Final answer:
The required test plan design approval by a project engineer before implementation indicates a mandatory dependency or hard logic in project management.
Step-by-step explanation:
The question "The test plan design must be approved by the project engineer prior to implementation. This represents what type of dependency?" relates to the concept of project management within the field of engineering. In this case, the type of dependency being described is known as mandatory dependency, as it is a required action that needs to be completed before the project can proceed to the next phase. Mandatory dependencies are also known as hard logic, which is a logical relationship inherent in the work that cannot be changed or altered.