14 CFR 27.939 - Turbine engine operating characteristics.

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§ 27.939 Turbine engine operating characteristics.
(a) Turbine engine operating characteristics must be investigated in flight to determine that no adverse characteristics (such as stall, surge, or flameout) are present, to a hazardous degree, during normal and emergency operation within the range of operating limitations of the rotorcraft and of the engine.
(b) The turbine engine air inlet system may not, as a result of airflow distortion during normal operation, cause vibration harmful to the engine.
(c) For governor-controlled engines, it must be shown that there exists no hazardous torsional instability of the drive system associated with critical combinations of power, rotational speed, and control displacement.
[Amdt. 27-1, 32 FR 6914, May 5, 1967, as amended by Amdt. 27-11, 41 FR 55469, 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.

  • 2014-08-19; vol. 79 # 160 - Tuesday, August 19, 2014
    1. 79 FR 48946 - Special Conditions: Robinson Model R66 Helicopter, § 27.1309, Installation of HeliSAS Autopilot and Stabilization Augmentation System (AP/SAS)
      GPO FDSys XML | Text
      DEPARTMENT OF TRANSPORTATION, Federal Aviation Administration
      Final special conditions; request for comments.
      The effective date of these special conditions is August 7, 2014. We must receive your comments on or before October 3, 2014.
      14 CFR Part 27

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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 27 after this date.

  • 2014-08-19; vol. 79 # 160 - Tuesday, August 19, 2014
    1. 79 FR 48946 - Special Conditions: Robinson Model R66 Helicopter, § 27.1309, Installation of HeliSAS Autopilot and Stabilization Augmentation System (AP/SAS)
      GPO FDSys XML | Text
      DEPARTMENT OF TRANSPORTATION, Federal Aviation Administration
      Final special conditions; request for comments.
      The effective date of these special conditions is August 7, 2014. We must receive your comments on or before October 3, 2014.
      14 CFR Part 27