Which portion of the AD is applicable for a specific engine model after a given number of operating hours?

The section in the Airworthiness Directive (AD) that applies to a specific engine model after a certain number of operating hours outlines the inspection requirements or maintenance actions that must be taken once that engine reaches a specified threshold. This part of the AD is crucial because it provides essential information regarding the airworthiness and operational safety of the engine, ensuring that it remains reliable and performs satisfactorily after prolonged use.

Specifically, the chosen answer correlates with how ADs are structured, where certain sections, such as B, address specific criteria or actions that must be adhered to based on operational data like flight hours. These directives are implemented by the FAA to ensure that any potential issues that could arise due to fatigue or wear are monitored and addressed promptly.

Other options may refer to different sections that deal with other parameters or conditions, such as general maintenance practices or non-operational factors, thus emphasizing that B contains the relevant information regarding operational hours for a specific engine model.