Every pilot must obtain a medical certificate in order to exercise the privileges of their pilot’s license. There are three classes of medical certificates:
a) 1st class medical, valid for six months, and required for use with an Airline Transport rating;
b) 2nd class medical, valid for one year and required for use with a Commercial rating;
c) 3rd class medical, valid for three years if you are under 40, and for two years if 40 or older. Your medical certificate also acts as a student license while you are in training.