I have a prospective student with a history of kidney stones. He states that he has had 3 stones approximately 5 years in between each instance. It has been over 5 years since his last stone. Will he be able to get a 3rd class medical without an SI and if so what will be the effect on his medical if he has another stone? His past history makes it seem that he is probably due for another stone sooner than later. When I had my first medical I had a history of a single stone and it had been longer than 5 years since it happened, my AME issued my medical in the office. I don’t know if he can expect the same thing since his history includes more than one stone. If this is going to be a big issue for him then he would prefer to go Sport Pilot rather than spending a lot of money to meet the requirements of an SI, so I am trying to give him advice before he goes to the AME. I have already recommended that he schedule a consultation, but not physical, with the AME that issued my first medical.