14 CFR · Part 35
14 CFR § 35.40
Functional test.
The variable-pitch propeller system must be subjected to the applicable functional tests of this section. The same propeller system used in the endurance test (§ 35.39) must be used in the functional tests and must be driven by a representative engine on a test stand or on an airplane. The propeller must complete these tests without evidence of failure or malfunction. This test may be combined with the endurance test for accumulation of cycles.
Manually-controllable propellers. Five hundred representative flight cycles must be made across the range of pitch and rotational speed.
Governing propellers. Fifteen hundred complete cycles must be made across the range of pitch and rotational speed.
Feathering propellers. Fifty cycles of feather and unfeather operation must be made.
Reversible-pitch propellers. Two hundred complete cycles of control must be made from lowest normal pitch to maximum reverse pitch. During each cycle, the propeller must run for 30 seconds at the maximum power and rotational speed selected by the applicant for maximum reverse pitch.
An analysis based on tests of propellers of similar design may be used in place of the tests of this section.
Regulations Referenced
Reflects the eCFR edition current as of September 29, 2026. Retrieved from ecfr.gov on October 16, 2026.
Primary Source