FAR 91.818 — Supersonic Flight Authorization
FAR 91.818 explains how civil operators apply for FAA authorization to fly faster than Mach 1, including required info, environmental review, and limits.
In Plain English
FAR 91.818 governs how a civil operator can legally exceed Mach 1 (the speed of sound). Because supersonic flight produces sonic boom overpressure that can affect people and the environment on the ground, you can't just push the throttles up — you need a special flight authorization from the FAA Office of Environment and Energy.
The application must include detailed operational information:
- Operator name and aircraft make/model
- Number of flights, date range, and time of day
- A described flight area with supporting environmental information
- Conditions and limitations ensuring no measurable sonic boom reaches the surface outside that area
- Why the supersonic flight is necessary, and why it can't be safely conducted over the ocean instead
Authorizations are only granted for limited purposes such as showing airworthiness compliance, studying sonic boom characteristics, developing boom-reduction techniques, or measuring noise. The Administrator must also complete an environmental review under NEPA before issuing approval, and may terminate, suspend, or amend the authorization at any time to protect the environment. Operationally, this rule means supersonic civil flight in the U.S. is the exception, not the norm — and is tightly tied to test, research, and certification activity.
Regulation Text
14 CFR § 91.818§ 91.818 Special flight authorization to exceed Mach 1.
For all civil aircraft, any operation that exceeds Mach 1 may be conducted only in accordance with a special flight authorization issued to an operator in accordance with the requirements of this section.
(a)Application for a special flight authorization to exceed Mach 1 must be made to the FAA Office of Environment and Energy for consideration by the Administrator. Each application must include:
(1) The name of the operator;
(2) The number and model(s) of the aircraft to be operated;
(3) The number of proposed flights;
(4) The date range during which the flight(s) would be conducted;
(5) The time of day the flight(s) would be conducted. Proposed night operations may require further justification for their necessity;
(6) A description of the flight area requested by the applicant, including any environmental information required to be submitted pursuant to paragraph (c) of this section;
(7) All conditions and limitations on the flight(s) that will ensure that no measurable sonic boom overpressure will reach the surface outside of the proposed flight area; and
(8) The reason(s) that operation at a speed greater than Mach 1 is necessary. A special flight authorization to exceed Mach 1 may be granted only for operations that are intended to:
(i) Show compliance with airworthiness requirements;
(ii) Determine the sonic boom characteristics of an aircraft;
(iii) Establish a means of reducing or eliminating the effects of sonic boom, including flight profiles and special features of an aircraft;
(iv) Demonstrate the conditions and limitations under which speeds in excess of Mach 1 will not cause a measurable sonic boom overpressure to reach the surface; or
(v) Measure the noise characteristics of an aircraft to demonstrate compliance with noise requirements imposed under this chapter, or to determine the limits for operation in accordance with § 91.817(b).
(9) For any purpose listed in paragraph (a)(8) of this section, each applicant must indicate why its intended operation cannot be safely or properly accomplished over the ocean at a distance ensuring that no sonic boom overpressure reaches any land surface in the United States.
(b)An applicant may apply for an authorization to conduct flights outside a test area under certain conditions and limitations upon a conservative showing that:
(1) Flight(s) within a test area have been conducted in accordance with an authorization issued for the purpose specified in paragraph (a)(8)(iv) of this section;
(2) The results of the flight test(s) required by paragraph (b)(1) of this section demonstrate that a speed in excess of Mach 1 does not cause a measurable sonic boom overpressure to reach the surface; and
(3) The conditions and limitations determined by the test(s) represent all foreseeable operating conditions and are effective on all flights conducted under an authorization.
(c)(1) No special flight authorization will be granted if the Administrator finds that such action is necessary to protect or enhance the environment.
(2) The Administrator is required to consider the potential environmental impacts resulting from the issuance of an authorization for a particular flight area pursuant to the National Environmental Policy Act of 1969 (NEPA) (42 U.S.C 4321), all applicable regulations implementing NEPA, and related Executive orders and guidance. Accordingly, each applicant must provide information that sufficiently describes the potential environmental impact of any flight in excess of Mach 1, including the effect of a sonic boom reaching the surface in the proposed flight area, to enable the FAA to determine whether such impacts are significant within the meaning of NEPA.
(d)An authorization to operate a civil aircraft in excess of Mach 1 may be issued only after an applicant has submitted the information described in this section and the Administrator has taken the required action regarding the environmental findings described in paragraph (c) of this section.
(e)(1) An authorization to exceed Mach 1 will be granted for the time the Administrator determines necessary to conduct the flights for the described purposes.
(2) An authorization to exceed Mach 1 is effective until it expires or is surrendered.
(3) An authorization to exceed Mach 1 may be terminated, suspended, or amended by the Administrator at any time the Administrator finds that such action is necessary to protect the environment.
(4) The holder of an authorization to exceed Mach 1 may request reconsideration of a termination, amendment, or suspension issued under paragraph (e)(3) of this section within 30 days of notice of the action. Failure to request reconsideration and provide information why the Administrator's action is not appropriate will result in permanent termination of the authorization.
(5) Findings made by and actions taken by the Administrator under this section do not affect any certificate issued under chapter 447 of Title 49 of the United States Code.
[Docket FAA-2019-0451, Amdt. 91-362, 86 FR 3792, Jan. 15, 2021]
Oral Exam Questions a DPE Might Ask
Q1Can a civil operator legally fly faster than Mach 1 in the United States?
Only with a special flight authorization issued by the Administrator under FAR 91.818; without that authorization, civil operations exceeding Mach 1 are prohibited.
Q2What are some of the purposes for which the FAA may grant a Mach 1 authorization?
Per FAR 91.818(a)(8), authorizations may be issued to show airworthiness compliance, determine sonic boom characteristics, develop ways to reduce or eliminate sonic boom, demonstrate conditions where no measurable boom reaches the surface, or measure noise characteristics.
Q3What environmental considerations must the FAA address before issuing a supersonic authorization?
Under FAR 91.818(c), the Administrator must consider potential environmental impacts pursuant to NEPA, and the applicant must provide enough information about sonic boom and other impacts for the FAA to evaluate significance; no authorization is granted if denial is needed to protect the environment.
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Related Sections in Part 91