulations if he shows compliance with the
applicable requirements of Part 23 of the Federal Aviation Regulations,
as supplemented or modified by the additional airworthiness requirements
of this regulation.
2. References. Unless otherwise provided, all references in this
regulation to specific sections of Part 23 of the Federal Aviation
Regulations are those sections of Part 23 in effect on March 30, 1967.
Flight Requirements
3. General. Compliance must be shown with the applicable
requirements of Subpart B of Part 23 of the Federal Aviation Regulations
in effect on March 30, 1967, as supplemented or modified in sections 4
through 10 of this regulation.
Performance
4. General. (a) Unless otherwise prescribed in this regulation,
compliance with each applicable performance requirement in sections 4
through 7 of this regulation must be shown for ambient atmospheric
conditions and still air.
(b) The performance must correspond to the propulsive thrust
available under the particular ambient atmospheric conditions and the
particular flight condition. The available propulsive thrust must
correspond to engine power or thrust, not exceeding the approved power
or thrust less--
(1) Installation losses; and
(2) The power or equivalent thrust absorbed by the accessories and
services appropriate to the particular ambient atmospheric conditions
and the particular flight condition.
(c) Unless otherwise prescribed in this regulation, the applicant
must select the take-off, en route, and landing configurations for the
airplane.
(d) The airplane configuration may vary with weight, altitude, and
temperature, to the extent they are compatible with the operating
procedures required by paragraph (e) of this section.
(e) Unless otherwise prescribed in this regulation, in determining
the critical engine inoperative takeoff performance, the accelerate-stop
distance, takeoff distance, changes in the airplane's configuration,
speed, power, and thrust, must be made in accordance with procedures
established by the applicant for operation in service.
(f) Procedures for the execution of balked landings must be
established by the applicant and included in the Airplane Flight Manual.
(g) The procedures established under paragraphs (e) and (f) of this
section must--
(1) Be able to be consistently executed in service by a crew of
average skill;
(2) Use methods or devices that are safe and reliable; and
(3) Include allowance for any time delays, in the execution of the
procedures, that may reasonably be expected in service.
5. Takeoff--(a) General. The takeoff speeds described in paragraph
(b), the accelerate-stop distance described in paragraph (c), and the
takeoff distance described in paragraph (d), must be determined for--
(1) Each weight, altitude, and ambient temperature within the
operational limits selected by the applicant;
(2) The selected configuration for takeoff;
(3) The center of gravity in the most unfavorable position;
(4) The operating engine within approved operating limitation; and
(5) Takeoff data based on smooth, dry, hard-surface runway.
(b) Takeoff speeds. (1) The decision speed V1 is the
calibrated airspeed on the ground at which, as a result of engine
failure or other reasons, the pilot is assumed to have made a decision
to continue or discontinue the takeoff. The speed V1 must be
selected by the applicant but may not be less than--
(i) 1.10 Vs1;
(ii) 1.10 VMC;
(iii) A speed that permits acceleration to V1 and stop in
accordance with paragraph (c) allowing credit for an overrun distance
equal to that required to stop the airplane from a ground speed of 35
knots utilizing maximum braking; or
(iv) A speed at which the airplane can be rotated for takeoff and
shown to be adequate to safely continue the takeoff, using normal
piloting skill, when the critical engine is suddenly made inoperative.
(2) Other essential takeoff speeds necessary for safe operation of
the airplane must be determined and shown in the Airplane Flight Manual.
(c) Accelerate-stop distance. (1) The accelerate-stop distance is
the sum of the distances necessary to--
(i) Accelerate the airplane from a standing start to V1;
and
(ii) Decelerate the airplane from V1 to a speed not greater than 35
knots, assuming that in the case of engine failure, failure of the
critical engine is recognized by the pilot at the speed V1.
The landing gear must remain in the extended position and maximum
braking may be utilized during deceleration.
[[Page 172]]
(2) Means other than wheel brakes may be used to determine the
accelerate-stop distance if that means is available with the critical
engine inoperative and--
(i) Is safe and reliable;
(ii) Is used so that consistent results can be expected under normal
operating conditions; and
(iii) Is such that exceptional skill is not required to control the
airplane.
(d) All engines operating takeoff distance. The all engine operating
takeoff distance is the horizontal distance required to takeoff and
climb to a height of 50 feet above the takeoff surface according to
procedures in FAR 23.51(a).
(e) One-engine-inoperative takeoff. The maximum weight must be
determined for each altitude and temperature within the operational
limits established for the airplane, at which the airplane has takeoff
capability after failure of the critical engine at or above
V1 determined in accordance with paragraph (b) of this
section. This capability may be established--
(1) By demonstrating a measurably positive rate of climb with the
airplane in the takeoff configuration, landing gear extended; or
(2) By demonstrating the capability of maintaining flight after
engine failure utilizing procedures prescribed by the applicant.
6. Climb--(a) Landing climb: All-engines-operating. The maximum
weight must be determined with the airplane in the landing
configuration, for each altitude, and ambient temperature within the
operational limits established for the airplane and with the most
unfavorable center of gravity and out-of-ground effect in free air, at
which the steady gradient of climb will not be less than 3.3 percent,
with:
(1) The engines at the power that is available 8 seconds after
initiation of movement of the power or thrust controls from the mimimum
flight idle to the takeoff position.
