---
kind: "section"
citation: "14 C.F.R. § 27.1549"
title: "14"
number: "27.1549"
heading: "Powerplant instruments."
url: "https://uscodex.org/cfr/14/27.1549"
---

# §27.1549. Powerplant instruments.


For each required powerplant instrument, as appropriate to the type of instrument—

- (a) Each maximum and, if applicable, minimum safe operating limit must be marked with a red line;
- (b) Each normal operating range must be marked as a green or unmarked range;
- (c) Each takeoff and precautionary range must be marked with a yellow range or yellow line;
- (d) Each engine or rotor range that is restricted because of excessive vibration stresses must be marked with red ranges or red lines; and
- (e) Each OEI limit or approved operating range must be marked to be clearly differentiated from the markings of [paragraphs (a) through (d)](#a..d) of this section except that no marking is normally required for the 30-second OEI limit.

## Notes

### Amendments

[Amdt. 27-11, 41 FR 55470, Dec. 20, 1976, as amended by Amdt. 27-23, 53 FR 34215, Sept. 2, 1988; Amdt. 27-29, 59 FR 47768, Sept. 16, 1994; Amdt. 27-51, 88 FR 8738, Feb. 10, 2023]

### Authority

Authority: 49 U.S.C. 106(f), 106(g), 40113, 44701-44702, 44704.

### Source

Source: Docket No. 5074, 29 FR 15695, Nov. 24, 1964, unless otherwise noted.

### Amendments

[Amdt. 27-11, 41 FR 55470, Dec. 20, 1976, as amended by Amdt. 27-23, 53 FR 34215, Sept. 2, 1988; Amdt. 27-29, 59 FR 47768, Sept. 16, 1994; Amdt. 27-51, 88 FR 8738, Feb. 10, 2023]