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.