(2) A climb speed not greater than the approach speed established
under section 7 of this regulation and not less than the greater of
1.05MC or 1.10VS1.
(b) En route climb, one-engine-inoperative. (1) the maximum weight
must be determined with the airplane in the en route configuration, the
critical engine inoperative, the remaining engine at not more than
maximum continuous power or thrust, and the most unfavorable center of
gravity, at which the gradient at climb will be not less than--
(i) 1.2 percent (or a gradient equivalent to 0.20 Vso2, if greater)
at 5,000 feet and an ambient temperature of 41 [deg]F. or
(ii) 0.6 percent (or a gradient equivalent to 0.01 Vso2, if greater)
at 5,000 feet and ambient temperature of 81 [deg]F.
(2) The minimum climb gradient specified in subdivisions (i) and
(ii) of subparagraph (1) of this paragraph must vary linearly between 41
[deg]F. and 81 [deg]F. and must change at the same rate up to the
maximum operational temperature approved for the airplane.
7. Landing. The landing distance must be determined for standard
atmosphere at each weight and altitude in accordance with FAR 23.75(a),
except that instead of the gliding approach specified in FAR
23.75(a)(1), the landing may be preceded by a steady approach down to
the 50-foot height at a gradient of descent not greater than 5.2 percent
(3[deg]) at a calibrated airspeed not less than 1.3s1.
Trim
8. Trim--(a) Lateral and directional trim. The airplane must
maintain lateral and directional trim in level flight at a speed of Vh
or VMO/MMO, whichever is lower, with landing gear and wing flaps
retracted.
(b) Longitudinal trim. The airplane must maintain longitudinal trim
during the following conditions, except that it need not maintain trim
at a speed greater than VMO/MMO:
(1) In the approach conditions specified in FAR 23.161(c)(3) through
(5), except that instead of the speeds specified therein, trim must be
maintained with a stick force of not more than 10 pounds down to a speed
used in showing compliance with section 7 of this regulation or 1.4 Vs1
whichever is lower.
(2) In level flight at any speed from VH or VMO/MMO, whichever is
lower, to either Vx or 1.4 Vs1, with the landing gear and
wing flaps retracted.
Stability
9. Static longitudinal stability. (a) In showing compliance with the
provisions of FAR 23.175(b) and with paragraph (b) of this section, the
airspeed must return to within 7\1/2\ percent of
the trim speed.
(b) Cruise stability. The stick force curve must have a stable slope
for a speed range of 50 knots from the trim speed
except that the speeds need not exceed VFC/MFC or be less than 1.4
Vs1. This speed range will be considered to begin at the
outer extremes of the friction band and the stick force may not exceed
50 pounds with--
(i) Landing gear retracted;
(ii) Wing flaps retracted;
(iii) The maximum cruising power as selected by the applicant as an
operating limitation for turbine engines or 75 percent of maximum
continuous power for reciprocating engines except that the power need
not exceed that required at VMO/MMO:
(iv) Maximum takeoff weight; and
(v) The airplane trimmed for level flight with the power specified
in subparagraph (iii) of this paragraph.
VFC/MFC may not be less than a speed midway between VMO/MMO and VDF/
MDF, except that, for altitudes where Mach number is the
[[Page 173]]
limiting factor, MFC need not exceed the Mach number at which effective
speed warning occurs.
(c) Climb stability. For turbopropeller powered airplanes only. In
showing compliance with FAR 23.175(a), an applicant must in lieu of the
power specified in FAR 23.175(a)(4), use the maximum power or thrust
selected by the applicant as an operating limitation for use during
climb at the best rate of climb speed except that the speed need not be
less than 1.4 Vs1.
Stalls
10. Stall warning. If artificial stall warning is required to comply
with the requirements of FAR 23.207, the warning device must give
clearly distinguishable indications under expected conditions of flight.
The use of a visual warning device that requires the attention of the
crew within the cockpit is not acceptable by itself.
Control Systems
11. Electric trim tabs. The airplane must meet the requirements of
FAR 23.677 and in addition it must be shown that the airplane is safely
controllable and that a pilot can perform all the maneuvers and
operations necessary to effect a safe landing following any probable
electric trim tab runaway which might be reasonably expected in service
allowing for appropriate time delay after pilot recognition of the
runaway. This demonstration must be conducted at the critical airplane
weights and center of gravity positions.
Instruments: Installation
12. Arrangement and visibility. Each instrument must meet the
requirements of FAR 23.1321 and in addition--
(a) Each flight, navigation, and powerplant instrument for use by
any pilot must be plainly visible to him from his station with the
minimum practicable deviation from his normal position and line of
vision when he is looking forward along the flight path.
(b) The flight instruments required by FAR 23.1303 and by the
applicable operating rules must be grouped on the instrument panel and
centered as nearly as practicable about the vertical plane of each
pilot's forward vision. In addition--
(1) The instrument that most effectively indicates the attitude must
be on the panel in the top center position;
(2) The instrument that most effectively indicates airspeed must be
adjacent to and directly to the left of the instrument in the top center
position;
(3) The instrument that most effectively indicates altitude must be
adjacent to and directly to the right of the instrument in the top
center position; and
(4) The instrument that most effectively indicates direction of
flight must be adjacent to and directly below the instrument in the top
center position.
