14 CFR 23.345 - High lift devices.

§ 23.345 High lift devices.

(a) If flaps or similar high lift devices are to be used for takeoff, approach or landing, the airplane, with the flaps fully extended at VF, is assumed to be subjected to symmetrical maneuvers and gusts within the range determined by -

(1) Maneuvering, to a positive limit load factor of 2.0; and

(2) Positive and negative gust of 25 feet per second acting normal to the flight path in level flight.

(b) VF must be assumed to be not less than 1.4 VS or 1.8 VSF, whichever is greater, where -

(1) VS is the computed stalling speed with flaps retracted at the design weight; and

(2) VSF is the computed stalling speed with flaps fully extended at the design weight.

(3) If an automatic flap load limiting device is used, the airplane may be designed for the critical combinations of airspeed and flap position allowed by that device.

(c) In determining external loads on the airplane as a whole, thrust, slipstream, and pitching acceleration may be assumed to be zero.

(d) The flaps, their operating mechanism, and their supporting structures, must be designed to withstand the conditions prescribed in paragraph (a) of this section. In addition, with the flaps fully extended at VF, the following conditions, taken separately, must be accounted for:

(1) A head-on gust having a velocity of 25 feet per second (EAS), combined with propeller slipstream corresponding to 75 percent of maximum continuous power; and

(2) The effects of propeller slipstream corresponding to maximum takeoff power.

[Doc. No. 27805, 61 FR 5144, Feb. 9, 1996]

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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