14 CFR Part 121 — Operating Requirements: Domestic, Flag, and Supplemental Operations

14 CFR part 121· eCFR as of 2026-09-29Official source

14 CFR § 121.1 Applicability.
14 CFR § 121.2 Compliance schedule for operators that transition to part 121; certain new entrant operators.
14 CFR § 121.4 Applicability of rules to unauthorized operators.
14 CFR § 121.7 Definitions.
14 CFR § 121.11 Rules applicable to operations in a foreign country.
14 CFR § 121.15 Carriage of narcotic drugs, marihuana, and depressant or stimulant drugs or substances.
14 CFR § 121.91 Applicability.
14 CFR § 121.93 Route requirements: General.
14 CFR § 121.95 Route width.
14 CFR § 121.97 Airports: Required data.
14 CFR § 121.99 Communications facilities—domestic and flag operations.
14 CFR § 121.101 Weather reporting facilities.
14 CFR § 121.103 En route navigation facilities.
14 CFR § 121.105 Servicing and maintenance facilities.
14 CFR § 121.106 ETOPS Alternate Airport: Rescue and fire fighting service.
14 CFR § 121.107 Dispatch centers.
14 CFR § 121.111 Applicability.
14 CFR § 121.113 Area and route requirements: General.
14 CFR § 121.115 Route width.
14 CFR § 121.117 Airports: Required data.
14 CFR § 121.119 Weather reporting facilities.
14 CFR § 121.121 En route navigation facilities.
14 CFR § 121.122 Communications facilities—supplemental operations.
14 CFR § 121.123 Servicing maintenance facilities.
14 CFR § 121.125 Flight following system.
14 CFR § 121.127 Flight following system; requirements.
14 CFR § 121.131 Applicability.
14 CFR § 121.133 Preparation.
14 CFR § 121.135 Manual contents.
14 CFR § 121.137 Distribution and availability.
14 CFR § 121.139 Manual accessibility: Supplemental operations.
14 CFR § 121.141 Airplane flight manual.
14 CFR § 121.151 Applicability.
14 CFR § 121.153 Aircraft requirements: General.
14 CFR § 121.157 Aircraft certification and equipment requirements.
14 CFR § 121.159 Single-engine airplanes prohibited.
14 CFR § 121.161 Airplane limitations: Type of route.
14 CFR § 121.162 ETOPS Type Design Approval Basis.
14 CFR § 121.163 Aircraft proving tests.
14 CFR § 121.171 Applicability.
14 CFR § 121.173 General.
14 CFR § 121.175 Airplanes: Reciprocating engine-powered: Weight limitations.
14 CFR § 121.177 Airplanes: Reciprocating engine-powered: Takeoff limitations.
14 CFR § 121.179 Airplanes: Reciprocating engine-powered: En route limitations: All engines operating.
14 CFR § 121.181 Airplanes: Reciprocating engine-powered: En route limitations: One engine inoperative.
14 CFR § 121.183 Part 25 airplanes with four or more engines: Reciprocating engine powered: En route limitations: Two engines inoperative.