13. Airspeed indicating system. Each airspeed indicating system must
meet the requirements of FAR 23.1323 and in addition--
(a) Airspeed indicating instruments must be of an approved type and
must be calibrated to indicate true airspeed at sea level in the
standard atmosphere with a mimimum practicable instrument calibration
error when the corresponding pilot and static pressures are supplied to
the instruments.
(b) The airspeed indicating system must be calibrated to determine
the system error, i.e., the relation between IAS and CAS, in flight and
during the accelerate takeoff ground run. The ground run calibration
must be obtained between 0.8 of the mimimum value of V1 and
1.2 times the maximum value of V1, considering the approved
ranges of altitude and weight. The ground run calibration will be
determined assuming an engine failure at the mimimum value of
V1.
(c) The airspeed error of the installation excluding the instrument
calibration error, must not exceed 3 percent or 5 knots whichever is
greater, throughout the speed range from VMO to 1.3S1 with
flaps retracted and from 1.3 VSO to VFE with flaps in the
landing position.
(d) Information showing the relationship between IAS and CAS must be
shown in the Airplane Flight Manual.
14. Static air vent system. The static air vent system must meet the
requirements of FAR 23.1325. The altimeter system calibration must be
determined and shown in the Airplane Flight Manual.
Operating Limitations and Information
15. Maximum operating limit speed VMO/MMO. Instead of establishing
operating limitations based on VME and VNO, the applicant must establish
a maximum operating limit speed VMO/MMO in accordance with the
following:
(a) The maximum operating limit speed must not exceed the design
cruising speed Vc and must be sufficiently below VD/MD or VDF/MDF to
make it highly improbable that the latter speeds will be inadvertently
exceeded in flight.
(b) The speed Vmo must not exceed 0.8 VD/MD or 0.8 VDF/MDF unless
flight demonstrations involving upsets as specified by the Administrator
indicates a lower speed margin will not result in speeds exceeding VD/MD
or VDF. Atmospheric variations, horizontal gusts, and equipment errors,
and airframe production variations will be taken into account.
16. Minimum flight crew. In addition to meeting the requirements of
FAR 23.1523, the
[[Page 174]]
applicant must establish the minimum number and type of qualified flight
crew personnel sufficient for safe operation of the airplane
considering--
(a) Each kind of operation for which the applicant desires approval;
(b) The workload on each crewmember considering the following:
(1) Flight path control.
(2) Collision avoidance.
(3) Navigation.
(4) Communications.
(5) Operation and monitoring of all essential aircraft systems.
(6) Command decisions; and
(c) The accessibility and ease of operation of necessary controls by
the appropriate crewmember during all normal and emergency operations
when at his flight station.
17. Airspeed indicator. The airspeed indicator must meet the
requirements of FAR 23.1545 except that, the airspeed notations and
markings in terms of VNO and VNE must be replaced by the VMO/MMO
notations. The airspeed indicator markings must be easily read and
understood by the pilot. A placard adjacent to the airspeed indicator is
an acceptable means of showing compliance with the requirements of FAR
23.1545(c).
Airplane Flight Manual
18. General. The Airplane Flight Manual must be prepared in
accordance with the requirements of FARs 23.1583 and 23.1587, and in
addition the operating limitations and performance information set forth
in sections 19 and 20 must be included.
19. Operating limitations. The Airplane Flight Manual must include
the following limitations--
(a) Airspeed limitations. (1) The maximum operating limit speed VMO/
MMO and a statement that this speed limit may not be deliberately
exceeded in any regime of flight (climb, cruise, or descent) unless a
higher speed is authorized for flight test or pilot training;
(2) If an airspeed limitation is based upon compressibility effects,
a statement to this effect and information as to any symptoms, the
probable behavior of the airplane, and the recommended recovery
procedures; and
(3) The airspeed limits, shown in terms of VMO/MMO instead of VNO
and VNE.
(b) Takeoff weight limitations. The maximum takeoff weight for each
airport elevation, ambient temperature, and available takeoff runway
length within the range selected by the applicant. This weight may not
exceed the weight at which:
(1) The all-engine operating takeoff distance determined in
accordance with section 5(d) or the accelerate-stop distance determined
in accordance with section 5(c), which ever is greater, is equal to the
available runway length;
(2) The airplane complies with the one-engine-inoperative takeoff
requirements specified in section 5(e); and
(3) The airplane complies with the one-engine-inoperative en route
climb requirements specified in section 6(b), assuming that a standard
temperature lapse rate exists from the airport elevation to the altitude
of 5,000 feet, except that the weight may not exceed that corresponding
to a temperature of 41 [deg]F at 5,000 feet.
20. Performance information. The Airplane Flight Manual must contain
the performance information determined in accordance with the provisions
of the performance requirements of this regulation. The information must
include the following:
(a) Sufficient information so that the take-off weight limits
specified in section 19(b) can be determined for all temperatures and
altitudes within the operation limitations selected by the applicant.
(b) The conditions under which the performance information was
obtained, including the airspeed at the 50-foot height used to determine
landing distances.
(c) The performance information (determined by extrapolation and
computed for the range of weights between the maximum landing and
takeoff weights) for--
(1) Climb in the landing configuration; and
(2) Landing distance.
