Part 25: Airworthiness standards: Transport category airplanes

Special Federal Aviation Regulations

• SFAR No. 13

Federal Aviation Regulations

Subpart A - General

• Sec. 25.1 - Applicability.
• Sec. 25.2 - Special retroactive requirements.

Subpart B - Flight
 

• Sec. 25.21 - Proof of compliance.
• Sec. 25.23 - Load distribution limits.
• Sec. 25.25 - Weight limits.
• Sec. 25.27 - Center of gravity limits.
• Sec. 25.29 - Empty weight and corresponding center of gravity.
• Sec. 25.31 - Removable ballast.
• Sec. 25.33 - Propeller speed and pitch limits.
• Sec. 25.101 - General.
• Sec. 25.103 - Stall speed.
• Sec. 25.105 - Takeoff.
• Sec. 25.107 - Takeoff speeds.
• Sec. 25.109 - Accelerate-stop distance.
• Sec. 25.111 - Takeoff path.
• Sec. 25.113 - Takeoff distance and takeoff run.
• Sec. 25.115 - Takeoff flight path.
• Sec. 25.117 - Climb: general.
• Sec. 25.119 - Landing climb: All-engines-operating.
• Sec. 25.121 - Climb: One-engine-inoperative.
• Sec. 25.123 - En route flight paths.
• Sec. 25.125 - Landing.
• Sec. 25.143 - General.
• Sec. 25.145 - Longitudinal control.
• Sec. 25.147 - Directional and lateral control.
• Sec. 25.149 - Minimum control speed.
• Sec. 25.161 - Trim.
• Sec. 25.171 - General.
• Sec. 25.173 - Static longitudinal stability.
• Sec. 25.175 - Demonstration of static longitudinal stability.
• Sec. 25.177 - Static lateral-directional stability.
• Sec. 25.181 - Dynamic stability.
• Sec. 25.201 - Stall demonstration.
• Sec. 25.203 - Stall characteristics.
• Sec. 25.207 - Stall warning.
• Sec. 25.231 - Longitudinal stability and control.
• Sec. 25.233 - Directional stability and control.
• Sec. 25.235 - Taxiing condition.
• Sec. 25.237 - Wind velocities.
• Sec. 25.239 - Spray characteristics, control, and stability on water.
• Sec. 25.251 - Vibration and buffeting.
• Sec. 25.253 - High-speed characteristics.
• Sec. 25.255 - Out-of-trim characteristics.

