14 CFR 23.333 - Flight envelope.

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§ 23.333 Flight envelope.

(a) General. Compliance with the strength requirements of this subpart must be shown at any combination of airspeed and load factor on and within the boundaries of a flight envelope (similar to the one in paragraph (d) of this section) that represents the envelope of the flight loading conditions specified by the maneuvering and gust criteria of paragraphs (b) and (c) of this section respectively.

(b) Maneuvering envelope. Except where limited by maximum (static) lift coefficients, the airplane is assumed to be subjected to symmetrical maneuvers resulting in the following limit load factors:

(1) The positive maneuvering load factor specified in § 23.337 at speeds up to V D;

(2) The negative maneuvering load factor specified in § 23.337 at V C; and

(3) Factors varying linearly with speed from the specified value at V C to 0.0 at V D for the normal and commuter category, and −1.0 at V D for the acrobatic and utility categories.

(c) Gust envelope.

(1) The airplane is assumed to be subjected to symmetrical vertical gusts in level flight. The resulting limit load factors must correspond to the conditions determined as follows:

(i) Positive (up) and negative (down) gusts of 50 f.p.s. at V C must be considered at altitudes between sea level and 20,000 feet. The gust velocity may be reduced linearly from 50 f.p.s. at 20,000 feet to 25 f.p.s. at 50,000 feet.

(ii) Positive and negative gusts of 25 f.p.s. at V D must be considered at altitudes between sea level and 20,000 feet. The gust velocity may be reduced linearly from 25 f.p.s. at 20,000 feet to 12.5 f.p.s. at 50,000 feet.

(iii) In addition, for commuter category airplanes, positive (up) and negative (down) rough air gusts of 66 f.p.s. at V β must be considered at altitudes between sea level and 20,000 feet. The gust velocity may be reduced linearly from 66 f.p.s. at 20,000 feet to 38 f.p.s. at 50,000 feet.

(2) The following assumptions must be made:

(i) The shape of the gust is -

Where -
s = Distance penetrated into gust (ft.);
C = Mean geometric chord of wing (ft.); and
Ude = Derived gust velocity referred to in subparagraph (1) of this section.

(ii) Gust load factors vary linearly with speed between V C and V D .

(d) Flight envelope.

[Doc. No. 4080, 29 FR 17955, Dec. 18, 1964, as amended by Amdt. 23-7, 34 FR 13087, Aug. 13, 1969; Amdt. 23-34, 52 FR 1829, Jan. 15, 1987]

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United States Code

Title 14 published on 2015-01-01

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

  • 2015-12-09; vol. 80 # 236 - Wednesday, December 9, 2015
    1. 80 FR 76379 - Special Conditions: Cirrus Aircraft Corporation, SF50; Auto Throttle
      GPO FDSys XML | Text
      DEPARTMENT OF TRANSPORTATION, Federal Aviation Administration
      Final special conditions.
      The effective date of these special conditions is December 9, 2015 and are applicable on December 2, 2015.
      14 CFR Part 23