Which regulation provides guidance on determining the classification of powerplant repairs?

The regulation that provides guidance on determining the classification of powerplant repairs is 14 CFR Part 43. This part outlines the maintenance, preventive maintenance, rebuilding, and alteration of aircraft, including their components like powerplants. Specifically, it includes details about what constitutes major repairs versus minor repairs and the necessary documentation and protocols for each.

Understanding these distinctions is crucial for maintenance personnel to ensure compliance with FAA standards. Proper classification influences the type of maintenance recordkeeping required, the need for FAA Form 337 for major repairs, and the regulations surrounding the return of aircraft to service after repairs.

Other choices, such as 14 CFR Part 91 and 14 CFR Part 145, pertain to general operating rules and the requirements for repair stations, respectively, but they do not directly address the classification of repairs. Meanwhile, 14 CFR Part 91.417 focuses on maintenance records and does not provide the detail necessary for classifying repairs. Thus, 14 CFR Part 43 is the correct reference for understanding the classification of powerplant repairs.