(d) Procedure established under section 4 of this regulation related
to the limitations and information required by this section in the form
of guidance material including any relevant limitations or information.
(e) An explanation of significant or unusual flight or ground
handling characteristics of the airplane.
(f) Airspeeds, as indicated airspeeds, corresponding to those
determined for takeoff in accordance with section 5(b).
21. Maximum operating altitudes. The maximum operating altitude to
which operation is permitted, as limited by flight, structural,
powerplant, functional, or equipment characteristics, must be specified
in the Airplane Flight Manual.
22. Stowage provision for Airplane Flight Manual. Provision must be
made for stowing the Airplane Flight Manual in a suitable fixed
container which is readily accessible to the pilot.
23. Operating procedures. Procedures for restarting turbine engines
in flight (including the effects of altitude) must be set forth in the
Airplane Flight Manual.
Airframe Requirements
flight loads
24. Engine torque. (a) Each turbopropeller engine mount and its
supporting structure must be designed for the torque effects of--
(1) The conditions set forth in FAR 23.361(a).
[[Page 175]]
(2) The limit engine torque corresponding to takeoff power and
propeller speed, multiplied by a factor accounting for propeller control
system malfunction, including quick feathering action, simultaneously
with 1 g level flight loads. In the absence of a rational analysis, a
factor of 1.6 must be used.
(b) The limit torque is obtained by multiplying the mean torque by a
factor of 1.25.
25. Turbine engine gyroscopic loads. Each turbopropeller engine
mount and its supporting structure must be designed for the gyroscopic
loads that result, with the engines at maximum continuous r.p.m., under
either--
(a) The conditions prescribed in FARs 23.351 and 23.423; or
(b) All possible combinations of the following:
(1) A yaw velocity of 2.5 radius per second.
(2) A pitch velocity of 1.0 radians per second.
(3) A normal load factor of 2.5.
(4) Maximum continuous thrust.
26. Unsymmetrical loads due to engine failure. (a) Turbopropeller
powered airplanes must be designed for the unsymmetrical loads resulting
from the failure of the critical engine including the following
conditions in combination with a single malfunction of the propeller
drag limiting system, considering the probable pilot corrective action
on the flight controls.
(1) At speeds between VMC and VD, the loads resulting from power
failure because of fuel flow interruption are considered to be limit
loads.
(2) At speeds between VMC and VC, the loads resulting from the
disconnection of the engine compressor from the turbine or from loss of
the turbine blades are considered to be ultimate loads.
(3) The time history of the thrust decay and drag buildup occurring
as a result of the prescribed engine failures must be substantiated by
test or other data applicable to the particular engine-propeller
combination.
(4) The timing and magnitude of the probable pilot corrective action
must be conservatively estimated, considering the characteristics of the
particular engine-propeller-airplane combination.
(b) Pilot corrective action may be assumed to be initiated at the
time maximum yawing velocity is reached, but not earlier than two
seconds after the engine failure. The magnitude of the corrective action
may be based on the control forces specified in FAR 23.397 except that
lower forces may be assumed where it is shown by analysis or test that
these forces can control the yaw and roll resulting from the prescribed
engine failure conditions.
Ground Loads
27. Dual wheel landing gear units. Each dual wheel landing gear unit
and its supporting structure must be shown to comply with the following:
(a) Pivoting. The airplane must be assumed to pivot about one side
of the main gear with the brakes on that side locked. The limit vertical
load factor must be 1.0 and the coefficient of friction 0.8. This
condition need apply only to the main gear and its supporting structure.
(b) Unequal tire inflation. A 60-40 percent distribution of the
loads established in accordance with FAR 23.471 through FAR 23.483 must
be applied to the dual wheels.
(c) Flat tire. (1) Sixty percent of the loads specified in FAR
23.471 through FAR 23.483 must be applied to either wheel in a unit.
(2) Sixty percent of the limit drag and side loads and 100 percent
of the limit vertical load established in accordance with FARs 23.493
and 23.485 must be applied to either wheel in a unit except that the
vertical load need not exceed the maximum vertical load in paragraph
(c)(1) of this section.
Fatigue Evaluation
28. Fatigue evaluation of wing and associated structure. Unless it
is shown that the structure, operating stress levels, materials, and
expected use are comparable from a fatigue standpoint to a similar
design which has had substantial satisfactory service experience, the
strength, detail design, and the fabrication of those parts of the wing,
wing carrythrough, and attaching structure whose failure would be
catastrophic must be evaluated under either--
(a) A fatigue strength investigation in which the structure is shown
by analysis, tests, or both to be able to withstand the repeated loads
of variable magnitude expected in service; or
(b) A fail-safe strength investigation in which it is shown by
analysis, tests, or both that catastrophic failure of the structure is
not probable after fatigue, or obvious partial failure, of a principal
structural element, and that the remaining structure is able to
withstand a static ultimate load factor of 75 percent of the critical
limit load factor at Vc. These loads must be multiplied by a factor of
1.15 unless the dynamic effects of failure under static load are
otherwise considered.
