Safety belts: passenger warning device.
CFR · 2024-01-01 · US · Title 14
(a) If there are means to indicate to the passengers when safety belts should be fastened, they must be installed to be operated from either pilot seat. (b) Each safety belt must be equipped with a metal to metal latching device.
official document · source cfr-2024 · id 14:§ 29.1413