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Outline of the Federal Aviation Regulations, Pilot Requirements, and Aircraft Requirements





This page helps you get an understanding of the different certifications.

Basic Types of Civil Aircraft Operations

The operator should contact the nearest FAA Flight Standards district office (FSDO) for assistance and guidance in bringing its operations into compliance with the FAR. For operations requiring certification, the FSDO manager will assign an FAA aviation safety inspector to assist the operator during the certification process. Initial inquiries about certification or requests for applications should be in writing or by personal visit to the FSDO.



(1) FAR Part 91 prescribes the general flight rules for all aircraft operations within the United States, including the waters within 3 nautical miles of the U.S. coast. U.S.-registered civil aircraft are required to comply with FAR Part 91. When over the high seas, they must comply with Annex 2 (Rules of the Air) to the Convention on International Civil Aviation.

(2) FAR Part 91 prohibits a pilot from operating a civil aircraft unless it is in an airworthy condition. The pilot in command (PIC) is responsible for determining whether the aircraft is in condition for safe flight. The PIC is required to terminate the flight when unairworthy mechanical, electrical, or structural conditions occur. In addition, the PIC may not operate the aircraft without complying with the operating limitations specified in the approved Airplane or Rotorcraft Flight Manual, markings, and placards, or as otherwise prescribed by the certificating authority of the country of registry.

(3) Under FAR Part 91, the PIC of an aircraft is directly responsible for, and is the final authority as to the operation of that aircraft. In case of an inflight emergency, the PIC is authorized to deviate from any rule in FAR Part 91 to the extent necessary to meet the emergency. However, any PIC who deviates from a rule in FAR Part 91 is required, upon the request of the Administrator, to send a written report of that deviation to the Administrator.



FAR Part 125. If an operator uses an airplane with a seating configuration for 20 or more passenger seats or a maximum payload capacity of 6,000 pounds or more, and is not engaged in "common carriage," then FAR Part 125 applies. A person is considered to be engaged in "common carriage" when "holding out" to the general public or to a segment of the public as willing to furnish transportation within the limits of its facilities to any person who wants it. Examples of holding out are as follows: advertising through telephone yellow pages, billboards, television, radio, and individual ticketing. FAR Section 125.11(b) prohibits FAR Part 125 certificate holders from conducting any operation which results directly or indirectly from holding out to the general public. Further information regarding common carriage vs. private carriage can be found in AC 120-12. If the operator is engaged in "common carriage," then FAR Part 121 or 135 applies rather than FAR Part 125.


FAR PART 121 or 135

When a aircraft is operated "for commercial purposes", the requirements contained in either FAR Part 121 or 135, depending on the type of operation, must be met. Generally, FAR Part 121 applies to domestic, flag, and supplemental air carriers and commercial operators of large aircraft, while FAR Part 135 applies to air taxi operators and commercial operators. An operator should consult Special Federal Aviation Regulation (SFAR) No. 38-2 as well as the applicability provisions of each part (FAR Sections 121.1 and 135.1) to determine whether it is FAR Part 121 or 135 that applies to a particular operation. The FSDO will provide an applicant for a FAR Part 121 or 135 certificate with a videotape on certification and a copy of AC 120-49, Certification of Air Carriers. Once the videotape and the AC have been reviewed, the applicant will complete FAA Form 8400-6, Preapplication Statement of Intent, and the FSDO manager will assign a Certification Team to assist the applicant through each phase of the certification process.



FAR Part 133, Rotorcraft External-Load Operations, prescribes the airworthiness certification requirements for rotorcraft, and the operating and certification rules governing the operation of rotorcraft conducting external-load operations in the United States by any person. The certification rules do not apply to a Federal, state, or local government conducting operations with a government-owned aircraft unless it is operating as a civil aircraft due to receipt of compensation. Federal, state, or local governments must; however, comply with all of the other rules contained in FAR Part 133, even when operating a public aircraft.

(1) FAR Part 133 requires that a person must obtain a Rotorcraft External-Load Operator Certificate issued by the FAA before any rotorcraft external-load operations in the United States are begun. This certificate is valid for 24-calendar months unless it is surrendered, suspended, or revoked prior to the expiration date shown on the certificate.

(2) Rotorcraft used in external-load operations must have been type certificated and must continue to meet the requirements of FAR Part 27 or 29 or of FAR Section 21.25. Rotorcraft must also comply with the airworthiness requirements contained in Subpart D of FAR Part 133 and must have a valid standard or restricted category airworthiness certificate. At the present time, only rotorcraft of U.S. registry are eligible for external-load operations.

