Definition
Ethyl alcohol (ethanol) is the type of alcohol found in beer, wine, and spirits. It is a central nervous system depressant that impairs judgment, coordination, reaction time, vision, and balance, and is the only alcohol intended for human consumption. In aviation it is regulated under 14 CFR 91.17, which prohibits acting as a crewmember within 8 hours of consuming any alcoholic beverage, while under the influence, or with a blood alcohol concentration of 0.04% or greater.
Plain English
It's the alcohol in alcoholic drinks. Even small amounts slow the brain down and make flying unsafe, so the rules set firm time and blood-level limits before a pilot can fly.
Context Anchor
Seen in FAA discussions of alcohol use, fitness to fly, and how drinking affects pilot performance.
Derivation
Ethyl' comes from the chemical group ethyl (C2H5), and 'alcohol' traces back through Medieval Latin from Arabic al-kuhl, originally a fine powder and later any distilled essence. Knowing this helps a pilot see that 'alcohol' covers a family of substances; ethyl alcohol is the specific one in drinks, distinct from methyl or isopropyl alcohol used in fuels and cleaners.
Why Pilots Care
FAA regulations prohibit flying after consuming ethyl alcohol because even small amounts impair judgment, slow reaction time, and reduce the ability to maintain control of an aircraft.
Intuition Check
Do not assume ethyl alcohol only means hard liquor. Beer, wine, and liquor all contain ethyl alcohol, and all can impair a pilot.
Example Sentence 1
Because ethyl alcohol stays in the system for hours, the pilot finished her single beer well before the 8-hour cutoff to her morning flight.
Example Sentence 2
Even a single serving of ethyl alcohol the night before can leave measurable effects during the next day's flight.