its not a hernia he had repaired though
I looked at the procedure online against my better judgement and it appears to be attached to a few parts of the body. Seems to be in there pretty solid.
Is this the right list for the OP?
https://www.faa.gov/about/office_org/headquarters_offices/avs/offices/aam/ame/guide/media/AeromedicalNeuropsychologistList.pdf
they probably ran it every day. When you have ethanol in the fuel, when moisture and water gets into the tanks, the ethanol grabs the water and then phase separates from the gasoline.