---
kind: "section"
citation: "14 C.F.R. § 25.1505"
title: "14"
number: "25.1505"
heading: "Maximum operating limit speed."
url: "https://uscodex.org/cfr/14/25.1505"
---

# §25.1505. Maximum operating limit speed.


The maximum operating limit speed (VMO/MMO airspeed or Mach Number, whichever is critical at a particular altitude) is a speed that may not be deliberately exceeded in any regime of flight (climb, cruise, or descent), unless a higher speed is authorized for flight test or pilot training operations. VMO/MMO must be established so that it is not greater than the design cruising speed VC and so that it is sufficiently below VD/MD or VDF/MDF, to make it highly improbable that the latter speeds will be inadvertently exceeded in operations. The speed margin between VMO/MMO and VD/MD or VDFM/DF may not be less than that determined under [§ 25.335(b)](/cfr/14/25.335.md?p=b) or found necessary during the flight tests conducted under [§ 25.253](/cfr/14/25.253.md).


## Notes

### Amendments

[Amdt. 25-23, 35 FR 5680, Apr. 8, 1970]

### 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. 25-23, 35 FR 5680, Apr. 8, 1970]