Aviation Safety Oversight: Who Is Responsible for What

Who Holds Responsibility

No single organization is responsible for the safety of a commercial flight. Federal regulations divide the duties of aviation safety oversight and operation among the airline or cargo carrier that operates the flight, the manufacturers that designed the aircraft and its parts, the repair stations that maintain it, the pilot in command, the airport, and the Federal Aviation Administration (FAA), which prescribes minimum safety standards and certifies the others. The National Transportation Safety Board (NTSB) investigates accidents but does not regulate the industry.

The concept that sorts out who answers for what is operational control. 14 CFR 1.1 defines it as “the exercise of authority over initiating, conducting or terminating a flight.” Federal regulations assign that authority to the certificate holder that operates the flight.

The table summarizes each organization’s main duties, the federal laws and regulations that set them, and the records or documents each one generates.

Air Carriers and Operational Control

A company that sells air transportation to the public needs an air carrier operating certificate, which the FAA issues only after finding the company properly equipped and able to operate safely. Under 14 CFR 119.5, a direct air carrier, meaning a company that controls the operational functions of the transportation it provides, receives an Air Carrier Certificate. The holder then flies under Part 121 or Part 135 depending on its aircraft and type of service, and sorts operators into those two parts by seats, payload, and schedule.

Both parts place operational control on the certificate holder. Under Part 121, each holder conducting domestic, flag, or supplemental operations is responsible for operational control (121.533, 121.535, 121.537), and under Part 135 each holder is responsible for operational control and must list in its manual the name and title of each person it authorizes to exercise it.

Inside a Part 121 airline conducting domestic or flag operations, the duties are shared. The pilot in command and the aircraft dispatcher are jointly responsible for preflight planning, delay, and the dispatch release. The dispatcher monitors each flight’s progress and may cancel or redispatch a flight if the dispatcher or the pilot concludes it cannot operate or continue safely as planned.

Cargo Carriers and Integrated Airlines

Cargo flights use the same certification structure as passenger flights. An all-cargo operation is any operation for compensation or hire that is other than a passenger-carrying operation, with limited exceptions. All-cargo operations with airplanes that have a payload capacity above 7,500 pounds are supplemental operations, which Part 121 governs, while all-cargo operations with airplanes at or below that payload are on-demand operations under Part 135 (14 CFR 119.21).

Integrated express carriers, which include FedEx, UPS, and DHL, operate scheduled aircraft, trucks, and couriers for door-to-door delivery. Because the airline within such a company is a certificate holder, the duties described in this article apply to it. A November 2025 UPS flight now under NTSB investigation, for example, was a cargo flight operating under Part 121.

Maintenance and Contracted Work

Airlines may hire others to maintain their aircraft, but the responsibility stays with the airline. Under 14 CFR 121.363, a certificate holder is primarily responsible for the airworthiness of its aircraft, which an FAA airworthiness approval describes as conformity to the approved design and a condition for safe operation, and for the performance of maintenance under its manual. It may arrange for another person to do the work, but that arrangement does not relieve it of the responsibility. 14 CFR 135.413 sets the same primary responsibility for Part 135 holders.

Much contracted work is done by repair stations certificated under 14 CFR Part 145. A repair station may perform maintenance and alterations only on articles it is rated for and within its operations specifications, and it may approve those articles for return to service. It must keep a quality control system, report serious failures, malfunctions, or defects to the FAA within 96 hours, and retain records for two years from the date an article returns to service, available for inspection by the FAA and the NTSB.

Before an airline operates an aircraft after maintenance, the airline or the person it arranged for the work must prepare an airworthiness release or log entry certifying that the work followed the airline’s manual and that no known condition makes the airplane unairworthy. Each airline must also keep maintenance records showing, among other items, the total time in service of the airframe, the status of life-limited parts, and the current status of applicable airworthiness directives.

Manufacturers and Component Suppliers

Manufacturers are regulated through design and production approvals under 14 CFR Part 21. The FAA issues a type certificate, its approval of a product’s design, when the applicant shows that the aircraft, engine, or propeller meets the applicable airworthiness and other requirements. For transport category airplanes, the design standards are in 14 CFR Part 25.

Suppliers of parts and equipment need approvals of their own. An applicant for a parts manufacturer approval must show that the article’s design meets the airworthiness requirements, and a technical standard order authorization is an FAA design and production approval for an article that meets a specific technical standard order, which is a minimum performance standard.

The duties continue after delivery. The holder of a design approval must furnish Instructions for Continued Airworthiness to the owner of each aircraft, engine, or propeller, and when an airworthiness directive calls for design changes the type certificate holder must, on the FAA’s request, submit design changes for approval and make the approved data available to all operators.

Holders of type certificates, parts manufacturer approvals, and technical standard order authorizations must also report certain failures, malfunctions, and defects, including engine failures, fires caused by system failures, and flight control malfunctions that interfere with normal control. The report is due within 24 hours after the holder determines that a reportable occurrence has happened. When the FAA finds an unsafe condition that is likely to exist in other products of the same type design, it can issue an airworthiness directive, which is a legally enforceable rule.

