14 C.F.R. Subpart B—Design and Construction
Title 14 - Aeronautics and Space
This subpart prescribes the design and construction requirements for propellers. Each applicant must show that the propeller concerned meets the design and construction requirements of this subpart. The propeller may not have design features that experience has shown to be hazardous or unreliable. The suitability of each questionable design detail or part must be established by tests. The suitability and durability of materials used in the propeller must— (a) Be established on the basis of experience or tests; and (b) Conform to approved specifications (such as industry or military specifications, or Technical Standard Orders) that ensure their having the strength and other properties assumed in the design data. (Secs. 313(a), 601, and 603, 72 Stat. 752, 775, 49 U.S.C. 1354(a), 1421, and 1423; sec. 6(c), 49 U.S.C. 1655(c)) [Amdt. 35–4, 42 FR 15047, Mar. 17, 1977] Each part of the propeller must be designed and constructed to minimize the development of any unsafe condition of the propeller between overhaul periods. A reversible propeller must be adaptable for use with a reversing system in an airplane so that no single failure or malfunction in that system during normal or emergency operation will result in unwanted travel of the propeller blades to a position substantially below the normal flight low-pitch stop. Failure of structural elements need not be considered if the occurrence of such a failure is expected to be extremely remote. For the purposes of this section the term “reversing system” means that part of the complete reversing system that is in the propeller itself and those other parts that are supplied by the applicant for installation in the aircraft. (a) No loss of normal propeller pitch control may cause hazardous overspeeding of the propeller under intended operating conditions. (b) Each pitch control system that is within the propeller, or supplied with the propeller, and that uses engine oil for feathering, must incorporate means to override or bypass the normally operative hydraulic system components so as to allow feathering if those components fail or malfunction. (c) Each propeller approved for installation on a turbopropeller engine must incorporate a provision for an indicator to indicate when the propeller blade angle is below the flight low pitch position. The provision must directly sense the blade position and be arranged to cause an indicator to indicate that the blade angle is below the flight low pitch position before the blade moves more than 8° below the flight low pitch stop. [Amdt. 35–2, 32 FR 3737, Mar. 4, 1967, as amended by Amdt. 35–5, 45 FR 60182, Sept. 11, 1980]
Title 14: Aeronautics and Space
PART 35—AIRWORTHINESS STANDARDS: PROPELLERS
Subpart B—Design and Construction
§ 35.11 Applicability.
§ 35.13 General.
§ 35.15 Design features.
§ 35.17 Materials.
§ 35.19 Durability.
§ 35.21 Reversible propellers.
§ 35.23 Pitch control and indication.
