14 CFR 25.331 - Symmetric maneuvering conditions.

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§ 25.331 Symmetric maneuvering conditions.
(a) Procedure. For the analysis of the maneuvering flight conditions specified in paragraphs (b) and (c) of this section, the following provisions apply:
(1) Where sudden displacement of a control is specified, the assumed rate of control surface displacement may not be less than the rate that could be applied by the pilot through the control system.
(2) In determining elevator angles and chordwise load distribution in the maneuvering conditions of paragraphs (b) and (c) of this section, the effect of corresponding pitching velocities must be taken into account. The in-trim and out-of-trim flight conditions specified in § 25.255 must be considered.
(b) Maneuvering balanced conditions. Assuming the airplane to be in equilibrium with zero pitching acceleration, the maneuvering conditions A through I on the maneuvering envelope in § 25.333(b) must be investigated.
(c) Pitch maneuver conditions. The conditions specified in paragraphs (c)(1) and (2) of this section must be investigated. The movement of the pitch control surfaces may be adjusted to take into account limitations imposed by the maximum pilot effort specified by § 25.397(b), control system stops and any indirect effect imposed by limitations in the output side of the control system (for example, stalling torque or maximum rate obtainable by a power control system.)
(1) Maximum pitch control displacement at V A. The airplane is assumed to be flying in steady level flight (point A1, § 25.333(b)) and the cockpit pitch control is suddenly moved to obtain extreme nose up pitching acceleration. In defining the tail load, the response of the airplane must be taken into account. Airplane loads that occur subsequent to the time when normal acceleration at the c.g. exceeds the positive limit maneuvering load factor (at point A2 in § 25.333(b)), or the resulting tailplane normal load reaches its maximum, whichever occurs first, need not be considered.
(2) Specified control displacement. A checked maneuver, based on a rational pitching control motion vs. time profile, must be established in which the design limit load factor specified in § 25.337 will not be exceeded. Unless lesser values cannot be exceeded, the airplane response must result in pitching accelerations not less than the following:
(i) A positive pitching acceleration (nose up) is assumed to be reached concurrently with the airplane load factor of 1.0 (Points A1 to D1, § 25.333(b)). The positive acceleration must be equal to at least
where—
n is the positive load factor at the speed under consideration, and V is the airplane equivalent speed in knots.
(ii) A negative pitching acceleration (nose down) is assumed to be reached concurrently with the positive maneuvering load factor (points A2 to D2, § 25.333(b)). This negative pitching acceleration must be equal to at least
where—
n is the positive load factor at the speed under consideration; and V is the airplane equivalent speed in knots.
[Doc. No. 5066, 29 FR 18291, Dec. 24, 1964, as amended by Amdt. 25-23, 35 FR 5672, Apr. 8, 1970; Amdt. 25-46, 43 FR 50594, Oct. 30, 1978; 43 FR 52495, Nov. 13, 1978; 43 FR 54082, Nov. 20, 1978; Amdt. 25-72, 55 FR 29775, July 20, 1990; 55 FR 37607, Sept. 12, 1990; Amdt. 25-86, 61 FR 5220, Feb. 9, 1996; Amdt. 25-91, 62 FR 40704, July 29, 1997]

Title 14 published on 2014-01-01

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  • 2014-06-16; vol. 79 # 115 - Monday, June 16, 2014
    1. 79 FR 34215 - Special Conditions: Bombardier Aerospace, Models BD-500-1A10 and BD-500-1A11; Limit Engine Torque Loads
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      DEPARTMENT OF TRANSPORTATION, Federal Aviation Administration
      Final special conditions; request for comments.
      The effective date of these special conditions is June 16, 2014. We must receive your comments by July 31, 2014.
      14 CFR Part 25

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Title 14 published on 2014-01-01

The following are ALL rules, proposed rules, and notices (chronologically) published in the Federal Register relating to 14 CFR 25 after this date.

  • 2014-07-07; vol. 79 # 129 - Monday, July 7, 2014
    1. 79 FR 38266 - Harmonization of Airworthiness Standards—Fire Extinguishers and Class B and F Cargo Compartments
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      DEPARTMENT OF TRANSPORTATION, Federal Aviation Administration
      Notice of proposed rulemaking (NPRM).
      Send comments on or before October 6, 2014.
      14 CFR Part 25