Subpart C - Structure
 

• Sec. 25.301 - Loads.
• Sec. 25.303 - Factor of safety.
• Sec. 25.305 - Strength and deformation.
• Sec. 25.307 - Proof of structure.
• Sec. 25.321 - General.
• Sec. 25.331 - Symmetric manoeuvring conditions.
• Sec. 25.333 - Flight manoeuvring envelope.
• Sec. 25.335 - Design airspeeds.
• Sec. 25.337 - Limit manoeuvring load factors.
• Sec. 25.341 - Gust and turbulence loads.
• Sec. 25.343 - Design fuel and oil loads.
• Sec. 25.345 - High lift devices.
• Sec. 25.349 - Rolling conditions.
• Sec. 25.351 - Yaw manoeuvre conditions.
• Sec. 25.361 - Engine torque.
• Sec. 25.363 - Side load on engine and auxiliary power unit mounts.
• Sec. 25.365 - Pressurized compartment loads.
• Sec. 25.367 - Unsymmetrical loads due to engine failure.
• Sec. 25.371 - Gyroscopic loads.
• Sec. 25.373 - Speed control devices.
• Sec. 25.391 - Control surface loads: General.
• Sec. 25.393 - Loads parallel to hinge line.
• Sec. 25.395 - Control system.
• Sec. 25.397 - Control system loads.
• Sec. 25.399 - Dual control system.
• Sec. 25.405 - Secondary control system.
• Sec. 25.407 - Trim tab effects.
• Sec. 25.409 - Tabs.
• Sec. 25.415 - Ground gust conditions.
• Sec. 25.427 - Unsymmetrical loads.
• Sec. 25.445 - Auxiliary aerodynamic surfaces.
• Sec. 25.457 - Wing flaps.
• Sec. 25.459 - Special devices.
• Sec. 25.471 - General.
• Sec. 25.473 - Landing load conditions and assumptions.
• Sec. 25.477 - Landing gear arrangement.
• Sec. 25.479 - Level landing conditions.
• Sec. 25.481 - Tail-down landing conditions.
• Sec. 25.483 - One-gear landing conditions.
• Sec. 25.485 - Side load conditions.
• Sec. 25.487 - Rebound landing condition.
• Sec. 25.489 - Ground handling conditions.
• Sec. 25.491 - Taxi, takeoff and landing roll.
• Sec. 25.493 - Braked roll conditions.
• Sec. 25.495 - Turning.
• Sec. 25.497 - Tail-wheel yawing.
• Sec. 25.499 - Nose-wheel yaw and steering.
• Sec. 25.503 - Pivoting.
• Sec. 25.507 - Reversed braking.
• Sec. 25.509 - Towing loads.
• Sec. 25.511 - Ground load: unsymmetrical loads on multiple-wheel units.
• Sec. 25.519 - Jacking and tie-down provisions.
• Sec. 25.521 - General.
• Sec. 25.523 - Design weights and center of gravity positions.
• Sec. 25.525 - Application of loads.
• Sec. 25.527 - Hull and main float load factors.
• Sec. 25.529 - Hull and main float landing conditions.
• Sec. 25.531 - Hull and main float takeoff condition.
• Sec. 25.533 - Hull and main float bottom pressures.
• Sec. 25.535 - Auxiliary float loads.
• Sec. 25.537 - Seawing loads.
• Sec. 25.561 - General.
• Sec. 25.562 - Emergency landing dynamic conditions.
• Sec. 25.563 - Structural ditching provisions.
• Sec. 25.571 - Damage -- tolerance and fatigue evaluation of structure.
• Sec. 25.581 - Lightning protection.

Subpart D - Design and Construction
 

• Sec. 25.601 - General.
• Sec. 25.603 - Materials.
• Sec. 25.605 - Fabrication methods.
• Sec. 25.607 - Fasteners.
• Sec. 25.609 - Protection of structure.
• Sec. 25.611 - Accessibility provisions.
• Sec. 25.613 - Material strength properties and design values.
• Sec. 25.619 - Special factors.
• Sec. 25.621 - Casting factors.
