14 CFR 29.931 - Shafting critical speed.

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§ 29.931 Shafting critical speed.
(a) The critical speeds of any shafting must be determined by demonstration except that analytical methods may be used if reliable methods of analysis are available for the particular design.
(b) If any critical speed lies within, or close to, the operating ranges for idling, power-on, and autorotative conditions, the stresses occurring at that speed must be within safe limits. This must be shown by tests.
(c) If analytical methods are used and show that no critical speed lies within the permissible operating ranges, the margins between the calculated critical speeds and the limits of the allowable operating ranges must be adequate to allow for possible variations between the computed and actual values.
[Amdt. 29-12, 41 FR 55472, Dec. 20, 1976]

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.

  • 2014-12-31; vol. 79 # 250 - Wednesday, December 31, 2014
    1. 79 FR 78694 - Special Conditions: Airbus Helicopters Deutschland GmbH Model MBB-BK117D-2 Helicopters; Use of 30-Minute Power Rating
      GPO FDSys XML | Text
      DEPARTMENT OF TRANSPORTATION, Federal Aviation Administration
      Final special conditions; request for comments.
      This action is effective on Airbus Helicopters Deutschland GmbH Model MBB-BK117D-2 Helicopters on December 19, 2014. We must receive your comments by March 2, 2015.
      14 CFR Part 29

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United States Code

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 29 after this date.

  • 2014-12-31; vol. 79 # 250 - Wednesday, December 31, 2014
    1. 79 FR 78694 - Special Conditions: Airbus Helicopters Deutschland GmbH Model MBB-BK117D-2 Helicopters; Use of 30-Minute Power Rating
      GPO FDSys XML | Text
      DEPARTMENT OF TRANSPORTATION, Federal Aviation Administration
      Final special conditions; request for comments.
      This action is effective on Airbus Helicopters Deutschland GmbH Model MBB-BK117D-2 Helicopters on December 19, 2014. We must receive your comments by March 2, 2015.
      14 CFR Part 29