Design and Construction
29. Flutter. For Multiengine turbopropeller powered airplanes, a
dynamic evaluation must be made and must include--
(a) The significant elastic, inertia, and aerodynamic forces
associated with the rotations and displacements of the plane of the
propeller; and
(b) Engine-propeller-nacelle stiffness and damping variations
appropriate to the particular configuration.
[[Page 176]]
Landing Gear
30. Flap operated landing gear warning device. Airplanes having
retractable landing gear and wing flaps must be equipped with a warning
device that functions continuously when the wing flaps are extended to a
flap position that activates the warning device to give adequate warning
before landing, using normal landing procedures, if the landing gear is
not fully extended and locked. There may not be a manual shut off for
this warning device. The flap position sensing unit may be installed at
any suitable location. The system for this device may use any part of
the system (including the aural warning device) provided for other
landing gear warning devices.
Personnel and Cargo Accommodations
31. Cargo and baggage compartments. Cargo and baggage compartments
must be designed to meet the requirements of FAR 23.787 (a) and (b), and
in addition means must be provided to protect passengers from injury by
the contents of any cargo or baggage compartment when the ultimate
forward inertia force is 9g.
32. Doors and exits. The airplane must meet the requirements of FAR
23.783 and FAR 23.807 (a)(3), (b), and (c), and in addition:
(a) There must be a means to lock and safeguard each external door
and exit against opening in flight either inadvertently by persons, or
as a result of mechanical failure. Each external door must be operable
from both the inside and the outside.
(b) There must be means for direct visual inspection of the locking
mechanism by crewmembers to determine whether external doors and exits,
for which the initial opening movement is outward, are fully locked. In
addition, there must be a visual means to signal to crewmembers when
normally used external doors are closed and fully locked.
(c) The passenger entrance door must qualify as a floor level
emergency exit. Each additional required emergency exit except floor
level exits must be located over the wing or must be provided with
acceptable means to assist the occupants in descending to the ground. In
addition to the passenger entrance door:
(1) For a total seating capacity of 15 or less, an emergency exit as
defined in FAR 23.807(b) is required on each side of the cabin.
(2) For a total seating capacity of 16 through 23, three emergency
exits as defined in 23.807(b) are required with one on the same side as
the door and two on the side opposite the door.
(d) An evacuation demonstration must be conducted utilizing the
maximum number of occupants for which certification is desired. It must
be conducted under simulated night conditions utilizing only the
emergency exits on the most critical side of the aircraft. The
participants must be representative of average airline passengers with
no prior practice or rehearsal for the demonstration. Evacuation must be
completed within 90 seconds.
(e) Each emergency exit must be marked with the word ``Exit'' by a
sign which has white letters 1 inch high on a red background 2 inches
high, be self-illuminated or independently internally electrically
illuminated, and have a minimum luminescence (brightness) of at least
160 microlamberts. The colors may be reversed if the passenger
compartment illumination is essentially the same.
(f) Access to window type emergency exits must not be obstructed by
seats or seat backs.
(g) The width of the main passenger aisle at any point between seats
must equal or exceed the values in the following table.
------------------------------------------------------------------------
Minimum main passenger aisle width
---------------------------------------
Total seating capacity Less than 25 25 inches and more
inches from floor from floor
------------------------------------------------------------------------
10 through 23................... 9 inches.......... 15 inches.
------------------------------------------------------------------------
Miscellaneous
33. Lightning strike protection. Parts that are electrically
insulated from the basic airframe must be connected to it through
lightning arrestors unless a lightning strike on the insulated part--
(a) Is improbable because of shielding by other parts; or
(b) Is not hazardous.
34. Ice protection. If certification with ice protection provisions
is desired, compliance with the following requirements must be shown:
(a) The recommended procedures for the use of the ice protection
equipment must be set forth in the Airplane Flight Manual.
(b) An analysis must be performed to establish, on the basis of the
airplane's operational needs, the adequacy of the ice protection system
for the various components of the airplane. In addition, tests of the
ice protection system must be conducted to demonstrate that the airplane
is capable of operating safely in continuous maximum and intermittent
maximum icing conditions as described in FAR 25, appendix C.
(c) Compliance with all or portions of this section may be
accomplished by reference, where applicable because of similarity of the
designs, to analysis and tests performed by the applicant for a type
certificated model.
35. Maintenance information. The applicant must make available to
the owner at the time of delivery of the airplane the information he
considers essential for the proper maintenance of the airplane. That
information must include the following:
[[Page 177]]
(a) Description of systems, including electrical, hydraulic, and
fuel controls.
(b) Lubrication instructions setting forth the frequency and the
lubricants and fluids which are to be used in the various systems.
(c) Pressures and electrical loads applicable to the various
systems.
(d) Tolerances and adjustments necessary for proper functioning.
(e) Methods of leveling, raising, and towing.
(f) Methods of balancing control surfaces.
(g) Identification of primary and secondary structures.
(h) Frequency and extent of inspections necessary to the proper
operation of the airplane.
(i) Special repair methods applicable to the airplane.
(j) Special inspection techniques, including those that require X-
ray, ultrasonic, and magnetic particle inspection.
(k) List of special tools.
Propulsion
general
36. Vibration characteristics. For turbopropeller powered airplanes,
the engine installation must not result in vibration characteristics of
the engine exceeding those established during the type certification of
the engine.