• Sec. 25.623 - Bearing factors.
• Sec. 25.625 - Fitting factors.
• Sec. 25.629 - Aeroelastic stability requirements.
• Sec. 25.631 - Bird strike damage.
• Sec. 25.651 - Proof of strength.
• Sec. 25.655 - Installation.
• Sec. 25.657 - Hinges.
• Sec. 25.671 - General.
• Sec. 25.672 - Stability augmentation and automatic and power-operated systems.
• Sec. 25.675 - Stops.
• Sec. 25.677 - Trim systems.
• Sec. 25.679 - Control system gust locks.
• Sec. 25.681 - Limit load static tests.
• Sec. 25.683 - Operation tests.
• Sec. 25.685 - Control system details.
• Sec. 25.689 - Cable systems.
• Sec. 25.693 - Joints.
• Sec. 25.697 - Lift and drag devices, controls.
• Sec. 25.699 - Lift and drag device indicator.
• Sec. 25.701 - Flap and slat interconnection.
• Sec. 25.703 - Takeoff warning system.
• Sec. 25.721 - General.
• Sec. 25.723 - Shock absorption tests.
• Sec. 25.725 - [Reserved]
• Sec. 25.727 - [Reserved]
• Sec. 25.729 - Retracting mechanism.
• Sec. 25.731 - Wheels.
• Sec. 25.733 - Tires.
• Sec. 25.735 - Brakes and braking systems.
• Sec. 25.737 - Skis.
• Sec. 25.751 - Main float buoyancy.
• Sec. 25.753 - Main float design.
• Sec. 25.755 - Hulls.
• Sec. 25.771 - Pilot compartment.
• Sec. 25.772 - Pilot compartment doors.
• Sec. 25.773 - Pilot compartment view.
• Sec. 25.775 - Windshields and windows.
• Sec. 25.777 - Cockpit controls.
• Sec. 25.779 - Motion and effect of cockpit controls.
• Sec. 25.781 - Cockpit control knob shape.
• Sec. 25.783 - Doors.
• Sec. 25.785 - Seats, berths, safety belts, and harnesses.
• Sec. 25.787 - Stowage compartments.
• Sec. 25.789 - Retention of items of mass in passenger and crew compartments and galleys.
• Sec. 25.791 - Passenger information signs and placards.
• Sec. 25.793 - Floor surfaces.
• Sec. 25.795 - Security considerations.
• Sec. 25.801 - Ditching.
• Sec. 25.803 - Emergency evacuation.
• Sec. 25.807 - Emergency exits.
• Sec. 25.809 - Emergency exit arrangement.
• Sec. 25.810 - Emergency egress assist means and escape routes.
• Sec. 25.811 - Emergency exit marking.
• Sec. 25.812 - Emergency lighting.
• Sec. 25.813 - Emergency exit access.
• Sec. 25.815 - Width of aisle.
• Sec. 25.817 - Maximum number of seats abreast.
• Sec. 25.819 - Lower deck service compartments (including galleys).
• Sec. 25.831 - Ventilation.
• Sec. 25.832 - Cabin ozone concentration.
• Sec. 25.833 - Combustion heating systems.
• Sec. 25.841 - Pressurized cabins.
• Sec. 25.843 - Tests for pressurized cabins.
• Sec. 25.851 - Fire extinguishers.
• Sec. 25.853 - Compartment interiors.
• Sec. 25.854 - Lavatory fire protection.
• Sec. 25.855 - Cargo or baggage compartments.
• Sec. 25.857 - Cargo compartment classification.
• Sec. 25.858 - Cargo or baggage compartment smoke or fire detection systems.
• Sec. 25.859 - Combustion heater fire protection.
• Sec. 25.863 - Flammable fluid fire protection.
• Sec. 25.865 - Fire protection of flight controls, engine mounts, and other flight structure.
• Sec. 25.867 - Fire protection: other components.
• Sec. 25.869 - Fire protection: systems.
• Sec. 25.871 - Leveling means.
• Sec. 25.875 - Reinforcement near propellers.

