14 CFR §35.41

1. (a)When the applicant seeks approval of a transient maximum propeller overspeed, the applicant must demonstrate that the propeller is capable of further operation without maintenance action at the maximum propeller overspeed condition. This may be accomplished by:
   1. (1)Performance of 20 runs, each of 30 seconds duration, at the maximum propeller overspeed condition; or
   2. (2)Analysis based on test or service experience.
2. (b)When the applicant seeks approval of a transient maximum propeller overtorque, the applicant must demonstrate that the propeller is capable of further operation without maintenance action at the maximum propeller overtorque condition. This may be accomplished by:
   1. (1)Performance of 20 runs, each of 30 seconds duration, at the maximum propeller overtorque condition; or
   2. (2)Analysis based on test or service experience.