14 CFR §91.821
Verified against eCFR.gov as of June 20, 2026View official text on eCFR.gov ↗
Except for Concorde airplanes having flight time before January 1, 1980, no person may operate in the United States, a civil supersonic airplane that does not comply with Stage 2 noise limits of part 36 in effect on October 13, 1977, using applicable trade-off provisions.