(a) Each maximum and, if applicable, minimum safe operating limit must be marked with a red radial or a red line;
(b) Each normal operating range must be marked with a green arc or green line, not extending beyond the maximum and minimum safe limits;
(c) Each takeoff and precautionary range must be marked with a yellow arc or a yellow line; and
(d) Each engine, auxiliary power unit, or propeller range that is restricted because of excessive vibration stresses must be marked with red arcs or red lines.
[Amdt. 23–12, 41 FR 55466, Dec. 20, 1976, as amended by Amdt. 23–28, 47 FR 13315, Mar. 29, 1982; Amdt. 23–45, 58 FR 42166, Aug. 6, 1993]