(3) Pilots conducting rotorcraft external-load operations must have at least a current commercial pilot certificate with a rating appropriate to the rotorcraft being used, and a Second Class Medical Certificate.



FAR Part 137, Agricultural Aircraft Operations, prescribes the rules which govern the certification and operation of agricultural aircraft operated in the United States, and the issuance of either a private or commercial agricultural aircraft operator certificate for those operations. In a public emergency, a person who conducts agricultural aircraft operations may, where necessary, deviate from any operating rule contained in FAR Part 137 for relief and welfare activities approved by an agency of the United States or of a state or local government. However, each person who deviates from a rule shall complete a report of the aircraft operation involved within 10 days, including a description of the operation and the reasons for it, to the nearest FAA FSDO.

(1) As defined in FAR Part 137, an agricultural aircraft operation means the operation of an aircraft for the purpose of:

(i) dispensing any economic poison;

(ii) dispensing any other substance intended for plant nourishment, soil treatment, propagation of plant life, or pest control; or

(iii) engaging in dispensing activities directly affecting agriculture, horticulture, or forest preservation. It does not include the dispensing of live insects. Forest firefighting is considered to be an agricultural aircraft operation.

(2) FAR Part 137 requires that a person must obtain an Agricultural Aircraft Operator Certificate issued by the FAA before any agricultural aircraft operations in the United States are begun. A rotorcraft may conduct agricultural aircraft operations with external dispensing equipment in place without a rotorcraft external-load operator certificate. However, an operator with a rotorcraft external-load operator certificate may conduct agricultural aircraft operations if it disperses only water on forest fires by rotorcraft external-load means without an agricultural aircraft operator certificate. A Federal, state, or local government conducting agricultural aircraft operations is not required to obtain an Agricultural Aircraft Operator Certificate. They must; however, comply with all of the other rules contained in FAR Part 137.

(3) Aircraft used in agricultural aircraft operations must be certificated and airworthy, and equipped for agricultural operation. They must be equipped with a suitable and properly installed shoulder harness for use by each pilot.

(4) Operators conducting agricultural aircraft operations must have the services of one person who has at least a current U.S. commercial pilot certificate and who is properly rated for the aircraft to be used.



a. Generally. All civil aircraft are required to be operated by pilots certificated under FAR Part 61, Certification: Pilots And Flight Instructors. FAR Part 61 prescribes the requirements for issuing pilot certificates and ratings, the conditions under which those certificates and ratings are necessary, and the privileges and limitations of those certificates and ratings.

b. Domestic Aircraft. Pilots operating civil aircraft of U.S. registry are required to have in their personal possession a current pilot certificate issued to them under FAR Part 61. U.S.-registered aircraft may be operated in a foreign country with a pilot license issued by that country.

c. Foreign Aircraft. Foreign aircraft may be operated in the U.S. by pilots who have in their personal possession current pilot certificates issued under FAR Part 61 or a pilot license issued to them or validated for them by the country in which the aircraft is registered.

d. Medical Certificate. Pilots operating U.S.-registered civil aircraft are required to have in their personal possession an appropriate current medical certificate issued to them under FAR Part 67, Medical Standards and Certification. FAR Part 67 prescribes the medical standards for issuing medical certificates. A Third Class Medical Certificate is required for Private Pilot certification. A Second Class Medical Certificate is required for Commercial Pilot certification. A First Class Medical Certificate is required for Airline Transport Pilot Certification.

e. Instrument Rating. Pilots operating civil aircraft under instrument flight rules or in weather conditions less than the minimums prescribed for Visual Flight Rules are required to hold an Instrument Rating or an Airline Transport Pilot Certificate appropriate for the aircraft flown.



a. Generally. Government aircraft operations that are no longer eligible for public aircraft status must now meet the civil airworthiness standards for certification of aircraft. This includes the aircraft's engines and propellers as well as the aircraft as a whole. A civil aircraft must have a current airworthiness certificate to operate in the National Airspace System. Additionally, all civil aircraft must meet the following requirements:

(1) The aircraft must have an effective U.S. registration certificate on board during all operations as required by FAR Section 91.203.

(2) An appropriate and current airworthiness certificate must be displayed in accordance with FAR Section 91.203(c). An airworthiness certificate is effective as long as the maintenance, preventative maintenance, and alterations are performed in accordance with FAR Parts 21, 43, and 91, as appropriate, and the aircraft is registered in the United States.

