14 C.F.R. § 23.335 Design airspeeds.
Title 14 - Aeronautics and Space
Except as provided in paragraph (a)(4) of this section, the selected design airspeeds are equivalent airspeeds (EAS). (a) Design cruising speed, V (1) Where W/S′=wing loading at the design maximum takeoff weight, Vc (in knots) may not be less than— (i) 33 √(W/S) (for normal, utility, and commuter category airplanes); (ii) 36 √(W/S) (for acrobatic category airplanes). (2) For values of W/S more than 20, the multiplying factors may be decreased linearly with W/S to a value of 28.6 where W/S=100. (3) V (4) At altitudes where an M (b) Design dive speed V (1) V (2) With V (i) 1.40 V (ii) 1.50 V (iii) 1.55 V (3) For values of W/S more than 20, the multiplying factors in paragraph (b)(2) of this section may be decreased linearly with W/S to a value of 1.35 where W/S=100. (4) Compliance with paragraphs (b)(1) and (2) of this section need not be shown if V (i) The speed increase resulting when, from the initial condition of stabilized flight at V (ii) Mach 0.05 for normal, utility, and acrobatic category airplanes (at altitudes where MD is established); or (iii) Mach 0.07 for commuter category airplanes (at altitudes where MD is established) unless a rational analysis, including the effects of automatic systems, is used to determine a lower margin. If a rational analysis is used, the minimum speed margin must be enough to provide for atmospheric variations (such as horizontal gusts), and the penetration of jet streams or cold fronts), instrument errors, airframe production variations, and must not be less than Mach 0.05. (c) Design maneuvering speed V (1) V (i) V (ii) n is the limit maneuvering load factor used in design (2) The value of V (d) Design speed for maximum gust intensity, V (1) VB may not be less than the speed determined by the intersection of the line representing the maximum positive lift, CNMAX, and the line representing the rough air gust velocity on the gust V-n diagram, or VS1√ ng, whichever is less, where: (i) ng the positive airplane gust load factor due to gust, at speed V (ii) VS1 is the stalling speed with the flaps retracted at the particular weight under consideration. (2) VB need not be greater than VC. [Doc. No. 4080, 29 FR 17955, Dec. 18, 1964, as amended by Amdt. 23–7, 34 FR 13088, Aug. 13, 1969; Amdt. 23–16, 40 FR 2577, Jan. 14, 1975; Amdt. 23–34, 52 FR 1829, Jan. 15, 1987; Amdt. 23–24, 52 FR 34745, Sept. 14, 1987; Amdt. 23–48, 61 FR 5143, Feb. 9, 1996]
Title 14: Aeronautics and Space
PART 23—AIRWORTHINESS STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES
Subpart C—Structure
Flight Loads
§ 23.335 Design airspeeds.