Is it permitted for Mr. Frank to apply his engineer's seal to reports and plans completed by his sons?

The guiding principle regarding the application of an engineer's seal emphasizes that an engineer can only apply their seal to work that they have personally prepared or directly supervised. The purpose of the seal is to indicate that the work meets professional standards and has been completed under the engineer's direction, ensuring accountability and adherence to ethical practices.

In this scenario, Mr. Frank applying his seal to reports and plans completed by his sons does not align with these principles, as the work was not prepared or supervised by him directly. This lack of direct involvement means he cannot vouch for the quality and integrity of the work, which is a fundamental expectation associated with the use of his engineer's seal. Therefore, the correct understanding is that it is not permitted for him to apply his seal under these circumstances.