37. In-flight restarting of engine. If the engine on turbopropeller
powered airplanes cannot be restarted at the maximum cruise altitude, a
determination must be made of the altitude below which restarts can be
consistently accomplished. Restart information must be provided in the
Airplane Flight Manual.
38. Engines--(a) For turbopropeller powered airplanes. The engine
installation must comply with the following requirements:
(1) Engine isolation. The powerplants must be arranged and isolated
from each other to allow operation, in at least one configuration, so
that the failure or malfunction of any engine, or of any system that can
affect the engine, will not--
(i) Prevent the continued safe operation of the remaining engines;
or
(ii) Require immediate action by any crewmember for continued safe
operation.
(2) Control of engine rotation. There must be a means to
individually stop and restart the rotation of any engine in flight
except that engine rotation need not be stopped if continued rotation
could not jeopardize the safety of the airplane. Each component of the
stopping and restarting system on the engine side of the firewall, and
that might be exposed to fire, must be at least fire resistant. If
hydraulic propeller feathering systems are used for this purpose, the
feathering lines must be at least fire resistant under the operating
conditions that may be expected to exist during feathering.
(3) Engine speed and gas temperature control devices. The powerplant
systems associated with engine control devices, systems, and
instrumentation must provide reasonable assurance that those engine
operating limitations that adversely affect turbine rotor structural
integrity will not be exceeded in service.
(b) For reciprocating-engine powered airplanes. To provide engine
isolation, the powerplants must be arranged and isolated from each other
to allow operation, in at least one configuration, so that the failure
or malfunction of any engine, or of any system that can affect that
engine, will not--
(1) Prevent the continued safe operation of the remaining engines;
or
(2) Require immediate action by any crewmember for continued safe
operation.
39. Turbopropeller reversing systems. (a) Turbopropeller reversing
systems intended for ground operation must be designed so that no single
failure or malfunction of the system will result in unwanted reverse
thrust under any expected operating condition. Failure of structural
elements need not be considered if the probability of this kind of
failure is extremely remote.
(b) Turbopropeller reversing systems intended for in-flight use must
be designed so that no unsafe condition will result during normal
operation of the system, or from any failure (or reasonably likely
combination of failures) of the reversing system, under any anticipated
condition of operation of the airplane. Failure of structural elements
need not be considered if the probability of this kind of failure is
extremely remote.
(c) Compliance with this section may be shown by failure analysis,
testing, or both for propeller systems that allow propeller blades to
move from the flight low-pitch position to a position that is
substantially less than that at the normal flight low-pitch stop
position. The analysis may include or be supported by the analysis made
to show compliance with the type certification of the propeller and
associated installation components. Credit will be given for pertinent
analysis and testing completed by the engine and propeller
manufacturers.
40. Turbopropeller drag-limiting systems. Turbopropeller drag-
limiting systems must be designed so that no single failure or
malfunction of any of the systems during normal or emergency operation
results in propeller drag in excess of that for which the airplane was
designed. Failure of structural elements of the drag-limiting systems
need not be considered if the probability of this kind of failure is
extremely remote.
41. Turbine engine powerplant operating characteristics. For
turbopropeller powered airplanes, the turbine engine powerplant
operating characteristics must be investigated
[[Page 178]]
in flight to determine that no adverse characteristics (such as stall,
surge, or flameout) are present to a hazardous degree, during normal and
emergency operation within the range of operating limitations of the
airplane and of the engine.
42. Fuel flow. (a) For turbopropeller powered airplanes--
(1) The fuel system must provide for continuous supply of fuel to
the engines for normal operation without interruption due to depletion
of fuel in any tank other than the main tank; and
(2) The fuel flow rate for turbopropeller engine fuel pump systems
must not be less than 125 percent of the fuel flow required to develop
the standard sea level atmospheric conditions takeoff power selected and
included as an operating limitation in the Airplane Flight Manual.
(b) For reciprocating engine powered airplanes, it is acceptable for
the fuel flow rate for each pump system (main and reserve supply) to be
125 percent of the takeoff fuel consumption of the engine.
Fuel System Components
43. Fuel pumps. For turbopropeller powered airplanes, a reliable and
independent power source must be provided for each pump used with
turbine engines which do not have provisions for mechanically driving
the main pumps. It must be demonstrated that the pump installations
provide a reliability and durability equivalent to that provided by FAR
23.991(a).
44. Fuel strainer or filter. For turbopropeller powered airplanes,
the following apply:
(a) There must be a fuel strainer or filter between the tank outlet
and the fuel metering device of the engine. In addition, the fuel
strainer or filter must be--
(1) Between the tank outlet and the engine-driven positive
displacement pump inlet, if there is an engine-driven positive
displacement pump;
(2) Accessible for drainage and cleaning and, for the strainer
screen, easily removable; and
(3) Mounted so that its weight is not supported by the connecting
lines or by the inlet or outlet connections of the strainer or filter
itself.
(b) Unless there are means in the fuel system to prevent the
accumulation of ice on the filter, there must be means to automatically
maintain the fuel flow if ice-clogging of the filter occurs; and
(c) The fuel strainer or filter must be of adequate capacity (with
respect to operating limitations established to insure proper service)
and of appropriate mesh to insure proper engine operation, with the fuel
contaminated to a degree (with respect to particle size and density)
that can be reasonably expected in service. The degree of fuel filtering
may not be less than that established for the engine type certification.
