14 CFR 91.121 - Altimeter settings.

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There are 10 Updates appearing in the Federal Register for 14 CFR 91. View below or at eCFR (GPOAccess)
§ 91.121 Altimeter settings.
(a) Each person operating an aircraft shall maintain the cruising altitude or flight level of that aircraft, as the case may be, by reference to an altimeter that is set, when operating—
(1) Below 18,000 feet MSL, to—
(i) The current reported altimeter setting of a station along the route and within 100 nautical miles of the aircraft;
(ii) If there is no station within the area prescribed in paragraph (a)(1)(i) of this section, the current reported altimeter setting of an appropriate available station; or
(iii) In the case of an aircraft not equipped with a radio, the elevation of the departure airport or an appropriate altimeter setting available before departure; or
(2) At or above 18,000 feet MSL, to 29.92″ Hg.
(b) The lowest usable flight level is determined by the atmospheric pressure in the area of operation as shown in the following table:
Current altimeter setting Lowest usable flight level
29.92 (or higher) 180
29.91 through 29.42 185
29.41 through 28.92 190
28.91 through 28.42 195
28.41 through 27.92 200
27.91 through 27.42 205
27.41 through 26.92 210
(c) To convert minimum altitude prescribed under §§ 91.119 and 91.177 to the minimum flight level, the pilot shall take the flight level equivalent of the minimum altitude in feet and add the appropriate number of feet specified below, according to the current reported altimeter setting:
Current altimeter setting Adjustment factor
29.92 (or higher) None
29.91 through 29.42 500
29.41 through 28.92 1,000
28.91 through 28.42 1,500
28.41 through 27.92 2,000
27.91 through 27.42 2,500
27.41 through 26.92 3,000

Title 14 published on 2014-01-01

The following are only the Rules published in the Federal Register after the published date of Title 14.

For a complete list of all Rules, Proposed Rules, and Notices view the Rulemaking tab.

  • 2014-07-25; vol. 79 # 143 - Friday, July 25, 2014
    1. 79 FR 43240 - Interpretation of the Special Rule for Model Aircraft
      GPO FDSys XML | Text
      DEPARTMENT OF TRANSPORTATION, Federal Aviation Administration
      Notice of interpretation with request for comment; Extension of comment period.
      The comment period for the notice of interpretation published June 25, 2014 (79 FR 36172), is extended. Comments must be received on or before September 23, 2014.
      14 CFR Part 91

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United States Code
U.S. Code: Title 42 - THE PUBLIC HEALTH AND WELFARE
USC: Title 49a
U.S. Code: Title 49 - TRANSPORTATION
Statutes at Large
Presidential Documents

Executive Order ... 11514

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 91 after this date.

  • 2014-07-25; vol. 79 # 143 - Friday, July 25, 2014
    1. 79 FR 43240 - Interpretation of the Special Rule for Model Aircraft
      GPO FDSys XML | Text
      DEPARTMENT OF TRANSPORTATION, Federal Aviation Administration
      Notice of interpretation with request for comment; Extension of comment period.
      The comment period for the notice of interpretation published June 25, 2014 (79 FR 36172), is extended. Comments must be received on or before September 23, 2014.
      14 CFR Part 91