Code of Federal Regulations

Title 14 - Aeronautics and Space
Volume: 1Date: 2023-01-01Original Date: 2023-01-01Title: Section 25.939 - Turbine engine operating characteristics.Context: Title 14 - Aeronautics and Space. CHAPTER I - FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION. SUBCHAPTER C - AIRCRAFT. PART 25 - AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES. Subpart E - Powerplant. - General.
ยงโ€‰25.939 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 airplane and of the engine. (b) [Reserved] (c) The turbine engine air inlet system may not, as a result of air flow distortion during normal operation, cause vibration harmful to the engine. [Amdt. 25โ€“11, 32 FR 6912, May 5, 1967, as amended by Amdt. 25โ€“40, 42 FR 15043, Mar. 17, 1977]