(3) The aircraft must have been inspected in accordance with FAR Section 91.409 within the preceding 12-calendar months.

(i) If the government agency plans to use a progressive inspection program, it must submit a written request to the FAA. The request must be sent to the FSDO having jurisdiction over the area in which the applicant is located and the applicant must be able to meet the requirements identified in FAR Section 91.409(d).

(ii) Large airplanes, turbojet multiengine airplanes, turbopropeller-powered multiengine airplanes, and turbine-powered rotorcraft must have a program approved that meets the requirements of FAR Section 91.409(e).

(4) All maintenance and required inspections must have been completed by a person authorized under FAR Sections 43.3 and 43.7. Additionally, the maintenance and inspections performed must be recorded in accordance with FAR Sections 43.9 and 43.11. FAR Part 43 prescribes the rules governing the maintenance, preventative maintenance, rebuilding, and alteration of civil U.S.-registered aircraft.

(5) Any alterations to the aircraft must have been accomplished and returned to service by an appropriately certified and authorized person under FAR Part 43.

(6) Aircraft operations for compensation or hire must be performed in accordance with the appropriate Air Operations Certificate, e.g., FAR Part 125, 135, etc.

b. Type Certification. Prior to airworthiness certification, the type design must be certificated by the FAA. Section 603(c) of the Federal Aviation Act of 1958 makes a type certificate a prerequisite for issuance of airworthiness certificates. Each government operator who wishes to determine the eligibility of its aircraft for civil operations must contact the responsible geographic Aircraft Certification Office (ACO) for assistance in seeking either:

(1) design approval for aircraft that have been type certificated in the past; or

(2) type certification approval of aircraft that have been operated in the past under public aircraft status without a type certificate.

c. Aircraft Previously Type Certificated. If the aircraft was originally built to an FAA type certificate, the Aircraft Certification Office will review the type certificate data and make a comparison with the aircraft's current design and condition.

(1) The applicant should provide the FAA Aircraft Certification Office with the technical information to assist in the following:

(i) a review of type design for any engineering changes or modifications;

(ii) a review of replacement parts and technical data on the replacement parts;

(iii) a review of applicable Airworthiness Directives (AD);

(iv) a review of previous operating regimes;

(v) if needed, application of later regulatory amendments or special conditions for any changes found necessary to establish current airworthiness standards for safe design.

(2) The applicant must provide accurate records of any changes from the approved type design that are necessary to establish the current design. The applicant should update all maintenance manuals as necessary. If there has been a substantial change in the type design, e.g., in the configuration, power, power limitations, speed limitations, or weight that have proven so extensive that a substantially complete investigation of compliance with the applicable regulations is required, the owner will be required to apply for a new type certificate.

d. Aircraft with No Prior Certification. It may be difficult to obtain type certification of aircraft that have no history of civil certification. However, if a government operator wishes to apply for type certification, it should file an application for a type certificate on FAA Form 8110.12. The applicant must submit the application and all type design data for the aircraft, including the aircraft's engines and propellers, to the Aircraft Certification Office in its geographic area for approval. The application form must be accompanied by a three-view drawing and available basic data so that a preliminary regulatory certification basis may be established. The applicable airworthiness certification regulations, i.e., FAR Part 23, 25, 27, 29, 33, 35, etc., will be those that are in effect on the date of application for the certificate, unless otherwise noted in the regulations. The applicant must submit the type design, test reports, and computations necessary to show that the product to be certificated meets the applicable airworthiness, aircraft noise, fuel venting, and exhaust emission requirements of the FAR. Upon examining the data and test reports, participating in testing, and inspecting the prototype aircraft, the Administrator must be able to find that the type design in fact complies with the above-mentioned regulations.

e. Airworthiness Certification. An operator of an aircraft that has been operated in public aircraft status cannot obtain a standard airworthiness certificate or return the aircraft to civil operations without showing that the aircraft meets all the criteria for that airworthiness certificate as prescribed by the regulations. Making that showing may be difficult when the aircraft has not been maintained, altered, or inspected in accordance with the FAR. In order to receive a standard airworthiness certificate, the operator should show that the aircraft has been maintained according to the manufacturer's instructions, and that any modifications to the aircraft either were removed or approved by the FAA. Before a standard airworthiness certificate can be issued, the applicant must show that:

(1) The aircraft conforms to its approved type design and is in condition for safe operation.

(2) Any alterations were accomplished in accordance with an approved supplemental type certificate (STC) or other FAA approved data, such as a field approval as reflected by the issuance of an FAA Form 337, Major Repair or Alteration.