Subpart E - Powerplant

• Sec. 25.901 - Installation.
• Sec. 25.903 - 25
• Sec. 25.904 - Automatic takeoff thrust control system (ATTCS).
• Sec. 25.905 - Propellers.
• Sec. 25.907 - Propeller vibration.
• Sec. 25.925 - Propeller clearance.
• Sec. 25.929 - Propeller deicing.
• Sec. 25.933 - Reversing systems.
• Sec. 25.934 - Turbojet engine thrust reverser system tests.
• Sec. 25.937 - Turbopropeller-drag limiting systems.
• Sec. 25.939 - Turbine engine operating characteristics.
• Sec. 25.941 - Inlet, engine, and exhaust compatibility.
• Sec. 25.943 - Negative acceleration.
• Sec. 25.945 - Thrust or power augmentation system.
• Sec. 25.951 - General.
• Sec. 25.952 - Fuel system analysis and test.
• Sec. 25.953 - Fuel system independence.
• Sec. 25.954 - Fuel system lightning protection.
• Sec. 25.955 - Fuel flow.
• Sec. 25.957 - Flow between interconnected tanks.
• Sec. 25.959 - Unusable fuel supply.
• Sec. 25.961 - Fuel system hot weather operation.
• Sec. 25.963 - Fuel tanks: general.
• Sec. 25.965 - Fuel tank tests.
• Sec. 25.967 - Fuel tank installations.
• Sec. 25.969 - Fuel tank expansion space.
• Sec. 25.971 - Fuel tank sump.
• Sec. 25.973 - Fuel tank filler connection.
• Sec. 25.975 - Fuel tank vents and carburetor vapor vents.
• Sec. 25.977 - Fuel tank outlet.
• Sec. 25.979 - Pressure fueling system.
• Sec. 25.981 - Fuel tank ignition prevention.
• Sec. 25.991 - Fuel pumps.
• Sec. 25.993 - Fuel system lines and fittings.
• Sec. 25.994 - Fuel system components.
• Sec. 25.995 - Fuel valves.
• Sec. 25.997 - Fuel strainer or filter.
• Sec. 25.999 - Fuel system drains.
• Sec. 25.1001 - Fuel jettisoning system.
• Sec. 25.1011 - General.
• Sec. 25.1013 - Oil tanks.
• Sec. 25.1015 - Oil tank tests.
• Sec. 25.1017 - Oil lines and fittings.
• Sec. 25.1019 - Oil strainer or filter.
• Sec. 25.1021 - Oil system drains.
• Sec. 25.1023 - Oil radiators.
• Sec. 25.1025 - Oil valves.
• Sec. 25.1027 - Propeller feathering system.
• Sec. 25.1041 - General.
• Sec. 25.1043 - Cooling tests.
• Sec. 25.1045 - Cooling test procedures.
• Sec. 25.1091 - 25
• Sec. 25.1093 - Induction system icing protection.
• Sec. 25.1101 - Carburetor air preheater design.
• Sec. 25.1103 - Induction system ducts and air duct systems.
• Sec. 25.1105 - Induction system screens.
• Sec. 25.1107 - Inter-coolers and after-coolers.
• Sec. 25.1121 - General.
• Sec. 25.1123 - Exhaust piping.
• Sec. 25.1125 - Exhaust heat exchangers.
• Sec. 25.1127 - Exhaust driven turbo-superchargers.
• Sec. 25.1141 - Powerplant controls: general.
• Sec. 25.1142 - Auxiliary power unit controls.
• Sec. 25.1143 - Engine controls.
• Sec. 25.1145 - Ignition switches.
• Sec. 25.1147 - Mixture controls.
• Sec. 25.1149 - Propeller speed and pitch controls.
• Sec. 25.1153 - Propeller feathering controls.
• Sec. 25.1155 - Reverse thrust and propeller pitch settings below the flight regime.
• Sec. 25.1157 - Carburetor air temperature controls.
• Sec. 25.1159 - Supercharger controls.
• Sec. 25.1161 - Fuel jettisoning system controls.
• Sec. 25.1163 - Powerplant accessories.
• Sec. 25.1165 - Engine ignition systems.
• Sec. 25.1167 - Accessory gearboxes.
• Sec. 25.1181 - Designated fire zones; regions included.
• Sec. 25.1182 - Nacelle areas behind firewalls, and engine pod attaching structures containing flammable fluid lines.
• Sec. 25.1183 - 25
• Sec. 25.1185 - Flammable fluids.
• Sec. 25.1187 - Drainage and ventilation of fire zones.
• Sec. 25.1189 - Shutoff means.
• Sec. 25.1191 - Firewalls.
• Sec. 25.1192 - Engine accessory section diaphragm.
• Sec. 25.1193 - Cowling and nacelle skin.
• Sec. 25.1195 - Fire extinguishing systems.
• Sec. 25.1197 - Fire extinguishing agents.
• Sec. 25.1199 - Extinguishing agent containers.
• Sec. 25.1201 - Fire extinguishing system materials.
• Sec. 25.1203 - Fire detector system.
• Sec. 25.1207 - Compliance.

