Civil aircraft sonic boom

This regulation prohibits civil aircraft from flying faster than Mach 1 (the speed of sound) over the United States unless the operator has special FAA authorization under § 91.818.

Additionally, if you're operating a civil aircraft capable of exceeding Mach 1 (even if you don't plan to go supersonic), you must have flight limitations available to the crew that prevent sonic booms from reaching the ground in U.S. territory during arrivals and departures. You must either follow these limitations or have the special authorization mentioned above.

In practice, this means supersonic flight over the U.S. is generally prohibited for civil aircraft due to the sonic boom disturbance. Even supersonic-capable aircraft flying to or from U.S. airports must carefully manage their speed profiles to ensure they only go supersonic over international waters or other countries' airspace where permitted, keeping sonic booms away from U.S. soil.

*This is a plain-English summary for study only. The official 14 CFR text on this page is controlling — always read the current regulation and consult a CFI.*