14 CFR 23.425 - Gust loads.

§ 23.425 Gust loads.

(a) Each horizontal surface, other than a main wing, must be designed for loads resulting from -

(1) Gust velocities specified in § 23.333(c) with flaps retracted; and

(2) Positive and negative gusts of 25 f.p.s. nominal intensity at VF corresponding to the flight conditions specified in § 23.345(a)(2).

(b) [Reserved]

(c) When determining the total load on the horizontal surfaces for the conditions specified in paragraph (a) of this section, the initial balancing loads for steady unaccelerated flight at the pertinent design speeds VF, VC, and VD must first be determined. The incremental load resulting from the gusts must be added to the initial balancing load to obtain the total load.

(d) In the absence of a more rational analysis, the incremental load due to the gust must be computed as follows only on airplane configurations with aft-mounted, horizontal surfaces, unless its use elsewhere is shown to be conservative:

where -
ΔLht = Incremental horizontal tailload (lbs.);
Kg = Gust alleviation factor defined in § 23.341;
Ude = Derived gust velocity (f.p.s.);
V = Airplane equivalent speed (knots);
aht = Slope of aft horizontal lift curve (per radian)
Sht = Area of aft horizontal lift surface (ft 2); and
[Doc. No. 4080, 29 FR 17955, Dec. 18, 1964, as amended by Amdt. 23-7, 34 FR 13089 Aug. 13, 1969; Amdt. 23-42, 56 FR 353, Jan. 3, 1991]

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United States Code

Title 14 published on 2015-11-17

The following are ALL rules, proposed rules, and notices (chronologically) published in the Federal Register relating to 14 CFR Part 23 after this date.

  • 2017-02-08; vol. 82 # 25 - Wednesday, February 8, 2017
    1. 82 FR 9677 - Revisions to Operational Requirements for the Use of Enhanced Flight Vision Systems (EFVS) and to Pilot Compartment View Requirements for Vision Systems
      GPO FDSys XML | Text
      DEPARTMENT OF TRANSPORTATION, Federal Aviation Administration
      Final rule; delay of effective date.
      The effective date of the rule amending 14 CFR parts 1, 23, 25, 27, 29, 61, 91, 121, 125, and 135 published at 81 FR 90126, December 13, 2016, is delayed until March 21, 2017, except for the amendments to §§ 61.66 (amendatory instruction no. 15), 91.175 (amendatory instruction no. 18), 91.1039 (amendatory instruction no. 23), 121.651 (amendatory instruction no. 27), 125.325 (amendatory instruction no. 33), 125.381 (amendatory instruction no. 35), and 135.225 (amendatory instruction no. 38), which are effective March 13, 2018.
      14 CFR Parts 1, 23, 25, 27, 29, 61, 91, 121, 125, and 135
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