Subpart F - Equipment
 

• Sec. 25.1301 - Function and installation.
• Sec. 25.1303 - Flight and navigation instruments.
• Sec. 25.1305 - Powerplant instruments.
• Sec. 25.1307 - Miscellaneous equipment.
• Sec. 25.1309 - Equipment, systems, and installations.
• Sec. 25.1316 - System lightning protection.
• Sec. 25.1321 - Arrangement and visibility.
• Sec. 25.1322 - Warning, caution, and advisory lights.
• Sec. 25.1323 - Airspeed indicating system.
• Sec. 25.1325 - Static pressure systems.
• Sec. 25.1326 - Pitot heat indication systems.
• Sec. 25.1327 - Magnetic direction indicator.
• Sec. 25.1329 - Automatic pilot system.
• Sec. 25.1331 - Instruments using a power supply.
• Sec. 25.1333 - Instrument systems.
• Sec. 25.1335 - Flight director systems.
• Sec. 25.1337 - Powerplant instruments.
• Sec. 25.1351 - General.
• Sec. 25.1353 - Electrical equipment and installations.
• Sec. 25.1355 - Distribution system.
• Sec. 25.1357 - Circuit protective devices.
• Sec. 25.1363 - Electrical system tests.
• Sec. 25.1381 - Instrument lights.
• Sec. 25.1383 - Landing lights.
• Sec. 25.1385 - Position light system installation.
• Sec. 25.1387 - Position light system dihedral angles.
• Sec. 25.1389 - Position light distribution and intensities.
• Sec. 25.1391 - Minimum intensities in the horizontal plane of forward and rear position lights.
• Sec. 25.1393 - Minimum intensities in any vertical plane of forward and rear position lights.
• Sec. 25.1395 - Maximum intensities in overlapping beams of forward and rear position lights.
• Sec. 25.1397 - Color specifications.
• Sec. 25.1399 - Riding light.
• Sec. 25.1401 - Anticollision light system.
• Sec. 25.1403 - Wing icing detection lights.
• Sec. 25.1411 - General.
• Sec. 25.1415 - Ditching equipment.
• Sec. 25.1419 - Ice protection.
• Sec. 25.1421 - Megaphones.
• Sec. 25.1423 - Public address system.
• Sec. 25.1431 - Electronic equipment.
• Sec. 25.1433 - Vacuum systems.
• Sec. 25.1435 - Hydraulic systems.
• Sec. 25.1438 - Pressurization and pneumatic systems.
• Sec. 25.1439 - Protective breathing equipment.
• Sec. 25.1441 - Oxygen equipment and supply.
• Sec. 25.1443 - Minimum mass flow of supplemental oxygen.
• Sec. 25.1445 - Equipment standards for the oxygen distributing system.
• Sec. 25.1447 - Equipment standards for oxygen dispensing units.
• Sec. 25.1449 - Means for determining use of oxygen.
• Sec. 25.1450 - Chemical oxygen generators.
• Sec. 25.1453 - Protection of oxygen equipment from rupture.
• Sec. 25.1455 - Draining of fluids subject to freezing.
• Sec. 25.1457 - Cockpit voice recorders.
• Sec. 25.1459 - Flight recorders.
• Sec. 25.1461 - Equipment containing high energy rotors.

Subpart G - Operating Limitations and Information
 

• Sec. 25.1501 - General.
• Sec. 25.1503 - Airspeed limitations: general.
• Sec. 25.1505 - Maximum operating limit speed.
• Sec. 25.1507 - Manoeuvring speed.
• Sec. 25.1511 - Flap extended speed.
• Sec. 25.1513 - Minimum control speed.
• Sec. 25.1515 - Landing gear speeds.
• Sec. 25.1516 - 25
• Sec. 25.1517 - Rough air speed, VRA.
• Sec. 25.1519 - Weight, center of gravity, and weight distribution.
• Sec. 25.1521 - Powerplant limitations.
• Sec. 25.1522 - Auxiliary power unit limitations.
• Sec. 25.1523 - Minimum flight crew.
• Sec. 25.1525 - Kinds of operation.
• Sec. 25.1527 - Ambient air temperature and operating altitude.
• Sec. 25.1529 - Instructions for Continued Airworthiness.
• Sec. 25.1531 - Manoeuvring flight load factors.
• Sec. 25.1533 - Additional operating limitations.
• Sec. 25.1541 - General.
• Sec. 25.1543 - Instrument markings: general.
• Sec. 25.1545 - Airspeed limitation information.
• Sec. 25.1547 - Magnetic direction indicator.
• Sec. 25.1549 - Powerplant and auxiliary power unit instruments.
• Sec. 25.1551 - Oil quantity indication.
• Sec. 25.1553 - Fuel quantity indicator.
• Sec. 25.1555 - Control markings.
• Sec. 25.1557 - Miscellaneous markings and placards.
• Sec. 25.1561 - Safety equipment.
• Sec. 25.1563 - Airspeed placard.
• Sec. 25.1581 - General.
• Sec. 25.1583 - 25
• Sec. 25.1585 - Operating procedures.
• Sec. 25.1587 - Performance information.

Appendices

• Appendix G to Part 25 - Continuous Gust Design Criteria
• Appendix H to Part 25 - Instructions for Continued Airworthiness
• Appendix J to Part 25 - Emergency Evacuation

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