14 C.F.R. § 25.1549 Powerplant and auxiliary power unit instruments.
Title 14 - Aeronautics and Space
For each required powerplant and auxiliary power unit instrument, as appropriate to the type of instrument— (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 speed range that is restricted because of excessive vibration stresses must be marked with red arcs or red lines. [Amdt. 25–40, 42 FR 15044, Mar. 17, 1977]
Title 14: Aeronautics and Space
PART 25—AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES
Subpart G—Operating Limitations and Information
Markings and Placards
§ 25.1549 Powerplant and auxiliary power unit instruments.
