All Parts Part 91 Subpart G—Additional Equipment and Operating Requirements for Large and Transport Category Aircraft § 91.603
§ 91.603

Aural speed warning device

No person may operate a transport category airplane in air commerce unless that airplane is equipped with an aural speed warning device that complies with § 25.1303(c)(1).

Sourced from eCFR · Title 14 CFR · for educational reference only — fly the latest regs.