Definition
A chronic, progressive disease of the central nervous system in which the protective covering around nerve fibers (myelin) is damaged, disrupting communication between the brain and the rest of the body. Symptoms can include vision problems, muscle weakness, numbness, balance and coordination difficulties, fatigue, and cognitive changes. Multiple sclerosis is a medically disqualifying condition under FAA standards and requires a special issuance medical certificate to fly.
Plain English
A long-term illness that damages the nerves and can cause weakness, vision trouble, balance problems, and tiredness. The FAA does not allow pilots with this condition to fly on a standard medical certificate; they must apply for a special exception.
Context Anchor
Seen when reviewing medical conditions that may affect a pilot’s ability to qualify for or keep an FAA medical certificate.
Derivation
From Latin multiplex meaning many, and Greek skleros meaning hard. The name describes the multiple hardened scar patches (sclerosis) that form on nerve tissue throughout the body as the disease progresses.
Why Pilots Care
A diagnosis of multiple sclerosis must be reported on FAA medical applications; symptoms such as fatigue, vision changes, or muscle weakness can affect flight safety and typically require special-issuance review or result in denial.
Intuition Check
Do not assume multiple sclerosis is simply muscle stiffness or ordinary tiredness. It is a nervous-system disease that can affect several body functions, sometimes in changing or unpredictable ways.
Example Sentence 1
After being diagnosed with multiple sclerosis, the pilot grounded himself and began the FAA special issuance process.
Example Sentence 2
Because of multiple sclerosis symptoms, the pilot was advised to consult an aviation medical examiner before resuming flight duties.