14 CFR § 121.185 Airplanes: Reciprocating engine-powered: Landing limitations: Destination airport.
14 CFR § 121.187 Airplanes: Reciprocating engine-powered: Landing limitations: Alternate airport.
14 CFR § 121.189 Airplanes: Turbine engine powered: Takeoff limitations.
14 CFR § 121.191 Airplanes: Turbine engine powered: En route limitations: One engine inoperative.
14 CFR § 121.193 Airplanes: Turbine engine powered: En route limitations: Two engines inoperative.
14 CFR § 121.195 Airplanes: Turbine engine powered: Landing limitations: Destination airports.
14 CFR § 121.197 Airplanes: Turbine engine powered: Landing limitations: Alternate airports.
14 CFR § 121.198 Cargo service airplanes: Increased zero fuel and landing weights.
14 CFR § 121.199 Nontransport category airplanes: Takeoff limitations.
14 CFR § 121.201 Nontransport category airplanes: En route limitations: One engine inoperative.
14 CFR § 121.203 Nontransport category airplanes: Landing limitations: Destination airport.
14 CFR § 121.205 Nontransport category airplanes: Landing limitations: Alternate airport.
14 CFR § 121.207 Provisionally certificated airplanes: Operating limitations.
14 CFR § 121.211 Applicability.
14 CFR § 121.215 Cabin interiors.
14 CFR § 121.217 Internal doors.
14 CFR § 121.219 Ventilation.
14 CFR § 121.221 Fire precautions.
14 CFR § 121.223 Proof of compliance with § 121.221.
14 CFR § 121.225 Propeller deicing fluid.
14 CFR § 121.227 Pressure cross-feed arrangements.
14 CFR § 121.229 Location of fuel tanks.
14 CFR § 121.231 Fuel system lines and fittings.
14 CFR § 121.233 Fuel lines and fittings in designated fire zones.
14 CFR § 121.235 Fuel valves.
14 CFR § 121.237 Oil lines and fittings in designated fire zones.
14 CFR § 121.239 Oil valves.
14 CFR § 121.241 Oil system drains.
14 CFR § 121.243 Engine breather lines.
14 CFR § 121.245 Fire walls.
14 CFR § 121.247 Fire-wall construction.
14 CFR § 121.249 Cowling.
14 CFR § 121.251 Engine accessory section diaphragm.
14 CFR § 121.253 Powerplant fire protection.
14 CFR § 121.255 Flammable fluids.
14 CFR § 121.257 Shutoff means.
14 CFR § 121.259 Lines and fittings.
14 CFR § 121.261 Vent and drain lines.
14 CFR § 121.263 Fire-extinguishing systems.
14 CFR § 121.265 Fire-extinguishing agents.
14 CFR § 121.267 Extinguishing agent container pressure relief.
14 CFR § 121.269 Extinguishing agent container compartment temperature.
14 CFR § 121.271 Fire-extinguishing system materials.
14 CFR § 121.273 Fire-detector systems.
14 CFR § 121.275 Fire detectors.
14 CFR § 121.277 Protection of other airplane components against fire.
14 CFR § 121.279 Control of engine rotation.
14 CFR § 121.281 Fuel system independence.
14 CFR § 121.283 Induction system ice prevention.
14 CFR § 121.285 Carriage of cargo in passenger compartments.
14 CFR § 121.287 Carriage of cargo in cargo compartments.
14 CFR § 121.289 Landing gear: Aural warning device.
14 CFR § 121.291 Demonstration of emergency evacuation procedures.
14 CFR § 121.293 Special airworthiness requirements for nontransport category airplanes type certificated after December 31, 1964.
14 CFR § 121.295 Location for a suspect device.
14 CFR § 121.301 Applicability.
14 CFR § 121.303 Airplane instruments and equipment.
14 CFR § 121.305 Flight and navigational equipment.
14 CFR § 121.306 Portable electronic devices.
14 CFR § 121.307 Engine instruments.
14 CFR § 121.308 Lavatory fire protection.
14 CFR § 121.309 Emergency equipment.
14 CFR § 121.310 Additional emergency equipment.
14 CFR § 121.311 Seats, safety belts, and shoulder harnesses.
14 CFR § 121.312 Materials for compartment interiors.
14 CFR § 121.313 Miscellaneous equipment.
14 CFR § 121.314 Cargo and baggage compartments.
14 CFR § 121.315 Cockpit check procedure.
14 CFR § 121.316 Fuel tanks.
14 CFR § 121.317 Passenger information requirements, smoking prohibitions, and additional seat belt requirements.
14 CFR § 121.318 Public address system.
14 CFR § 121.319 Crewmember interphone system.
14 CFR § 121.321 Operations in icing.
14 CFR § 121.323 Instruments and equipment for operations at night.
14 CFR § 121.325 Instruments and equipment for operations under IFR or over-the-top.
14 CFR § 121.326 Radio Altimeter Systems.
14 CFR § 121.327 Supplemental oxygen: Reciprocating engine powered airplanes.
14 CFR § 121.329 Supplemental oxygen for sustenance: Turbine engine powered airplanes.
14 CFR § 121.331 Supplemental oxygen requirements for pressurized cabin airplanes: Reciprocating engine powered airplanes.