45. Lightning strike protection. Protection must be provided against
the ignition of flammable vapors in the fuel vent system due to
lightning strikes.
Cooling
46. Cooling test procedures for turbopropeller powered airplanes.
(a) Turbopropeller powered airplanes must be shown to comply with the
requirements of FAR 23.1041 during takeoff, climb en route, and landing
stages of flight that correspond to the applicable performance
requirements. The cooling test must be conducted with the airplane in
the configuration and operating under the conditions that are critical
relative to cooling during each stage of flight. For the cooling tests a
temperature is ``stabilized'' when its rate of change is less than 2
[deg]F. per minute.
(b) Temperatures must be stabilized under the conditions from which
entry is made into each stage of flight being investigated unless the
entry condition is not one during which component and engine fluid
temperatures would stabilize, in which case, operation through the full
entry condition must be conducted before entry into the stage of flight
being investigated in order to allow temperatures to reach their natural
levels at the time of entry. The takeoff cooling test must be preceded
by a period during which the powerplant component and engine fluid
temperatures are stabilized with the engines at ground idle.
(c) Cooling tests for each stage of flight must be continued until--
(1) The component and engine fluid temperatures stabilize;
(2) The stage of flight is completed; or
(3) An operating limitation is reached.
Induction System
47. Air induction. For turbopropeller powered airplanes--
(a) There must be means to prevent hazardous quantities of fuel
leakage or overflow from drains, vents, or other components of flammable
fluid systems from entering the engine intake system; and
(b) The air inlet ducts must be located or protected so as to
minimize the ingestion of foreign matter during takeoff, landing, and
taxiing.
48. Induction system icing protection. For turbopropeller powered
airplanes, each turbine engine must be able to operate throughout its
flight power range without adverse effect on engine operation or serious
loss of power or thrust, under the icing conditions specified in
appendix C of FAR 25. In addition, there must be means to indicate to
appropriate flight crewmembers the functioning of the powerplant ice
protection system.
[[Page 179]]
49. Turbine engine bleed air systems. Turbine engine bleed air
systems of turbopropeller powered airplanes must be investigated to
determine--
(a) That no hazard to the airplane will result if a duct rupture
occurs. This condition must consider that a failure of the duct can
occur anywhere between the engine port and the airplane bleed service;
and
(b) That if the bleed air system is used for direct cabin
pressurization, it is not possible for hazardous contamination of the
cabin air system to occur in event of lubrication system failure.
Exhaust System
50. Exhaust system drains. Turbopropeller engine exhaust systems
having low spots or pockets must incorporate drains at such locations.
These drains must discharge clear of the airplane in normal and ground
attitudes to prevent the accumulation of fuel after the failure of an
attempted engine start.
Powerplant Controls and Accessories
51. Engine controls. If throttles or power levers for turbopropeller
powered airplanes are such that any position of these controls will
reduce the fuel flow to the engine(s) below that necessary for
satisfactory and safe idle operation of the engine while the airplane is
in flight, a means must be provided to prevent inadvertent movement of
the control into this position. The means provided must incorporate a
positive lock or stop at this idle position and must require a separate
and distinct operation by the crew to displace the control from the
normal engine operating range.
52. Reverse thrust controls. For turbopropeller powered airplanes,
the propeller reverse thrust controls must have a means to prevent their
inadvertent operation. The means must have a positive lock or stop at
the idle position and must require a separate and distinct operation by
the crew to displace the control from the flight regime.
53. Engine ignition systems. Each turbopropeller airplane ignition
system must be considered an essential electrical load.
54. Powerplant accessories. The powerplant accessories must meet the
requirements of FAR 23.1163, and if the continued rotation of any
accessory remotely driven by the engine is hazardous when malfunctioning
occurs, there must be means to prevent rotation without interfering with
the continued operation of the engine.
Powerplant Fire Protection
55. Fire detector system. For turbopropeller powered airplanes, the
following apply:
(a) There must be a means that ensures prompt detection of fire in
the engine compartment. An overtemperature switch in each engine cooling
air exit is an acceptable method of meeting this requirement.
(b) Each fire detector must be constructed and installed to
withstand the vibration, inertia, and other loads to which it may be
subjected in operation.
(c) No fire detector may be affected by any oil, water, other
fluids, or fumes that might be present.
(d) There must be means to allow the flight crew to check, in
flight, the functioning of each fire detector electric circuit.
(e) Wiring and other components of each fire detector system in a
fire zone must be at least fire resistant.
56. Fire protection, cowling and nacelle skin. For reciprocating
engine powered airplanes, the engine cowling must be designed and
constructed so that no fire originating in the engine compartment can
enter, either through openings or by burn through, any other region
where it would create additional hazards.
57. Flammable fluid fire protection. If flammable fluids or vapors
might be liberated by the leakage of fluid systems in areas other than
engine compartments, there must be means to--
(a) Prevent the ignition of those fluids or vapors by any other
equipment; or
(b) Control any fire resulting from that ignition.
Equipment
58. Powerplant instruments. (a) The following are required for
turbopropeller airplanes:
(1) The instruments required by FAR 23.1305 (a)(1) through (4),
(b)(2) and (4).
