Definition
A chronic medical condition in which the body cannot properly regulate blood sugar (glucose) levels, either because the pancreas does not produce enough insulin or because the body does not respond normally to the insulin it makes. Untreated or poorly controlled diabetes can cause episodes of very high or very low blood sugar, both of which can impair vision, judgment, and consciousness.
Plain English
A long-term condition where the body has trouble controlling the amount of sugar in the blood. Without proper management, blood sugar can swing too high or too low, which can affect how a person thinks, sees, and feels.
Context Anchor
Seen when a pilot applies for or renews an FAA medical certificate and must report medical conditions that could affect safe flying.
Derivation
From Greek 'diabetes' meaning 'to pass through' (referring to frequent urination, an early recognized symptom) and Latin 'mellitus' meaning 'honey-sweet' (because the urine of untreated patients contains sugar). The name itself describes the original way doctors recognized the condition.
Why Pilots Care
Uncontrolled diabetes can impair judgment, vision, and reaction time, so pilots must demonstrate stable management to obtain or retain an FAA medical certificate.
Intuition Check
Diabetes mellitus does not automatically mean a pilot can never receive a medical certificate. It means the FAA needs to know whether the pilot’s blood sugar is controlled well enough for safe flying.
Example Sentence 1
The applicant disclosed diabetes mellitus on the medical application and was directed to apply for a Special Issuance medical certificate.
Example Sentence 2
During the flight physical the examiner reviewed the applicant's diabetes mellitus treatment plan before issuing the certificate.