14 C.F.R. § 25.1322 Warning, caution, and advisory lights.
Title 14 - Aeronautics and Space
If warning, caution or advisory lights are installed in the cockpit, they must, unless otherwise approved by the Administrator, be— (a) Red, for warning lights (lights indicating a hazard which may require immediate corrective action); (b) Amber, for caution lights (lights indicating the possible need for future corrective action); (c) Green, for safe operation lights; and (d) Any other color, including white, for lights not described in paragraphs (a) through (c) of this section, provided the color differs sufficiently from the colors prescribed in paragraphs (a) through (c) of this section to avoid possible confusion. [Amdt. 25–38, 41 FR 55467, Dec. 20, 1976]
Title 14: Aeronautics and Space
PART 25—AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES
Subpart F—Equipment
Instruments: Installation
§ 25.1322 Warning, caution, and advisory lights.