(3) All applicable AD's have been complied with.

(4) If altered while in another category, the aircraft continues to meet, or has been returned to, its approved type design configuration and is in a condition for safe operation.

f. Procedures for Obtaining Certificate. Applicants interested in obtaining an airworthiness certificate must follow the following procedures.

(1) Applicants are required to submit a properly executed Application for Airworthiness, FAA Form 8130-6, and any other documents called for in FAR Parts 21 and 45 for certification. An applicant may obtain an FAA Form 8130-6, "Application for Airworthiness" from the local Manufacturing Inspection district office (MIDO) or FSDO. The applicant must have completed and signed the appropriate sections prior to submitting it to the FAA.

(2) The applicant is required to make available for inspection and review the aircraft, aircraft records, and any other data necessary to establish conformity to its type design.

(3) The applicant must properly register the aircraft in accordance with FAR Part 47, Aircraft Registration.

(4) The applicant is also required to show that the aircraft complies with the noise standards of FAR Sections 21.93(b), 21.183(e), Part 36, or Part 91, as appropriate. This may be demonstrated through the use of data. Also, the applicant is required to show that the aircraft's fuel venting and exhaust emission systems comply with the requirements of FAR Part 34. In addition, the applicant must show the aircraft meets the applicable passenger emergency exit requirements of FAR Section 21.183(f) and SFAR No. 41.

(5) During the course of the certification process, the FAA will review records and documentation to the extent necessary to establish that:

(i) All of the required records and documentation are provided for the aircraft; i.e., an up-to-date approved flight manual, a current weight and balance report, equipment list, maintenance records, FAA-accepted Instructions for Continued Airworthiness (ICAW) and/or FAA-acceptance maintenance manual(s) (MM), and any other manuals required by FAR Sections 21.31, 21.50, 23.1529, 25.1529, 27.1529, 29.1529, 33.4, and 35.4. These documents must be in the English language.

(ii) The applicant should ensure that the appropriate markings are present in accordance with FAR Part 45. The applicant should make available the Type Certificate Data Sheets (TCDS), aircraft specification, or aircraft listing that is applicable.

(iii) The inspection records and technical data should reflect that the aircraft conforms to the type design, and all required inspections, including those provided for in FAR Section 21.183(d)(2), which provides for a 100-hour inspection, as described in FAR Section 43.15 and Appendix D. The applicant must also show that the tests the aircraft has been subjected to have been satisfactorily completed, the records completed, and reflect no unapproved design changes.

(iv) The aircraft has been flight tested, if required. If it has not been flight tested, the FAA may issue a special airworthiness certificate as provided for in FAR Sections 21.35 and 21.191(b). The flight test must be recorded in the aircraft records in accordance with FAR Section 91.417(a)(2)(i) as time in service as defined in FAR Part 1. Aircraft assembled by a person other than the manufacturer (e.g., a dealer or distributor) must have been assembled and, when applicable, flight tested in accordance with the manufacturer's FAA-approved procedures.

(v) Large airplanes, turbojet, cheap replica watches or turbopropeller multiengined airplanes must comply with the inspection program requirements of Subpart C of FAR Part 91 or other FAR referenced therein. A supplemental structural inspection program is also required for certain large transport category airplanes. Reference AC 91-56, Supplemental Structural Inspection Program for Large Transport Category Airplanes.

(6) Inspection of the aircraft. Aircraft submitted by the applicant for inspection will be inspected for the following:

(i) The nationality and registration marks and identification plate should be displayed and marked in accordance with FAR Part 45. The information presented should agree with the application for airworthiness certification.

(ii) All equipment, both required and optional, should be properly installed and listed in the aircraft equipment list.

(iii) Instruments and placards should be located in the appropriate places, installed, and properly marked in the English language.

(iv) All applicable AD's must have been complied with and appropriately recorded.

(v) The aircraft should conform to its approved U.S. type certificate and should be in a condition for safe operation.

(vi) All aircraft systems should have been satisfactorily checked for proper operation. The operation of the engine(s) and propeller(s) should be checked in accordance with the aircraft manufacturer's instructions.


Additional Aircraft Maintenance Requirments under Part 135

Part 135 operators are responsible for establishing methods acceptable to the Administrator for compliance with the additional maintenance requirements of Title 14 of the Code of Federal Regulations (14 CFR) part 135, § 135.421 for certain air carriers and commercial operators. Advisory Circular 135-7B provides information related to other regulatory maintenance requirements applicable to part 135 aircraft type certificated (TC) for nine or less passenger seats.