14 CFR § 35.36
Bird impact
July 13, 2020
The applicant must demonstrate, by tests or analysis based on tests or experience on similar designs, that the propeller can withstand the impact of a 4-pound bird at the critical location(s) and critical flight condition(s) of a typical installation without causing a major or hazardous propeller effect. This section does not apply to fixed-pitch wood propellers of conventional design.
[Amdt. 35-8, 73 FR 63348, Oct. 24, 2008]