I'm not sure how the student could be PIC. At the few flight schools with whom I've flown, the CFI is always PIC per insurance requirements. Unless the CFI is flying without compensation, how could he or she have only a third class medical?
Plus, even if somehow I missed a reg on that one, you can't get paid to ferry planes to maintenance, etc., without a second class, so you might as well keep it current.
Originally Posted by mcartier713
... and yes, you're only required to have a 3rd class medical to instruct. 119.1(e)(1) excludes it from being a "commercial operation"...
Part 119.1(e) has to do with exemption from requiring an air carrier certificate, I believe. Correct me if I'm wrong, but that doesn't have anything to do with whether CFIs need second class medicals while instructing.