14 CFR § 121.333 Supplemental oxygen for emergency descent and for first aid; turbine engine powered airplanes with pressurized cabins.
14 CFR § 121.335 Equipment standards.
14 CFR § 121.337 Protective breathing equipment.
14 CFR § 121.339 Emergency equipment for extended over-water operations.
14 CFR § 121.340 Emergency flotation means.
14 CFR § 121.341 Equipment for operations in icing conditions.
14 CFR § 121.342 Pitot heat indication systems.
14 CFR § 121.343 Flight data recorders.
14 CFR § 121.344 Digital flight data recorders for transport category airplanes.
14 CFR § 121.344a Digital flight data recorders for 10-19 seat airplanes.
14 CFR § 121.345 Radio equipment.
14 CFR § 121.346 Flight data recorders: filtered data.
14 CFR § 121.347 Communication and navigation equipment for operations under VFR over routes navigated by pilotage.
14 CFR § 121.349 Communication and navigation equipment for operations under VFR over routes not navigated by pilotage or for operations under IFR or over the top.
14 CFR § 121.351 Communication and navigation equipment for extended over-water operations and for certain other operations.
14 CFR § 121.353 Emergency equipment for operations over uninhabited terrain areas: Flag, supplemental, and certain domestic operations.
14 CFR § 121.354 Terrain awareness and warning system.
14 CFR § 121.355 Equipment for operations on which specialized means of navigation are used.
14 CFR § 121.356 Collision avoidance system.
14 CFR § 121.357 Airborne weather radar equipment requirements.
14 CFR § 121.358 Low-altitude windshear system equipment requirements.
14 CFR § 121.359 Cockpit voice recorders.
14 CFR § 121.361 Applicability.
14 CFR § 121.363 Responsibility for airworthiness.
14 CFR § 121.365 Maintenance, preventive maintenance, and alteration organization.
14 CFR § 121.367 Maintenance, preventive maintenance, and alterations programs.
14 CFR § 121.368 Contract maintenance.
14 CFR § 121.369 Manual requirements.
14 CFR § 121.371 Required inspection personnel.
14 CFR § 121.373 Continuing analysis and surveillance.
14 CFR § 121.374 Continuous airworthiness maintenance program (CAMP) for two-engine ETOPS.
14 CFR § 121.375 Maintenance and preventive maintenance training program.
14 CFR § 121.377 Maintenance and preventive maintenance personnel duty time limitations.
14 CFR § 121.378 Certificate requirements.
14 CFR § 121.379 Authority to perform and approve maintenance, preventive maintenance, and alterations.
14 CFR § 121.380 Maintenance recording requirements.
14 CFR § 121.380a Transfer of maintenance records.
14 CFR § 121.381 Applicability.
14 CFR § 121.383 Airman: Limitations on use of services.
14 CFR § 121.385 Composition of flight crew.
14 CFR § 121.387 Flight engineer.
14 CFR § 121.389 Flight navigator and specialized navigation equipment.
14 CFR § 121.391 Flight attendants.
14 CFR § 121.392 Personnel identified as flight attendants.
14 CFR § 121.393 Crewmember requirements at stops where passengers remain on board.
14 CFR § 121.394 Flight attendant requirements during passenger boarding and deplaning.
14 CFR § 121.395 Aircraft dispatcher: Domestic and flag operations.
14 CFR § 121.397 Emergency and emergency evacuation duties.
14 CFR § 121.400 Applicability and terms used.
14 CFR § 121.401 Training program: General.
14 CFR § 121.402 Training program: Special rules.
14 CFR § 121.403 Training program: Curriculum.
14 CFR § 121.404 Crew and dispatcher resource management training.
14 CFR § 121.405 Training program and revision: Initial and final approval.
14 CFR § 121.406 Credit for previous CRM/DRM training.
14 CFR § 121.407 Training program: Approval of flight simulation training devices.
14 CFR § 121.408 Training equipment other than flight simulation training devices.
14 CFR § 121.409 Training courses using flight simulation training devices.
14 CFR § 121.410 Airline transport pilot certification training program.
14 CFR § 121.411 Qualifications: Check pilots and check flight engineers.
14 CFR § 121.412 Qualifications: Flight instructors.
14 CFR § 121.413 Initial, transition and recurrent training and checking requirements: Check pilots and check flight engineers.
