---
kind: "section"
citation: "14 C.F.R. § 25.373"
title: "14"
number: "25.373"
heading: "Speed control devices."
url: "https://uscodex.org/cfr/14/25.373"
---

# §25.373. Speed control devices.


If speed control devices (such as spoilers and drag flaps) are installed for use in en route conditions—

- (a) The airplane must be designed for the symmetrical maneuvers prescribed in §§ [25.333](/cfr/14/25.333.md) and [25.337](/cfr/14/25.337.md), the yawing maneuvers in [§ 25.351](/cfr/14/25.351.md), and the vertical and lateral gust and turbulence conditions prescribed in § [25.341(a)](/cfr/14/25.341.md?p=a) and [(b)](/cfr/14/25.341.md?p=b) at each setting and the maximum speed associated with that setting; and
- (b) If the device has automatic operating or load limiting features, the airplane must be designed for the maneuver and gust conditions prescribed in [paragraph (a)](#a) of this section, at the speeds and corresponding device positions that the mechanism allows.

## Notes

### Amendments

[Doc. No. 5066, 29 FR 18291, Dec. 24, 1964, as amended by Amdt. 25-72, 55 FR 29776, July 20, 1990; Amdt. 25-86, 61 FR 5222, Feb. 9, 1996; Amdt. 25-141, 79 FR 73468, Dec. 11, 2014]

### 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

[Doc. No. 5066, 29 FR 18291, Dec. 24, 1964, as amended by Amdt. 25-72, 55 FR 29776, July 20, 1990; Amdt. 25-86, 61 FR 5222, Feb. 9, 1996; Amdt. 25-141, 79 FR 73468, Dec. 11, 2014]