(2) A gas temperature indicator for each engine.
(3) Free air temperature indicator.
(4) A fuel flowmeter indicator for each engine.
(5) Oil pressure warning means for each engine.
(6) A torque indicator or adequate means for indicating power output
for each engine.
(7) Fire warning indicator for each engine.
(8) A means to indicate when the propeller blade angle is below the
low-pitch position corresponding to idle operation in flight.
(9) A means to indicate the functioning of the ice protection system
for each engine.
(b) For turbopropeller powered airplanes, the turbopropeller blade
position indicator must begin indicating when the blade has moved below
the flight low-pitch position.
(c) The following instruments are required for reciprocating-engine
powered airplanes:
(1) The instruments required by FAR 23.1305.
(2) A cylinder head temperature indicator for each engine.
(3) A manifold pressure indicator for each engine.
[[Page 180]]
Systems and Equipments
general
59. Function and installation. The systems and equipment of the
airplane must meet the requirements of FAR 23.1301, and the following:
(a) Each item of additional installed equipment must--
(1) Be of a kind and design appropriate to its intended function;
(2) Be labeled as to its identification, function, or operating
limitations, or any applicable combination of these factors, unless
misuse or inadvertent actuation cannot create a hazard;
(3) Be installed according to limitations specified for that
equipment; and
(4) Function properly when installed.
(b) Systems and installations must be designed to safeguard against
hazards to the aircraft in the event of their malfunction or failure.
(c) Where an installation, the functioning of which is necessary in
showing compliance with the applicable requirements, requires a power
supply, such installation must be considered an essential load on the
power supply, and the power sources and the distribution system must be
capable of supplying the following power loads in probable operation
combinations and for probable durations:
(1) All essential loads after failure of any prime mover, power
converter, or energy storage device.
(2) All essential loads after failure of any one engine on two-
engine airplanes.
(3) In determining the probable operating combinations and durations
of essential loads for the power failure conditions described in
subparagraphs (1) and (2) of this paragraph, it is permissible to assume
that the power loads are reduced in accordance with a monitoring
procedure which is consistent with safety in the types of operations
authorized.
60. Ventilation. The ventilation system of the airplane must meet
the requirements of FAR 23.831, and in addition, for pressurized
aircraft the ventilating air in flight crew and passenger compartments
must be free of harmful or hazardous concentrations of gases and vapors
in normal operation and in the event of reasonably probable failures or
malfunctioning of the ventilating, heating, pressurization, or other
systems, and equipment. If accumulation of hazardous quantities of smoke
in the cockpit area is reasonably probable, smoke evacuation must be
readily accomplished.
Electrical Systems and Equipment
61. General. The electrical systems and equipment of the airplane
must meet the requirements of FAR 23.1351, and the following:
(a) Electrical system capacity. The required generating capacity,
and number and kinds of power sources must--
(1) Be determined by an electrical load analysis, and
(2) Meet the requirements of FAR 23.1301.
(b) Generating system. The generating system includes electrical
power sources, main power busses, transmission cables, and associated
control, regulation, and protective devices. It must be designed so
that--
(1) The system voltage and frequency (as applicable) at the
terminals of all essential load equipment can be maintained within the
limits for which the equipment is designed, during any probable
operating conditions;
(2) System transients due to switching, fault clearing, or other
causes do not make essential loads inoperative, and do not cause a smoke
or fire hazard;
(3) There are means, accessible in flight to appropriate
crewmembers, for the individual and collective disconnection of the
electrical power sources from the system; and
(4) There are means to indicate to appropriate crewmembers the
generating system quantities essential for the safe operation of the
system, including the voltage and current supplied by each generator.
62. Electrical equipment and installation. Electrical equipment
controls, and wiring must be installed so that operation of any one unit
or system of units will not adversely affect the simultaneous operation
of to the safe operation.
63. Distribution system. (a) For the purpose of complying with this
section, the distribution system includes the distribution busses, their
associated feeders and each control and protective device.
(b) Each system must be designed so that essential load circuits can
be supplied in the event of reasonably probable faults or open circuits,
including faults in heavy current carrying cables.
(c) If two independent sources of electrical power for particular
equipment or systems are required by this regulation, their electrical
energy supply must be insured by means such as duplicate electrical
equipment, throwover switching, or multichannel or loop circuits
separately routed.
64. Circuit protective devices. The circuit protective devices for
the electrical circuits of the airplane must meet the requirements of
FAR 23.1357, and in addition circuits for loads which are essential to
safe operation must have individual and exclusive circuit protection.
[Doc. No. 8070, 34 FR 189, Jan. 7, 1969, as amended by SFAR 23-1, 34 FR
20176, Dec. 24, 1969; 35 FR 1102, Jan. 28, 1970]
[[Page 181]]
(a) This part prescribes airworthiness standards for the issue of
type certificates, and changes to those certificates, for airplanes in
the normal, utility, acrobatic, and commuter categories.
(b) Each person who applies under Part 21 for such a certificate or
change must show compliance with the applicable requirements of this
part.
[Doc. No. 4080, 29 FR 17955, Dec. 18, 1964, as amended by Amdt. 23-34,
52 FR 1825, Jan. 15, 1987]