14 CFR § 121.414 Initial, transition and recurrent training and checking requirements: Flight instructors.
14 CFR § 121.415 Crewmember and dispatcher training program requirements.
14 CFR § 121.417 Crewmember emergency training.
14 CFR § 121.418 Differences training and related aircraft differences training.
14 CFR § 121.419 Pilots and flight engineers: Initial, transition, conversion and upgrade ground training.
14 CFR § 121.420 Pilots: Upgrade ground training.
14 CFR § 121.421 Flight attendants: Initial and transition ground training.
14 CFR § 121.422 Aircraft dispatchers: Initial and transition ground training.
14 CFR § 121.423 Pilots: Extended Envelope Training.
14 CFR § 121.424 Pilots: Initial, transition, conversion, and upgrade flight training.
14 CFR § 121.425 Flight engineers: Initial and transition flight training.
14 CFR § 121.426 Pilots: Upgrade flight training.
14 CFR § 121.427 Recurrent training.
14 CFR § 121.429 Pilots in command: Leadership and command and mentoring training.
14 CFR § 121.431 Applicability.
14 CFR § 121.432 General.
14 CFR § 121.433 Training required.
14 CFR § 121.434 Operating experience, operating cycles, and consolidation of knowledge and skills.
14 CFR § 121.435 Pilots: Operations Familiarization.
14 CFR § 121.436 Pilot Qualification: Certificates and experience requirements.
14 CFR § 121.438 Pilot operating limitations and pairing requirements.
14 CFR § 121.439 Pilot qualification: Recent experience.
14 CFR § 121.440 Line checks.
14 CFR § 121.441 Proficiency checks.
14 CFR § 121.443 Pilot in command qualification: Route and airports.
14 CFR § 121.445 Pilot in command airport qualification: Special areas and airports.
14 CFR § 121.453 Flight engineer qualifications.
14 CFR § 121.461 Applicability.
14 CFR § 121.463 Aircraft dispatcher qualifications.
14 CFR § 121.465 Aircraft dispatcher duty time limitations: Domestic and flag operations.
14 CFR § 121.467 Flight attendant duty period limitations and rest requirements: Domestic, flag, and supplemental operations.
