Final answer:
The two ratings for a mechanic certificate are Airframe and Powerplant, known as A&P ratings, and are crucial for mechanics in aviation.
Step-by-step explanation:
The two ratings that can be issued to a mechanic certificate are Airframe and Powerplant. These are commonly known as A&P ratings and are essential for aircraft mechanics within the United States. The Airframe rating allows mechanics to work on the aircraft structure, while the Powerplant rating permits them to work on engines. To become a certified mechanic with either or both of these ratings, individuals must attend an FAA-approved school or gain equivalent work experience, pass written examinations, and complete practical and oral tests.