Fitness for Flight | Excerpts from AIM

1. Most pilots need valid medical certificates in order to exercise the privileges of their airman certificates. The exemption regulations are suprisingly complex about flight operations excused from formal medical certification, but in general all aviators except those flying gliders, light sport aircraft and free air balloons need current medical certificates (valid, unexpired flight physicals). The periodic medical examinations required for medical certification are conducted by designated Aviation Medical Examiners (AMEs) who have legal authority to issue medical certificates. AMEs are physicians with a special interest in aviation safety and training in aviation medicine. Depending on the pilot's age and the privileges s/he seeks to exercise, the medical certificate is valid from 6 - 60 months (details...).

2. The legal standards for medical certification are revealed in Title 14 of the Code of Federal Regulations, part 67. Pilots who have a history of certain medical conditions summarized on this these standards summary are disqualified from flying. Per the 2014 AME Guide, the list of disqualifying medical conditions includes a personality disorder manifested by overt acts, a psychosis, alcoholism, drug dependence, epilepsy, an unexplained disturbance of consciousness, myocardial infarction, angina pectoris and diabetes requiring medication for its control. Other medical conditions may be temporarily disqualifying, such as acute infections, anemia, and peptic ulcer. Pilots who do not meet medical standards may still be qualified under special issuance provisions. This may require that either additional medical information be provided or that a dedicated practical flight tests be conducted. These practical tests are called Medical Flight Tests.

3. Student pilots should visit an Aviation Medical Examiner as soon as possible in their flight training in order to avoid unnecessary training expenses should they not meet the medical standards. For the same reason, the student pilot who plans to enter commercial aviation should apply for the highest class of medical certificate that might be necessary in the pilot's career.