---
kind: "section"
citation: "14 C.F.R. § 25.1517"
title: "14"
number: "25.1517"
heading: "Rough air speed, V RA."
url: "https://uscodex.org/cfr/14/25.1517"
---

# §25.1517. Rough air speed, V RA.

- (a) A rough air speed, VRA, for use as the recommended turbulence penetration airspeed, and a rough air Mach number, MRA, for use as the recommended turbulence penetration Mach number, must be established. VRA/MRA must be sufficiently less than VMO/MMO to ensure that likely speed variation during rough air encounters will not cause the overspeed warning to operate too frequently.
- (b) At altitudes where VMO is not limited by Mach number, in the absence of a rational investigation substantiating the use of other values, VRA must be less than VMO minus 35 KTAS.
- (c) At altitudes where VMO is limited by Mach number, MRA may be chosen to provide an optimum margin between low and high speed buffet boundaries.

## Notes

### Amendments

[Amdt. 25-141, 79 FR 73469, Dec. 11, 2014, as amended by FAA-2022-1355; Amdt. No. 25-148, 87 FR 75710, Dec. 9, 2022; 88 FR 2813, Jan. 18, 2023]

### Authority

Authority: 49 U.S.C. 106(f), 106(g), 40113, 44701, 44702 and 44704; Pub. L. 115-254, 132 Stat 3281 (49 U.S.C. 44903 note).

### Source

Source: Docket No. 5066, 29 FR 18291, Dec. 24, 1964, unless otherwise noted.

### Amendments

[Amdt. 25-141, 79 FR 73469, Dec. 11, 2014, as amended by FAA-2022-1355; Amdt. No. 25-148, 87 FR 75710, Dec. 9, 2022; 88 FR 2813, Jan. 18, 2023]