Pilots and Crew Authority

The pilot in command is the person with final authority and responsibility for the operation and safety of a flight. Under 14 CFR 91.3, which is part of the general operating rules, the pilot in command is directly responsible for, and is the final authority as to, the operation of the aircraft. In an in-flight emergency requiring immediate action, the pilot may deviate from any rule of Part 91 to the extent required and must send a written report of the deviation if the FAA asks for one.

Part 121 adds that the pilot in command is responsible for the safety of the passengers, crewmembers, cargo, and airplane, and has full control and authority over the other crewmembers during flight time. Pilots must also document their training and flight experience in a pilot logbook.

The FAA as Certifying Authority

By statute, the FAA Administrator must promote safe flight by prescribing minimum standards for aircraft design and construction, regulations and standards for inspection and overhaul, and regulations on the maximum hours of service of airmen and other air carrier employees. The FAA issues the certificates that let others operate, and it may delegate examination, testing, and inspection to qualified private persons under its supervision, a delegation it can rescind at any time.

A safety management system is a formal, top-down, organization-wide approach to managing safety risk and assuring that risk controls work. 14 CFR Part 5 applies to holders of Part 121 and Part 135 certificates, air tour operators with a Letter of Authorization under 14 CFR 91.147, and certain holders of type and production certificates. The FAA’s final rule, published April 26, 2024 and effective May 28, 2024, expanded safety management system requirements beyond Part 121 airlines.

The compliance dates differ by group. Part 121 holders with an existing safety management system had to revise it by May 28, 2025. Part 135 and air tour operators must implement a safety management system and submit a declaration of compliance by May 28, 2027. Type and production certificate holders had to submit an implementation plan by November 28, 2024 and must implement the system by May 28, 2027. A safety management system must be appropriate to the size, scope, and complexity of the organization, and it is not a substitute for compliance with other federal regulations.

Air Traffic Control and Airports

Air traffic control is an FAA function. The FAA’s Air Traffic Organization is the operational arm of the FAA, responsible for air navigation services across 29.4 million square miles of airspace. Federal regulations define air traffic control as a service operated by appropriate authority to promote the safe, orderly, and expeditious flow of air traffic, and an air traffic clearance as an authorization from air traffic control for an aircraft to proceed under specified traffic conditions in controlled airspace.

Airports are certificated separately. Under 14 CFR Part 139, an airport serving scheduled passenger operations of air carrier aircraft with more than 9 passenger seats, or unscheduled operations with at least 31 seats, must hold an Airport Operating Certificate and adopt and comply with an Airport Certification Manual. Certificate holders keep records such as personnel training, self-inspections, and accidents and incidents in movement areas for set periods.

Owners, Lessors, and Operational Control

Owning an aircraft and operating it are different things under federal regulations. The owner or operator of an aircraft is primarily responsible for maintaining it in an airworthy condition under Part 91. For a lease of a U.S.-registered large civil aircraft, the parties must include a truth-in-leasing clause that identifies the person responsible for operational control, and the requirement does not apply to every lease, for example not when the lessee is a Part 121 certificate holder.

When a certificate holder leases an aircraft to another person engaged in common carriage, the FAA determines which party has operational control and amends the operations specifications of each party as needed.

Federal law also limits when a lessor, owner, or secured party can be liable. Under 49 U.S.C. 44112(b), such a person is liable for personal injury, death, or property loss or damage only when the aircraft, engine, or propeller is in that person’s actual possession or operational control and the harm occurs because of the aircraft, engine, or propeller, or because of the flight of, or an object falling from, it. The statute defines a lessor as a person leasing for at least 30 days. The limit follows the line the regulations draw: responsibility attaches to whoever exercises operational control. Which defendants can be liable in a particular accident depends on facts beyond this structure, and the rules on who can be liable after an aviation accident are a separate subject.

The NTSB Investigates Without Regulating

The NTSB is an independent federal agency charged by Congress with investigating every civil aviation accident in the United States, determining probable cause, and issuing safety recommendations. The statute directs it to establish the facts, circumstances, and cause or probable cause of aircraft accidents. It has no authority to require implementation of its recommendations.

When the NTSB sends a recommendation to the Secretary of Transportation, federal law requires a formal written response within 90 days stating whether the Secretary intends to adopt all of it, part of it, or none of it. A response that adopts must include a timetable, and a refusal must include reasons. The duty is to answer, not to adopt.

The NTSB brings the other organizations into an investigation as parties, one step in the NTSB investigation process. Party status is limited to those whose employees, functions, activities, or products were involved in the accident and who can provide qualified technical personnel, and apart from the FAA no entity has a right to participate. In the investigation of the November 4, 2025 accident of UPS flight 2976, the NTSB invited the FAA, UPS, Boeing, GE Aerospace, Collins Aerospace, and two labor organizations. That investigation is still ongoing, and the NTSB describes its published information as preliminary and subject to change.

Party status is not a finding about the party. A probable cause determination is an investigative conclusion, and federal regulations bar use of a Board accident report in any suit or action for damages growing out of a matter it mentions. Whether an organization is legally responsible for an accident is decided separately, and the duties described above are only one input to that question.