Medical certifications are divided into three classes:

Third class

Third class certifications require the least involved examinations of all medical certifications. They are required for those intending to be pilot-in-command of an aircraft under the Private or Recreational pilot certificates or while exercising solo privileges while a student pilot.

To qualify for a third class medical certificate, pilots must meet the following requirements:

• Distant vision: 20/40 or better in each eye separately, with or without correction
• Near vision: 20/40 or better in each eye separately, with or without correction, as measured at a distance of 16 inches
• Color vision: Demonstrate the ability to perceive the colors necessary for the safe performance of airman duties
• Hearing: Demonstrate the ability to hear an average conversational voice in a quiet room, using both ears, at a distance of six feet, with their back turned to the examiner, or pass an approved audiometric test
• Ear, Nose, and Throat: Exhibit no ear disease or condition manifested by, or that may reasonably be expected to be manifested by, vertigo or a disturbance of speech or equilibrium
• Blood Pressure: Under 155/95
• Mental Status: No diagnosis of psychosis, bipolar disorder, or severe personality disorders
• Substance Dependence: No dependence on alcohol or any pharmacological substance in the previous two years

For pilots under 40 years of age, third class medical certificates expire on the last day of the month they were issued, three years from the date of issue. For all others, they expire on the last day of the month they were issued, two years from the date of issue.

Second class

Second class certifications are required for those intending to exercise the privileges of the commercial pilot certificate.

To qualify for a second class medical certificate, pilots must meet the requirements for the third class certificate plus:

• Distant vision: 20/20 or better in each eye separately, with or without correction
• Intermediate vision: 20/40 or better in each eye separately, with or without correction, at age 50 and over, as measured at 32 inches

Second class certificates are valid until the last day of the month, twelve months after they were issued. The certificate holder may then only exercise the privileges of a third class medical certificate.

First class

First class certificates are required for those intending to be pilot-in-command in an air carrier operation requiring an Airline Transport Pilot (ATP) certificate. Other operations, including those under Part 91, may require a first class medical for insurance purposes, although it is not a federal requirement in such cases.

To qualify for the first class medical certificate, pilots must meet the requirements for the third and second class certificates plus:

• Heart Function: Electrocardiogram must show normal heart function once at age 35 and annually for those age 40 and over

First class certificates are valid until the last day of the month, six months after they were issued. The certificate holder may then only exercise the privileges of a second class medical certificate.

Special issuance

Pilots who do not meet the above requirements may be issued a medical certificate under a "special issuance." A special issuance is essentially a waiver for a disqualifying condition and is evaluated on a case-by-case basis depending on the class of certificate requested. Minor problems can be overcome by a special issuance from an Aviation Medical Examiner, while others require a special issuance from the FAA directly.

Restrictions

Restrictions may be placed upon a medical certificate to mitigate any concern for safety. For instance, color-blind pilots are typically issued a restriction reading, "NOT VALID FOR NIGHT FLIGHT OR BY COLOR SIGNAL CONTROL." This mitigates the concern that color-blind pilots may not be able to identify those colors required for the performance of safe airman duties by preventing situations that are considered potentially unsafe.

In many cases, these restrictions can be removed through a "Statement of Demonstrated Ability" (SODA), or a "Letter of Evidence" from the FAA indicating that the pilot's deficiency is of no concern.