14 CFR § 121.470 Applicability.
14 CFR § 121.471 Flight time limitations and rest requirements: All flight crewmembers.
14 CFR § 121.473 Fatigue risk management system.
14 CFR § 121.480 Applicability.
14 CFR § 121.481 Flight time limitations: One or two pilot crews.
14 CFR § 121.483 Flight time limitations: Two pilots and one additional flight crewmember.
14 CFR § 121.485 Flight time limitations: Three or more pilots and an additional flight crewmember.
14 CFR § 121.487 Flight time limitations: Pilots not regularly assigned.
14 CFR § 121.489 Flight time limitations: Other commercial flying.
14 CFR § 121.491 Flight time limitations: Deadhead transportation.
14 CFR § 121.493 Flight time limitations: Flight engineers and flight navigators.
14 CFR § 121.495 Fatigue risk management system.
14 CFR § 121.500 Applicability.
14 CFR § 121.503 Flight time limitations: Pilots: airplanes.
14 CFR § 121.505 Flight time limitations: Two pilot crews: airplanes.
14 CFR § 121.507 Flight time limitations: Three pilot crews: airplanes.
14 CFR § 121.509 Flight time limitations: Four pilot crews: airplanes.
14 CFR § 121.511 Flight time limitations: Flight engineers: airplanes.
14 CFR § 121.513 Flight time limitations: Overseas and international operations: airplanes.
14 CFR § 121.515 Flight time limitations: All airmen: airplanes.
14 CFR § 121.517 Flight time limitations: Other commercial flying: airplanes.
14 CFR § 121.519 Flight time limitations: Deadhead transportation: airplanes.
14 CFR § 121.521 Flight time limitations: Crew of two pilots and one additional airman as required.
14 CFR § 121.523 Flight time limitations: Crew of three or more pilots and additional airmen as required.
14 CFR § 121.525 Flight time limitations: Pilots serving in more than one kind of flight crew.
14 CFR § 121.527 Fatigue risk management system.
14 CFR § 121.531 Applicability.
14 CFR § 121.533 Responsibility for operational control: Domestic operations.
14 CFR § 121.535 Responsibility for operational control: Flag operations.
14 CFR § 121.537 Responsibility for operational control: Supplemental operations.
14 CFR § 121.538 Aircraft security.
14 CFR § 121.539 Operations notices.
14 CFR § 121.541 Operations schedules: Domestic and flag operations.
14 CFR § 121.542 Flight crewmember duties.
14 CFR § 121.543 Flight crewmembers at controls.
14 CFR § 121.544 Pilot monitoring.
14 CFR § 121.545 Manipulation of controls.
14 CFR § 121.547 Admission to flight deck.
14 CFR § 121.548 Aviation safety inspector's credentials: Admission to pilot's compartment.
14 CFR § 121.548a DOD Commercial Air Carrier Evaluator's Credential.
14 CFR § 121.549 Flying equipment.
14 CFR § 121.550 Secret Service Agents: Admission to flight deck.
14 CFR § 121.551 Restriction or suspension of operation: Domestic and flag operations.
14 CFR § 121.553 Restriction or suspension of operation: Supplemental operations.
14 CFR § 121.555 Compliance with approved routes and limitations: Domestic and flag operations.
14 CFR § 121.557 Emergencies: Domestic and flag operations.
14 CFR § 121.559 Emergencies: Supplemental operations.
14 CFR § 121.561 Reporting potentially hazardous meteorological conditions and irregularities of ground facilities or navigation aids.
14 CFR § 121.563 Reporting mechanical irregularities.
14 CFR § 121.565 Engine inoperative: Landing; reporting.
14 CFR § 121.567 Instrument approach procedures and IFR landing minimums.
14 CFR § 121.569 Equipment interchange: Domestic and flag operations.
14 CFR § 121.570 Airplane evacuation capability.
14 CFR § 121.571 Briefing passengers before takeoff.
14 CFR § 121.573 Briefing passengers: Extended overwater operations.
14 CFR § 121.574 Oxygen and portable oxygen concentrators for medical use by passengers.
14 CFR § 121.575 Alcoholic beverages.
14 CFR § 121.576 Retention of items of mass in passenger and crew compartments.
14 CFR § 121.577 Stowage of food, beverage, and passenger service equipment during airplane movement on the surface, takeoff, and landing.
14 CFR § 121.578 Cabin ozone concentration.
14 CFR § 121.579 Minimum altitudes for use of autopilot.
14 CFR § 121.580 Prohibition on interference with crewmembers.
14 CFR § 121.581 Observer's seat: En route inspections.
14 CFR § 121.582 Means to discreetly notify a flightcrew.
14 CFR § 121.583 Carriage of persons without compliance with the passenger-carrying requirements of this part.
14 CFR § 121.584 Requirement to view the area outside the flightdeck door.
14 CFR § 121.585 Exit seating.
14 CFR § 121.586 Authority to refuse transportation.
14 CFR § 121.587 Closing and locking of flightcrew compartment door.
14 CFR § 121.589 Carry-on baggage.
14 CFR § 121.590 Use of certificated land airports in the United States.
14 CFR § 121.591 Applicability.
14 CFR § 121.593 Dispatching authority: Domestic operations.
14 CFR § 121.595 Dispatching authority: Flag operations.
14 CFR § 121.597 Flight release authority: Supplemental operations.
14 CFR § 121.599 Familiarity with weather conditions.
14 CFR § 121.601 Aircraft dispatcher information to pilot in command: Domestic and flag operations.
14 CFR § 121.603 Facilities and services: Supplemental operations.
14 CFR § 121.605 Airplane equipment.
14 CFR § 121.607 Communication and navigation facilities: Domestic and flag operations.
14 CFR § 121.609 Communication and navigation facilities: Supplemental operations.
14 CFR § 121.611 Dispatch or flight release under VFR.

14 CFR Part 121 — Operating Requirements: Domestic, Flag, and Supplemental Operations

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