There are three classes of FAA medical certificates and they all have different medical standards. The FAA medical standards are listed in Part 67 of the Federal Aviation Regulations. Each pilot, except those who fly gliders or free air balloons, must possess a valid FAA Medical Certificate in order to obtain or exercise the privileges of their pilot certificates and/or ratings. Read more here: http://www.helicopterschoollist.com/faa_helicopter_medical_certificates.php