what is a first class medical certificate?

Answer 1

A first-class airman medical certificate is required to exercise the privileges of an airline transport pilot certificate. A first-class airman medical certificate is valid for 6 months plus the remainder of the days in the month of examination.
A second-class airman medical certificate is required for commercial, non-airline duties (e.g., for crop dusters, corporate pilots) and is valid for 1 year plus the remainder of the days in the month of examination. Those exercising the privileges of a flight engineer certificate, a flight navigator certificate, or acting as air traffic control tower operator must hold a second-class airman medical certificate.
A third-class airman medical certificate is required to exercise the privileges of a private pilot certificate, recreational pilot certificate, a flight instructor certificate, or a student pilot certificate. A third-class airman medical certificate is valid for 3 years plus the remainder of the days in the month of examination for pilots under age 40 or for 2 years plus the remainder of the days in the month of examination for those pilots age 40 and over.

This link will take you to an article about medical certificates

http://flighttraining.aopa.org/members/student_pilot/presolo/articles/medcert.cfm

Answer 2

There are 3 classes of medicals.
Class 3 is for private pilots
Class 2 is for Commercial Pilots
Class 1 is for AirLine Transport Pilots

This a is a basic breakdown, that is not to say a ATP can't fly privately (Far 91) with a class 3. But to exercise the privileges if a ATP he needs a Class 1.
Also the valid times are different. ie. class 1 is every 6 months, but can be used for a year if used with Commercial privileges, etc

Answer 3

A first class medical certificate is for anyone who wishes to be a pilot. It is mostly used for ATP certified pilots. If you just want to be a commercial pilot or a private pilot, then you don't need a first class medical certificate. A commercial pilot only needs a second class medical and a private pilot only needs a third class medical certificate. Please check the www.faa.gov website for additional information.