All mechanics are FRC employees. Not all employees are mechanics.
Some mechanics are specialized in engine (EN) maintenance. Some mechanics are specialized in airframe (AF) maintenance. Some mechanics are specialized in avionics (AV) maintenance. (Avionics are the electronic components of an aircraft that are used in communication and navigation.) All mechanics take periodic refresher courses to stay current in their areas of expertise. FRC tracks all course taken by each mechanic-date, course type, certification (Y/N), and performance.
FRC keeps a history of the employment of all mechanics. The history includes the date hired, date promoted, date terminated, and so on. (Note: The "and so on" component is, of course, not a real-world requirement. Instead, it has been used here to limit the number of attributes you will show in your design.)
Given those requirements, create the Crow's Foot ERD segment.