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FAA Alcohol Rules: The 8-Hour Bottle-to-Throttle Rule Explained

Complete guide to FAA alcohol regulations under §91.17. Covers the 8-hour rule, 0.04% BAC limit, drug prohibitions, DUI reporting requirements, and certificate actions the FAA can take.

April 2026·6 min read read·Faraim Editorial

KEY POINT

The FAA's alcohol rules are stricter than most pilots realize. The 8-hour bottle-to-throttle rule is just the starting point. Here's the complete breakdown of §91.17 and what it means for your certificate.

The FAA's alcohol regulation, 14 CFR §91.17, is one of the clearest regulations in the entire FAR — and one of the most violated. Pilots often focus on the '8-hour rule' while forgetting the other provisions that are equally binding.

The Four Prohibitions Under §91.17

No person may act or attempt to act as a crewmember of a civil aircraft:

Within 8 hours after the consumption of any alcoholic beverage
While under the influence of alcohol
While having a blood alcohol concentration (BAC) of 0.04% or greater
While using any drug that affects the person's faculties in any way contrary to safety

The 8-Hour Rule in Practice

Eight hours is the minimum time you must wait after consuming any alcoholic beverage before acting as a crewmember. This doesn't care about quantity — one beer means 8 hours, just like a bottle of whiskey means 8 hours.

But here's the catch: 8 hours may not be enough. A large amount of alcohol the night before can still leave you with a BAC above 0.04% after 8 hours. The rule provides a minimum — your BAC must still be below 0.04% when you fly. That's why many pilots use the informal guideline of 12-24 hours when significant consumption occurred.

'Under the Influence' Is a Separate Standard

Even if your BAC is technically below 0.04%, you violate §91.17 if you fly 'under the influence of alcohol.' This is a subjective standard — any impairment of judgment, coordination, or cognitive function counts. The 8-hour rule and the 0.04% limit are objective standards. 'Under the influence' is an additional, catch-all prohibition.

Drugs and Medications

The fourth provision is broad: no drug that affects your faculties in any way contrary to safety. This includes prescription medications with drowsiness side effects, antihistamines, sedatives, and many common over-the-counter medications. The FAA's guidance is: if in doubt, don't fly. The AOPA's online medication lookup tool and the FAA's AME consultation service can help determine if a specific medication is acceptable.

DUI and the FAA

The FAA requires pilots to report any conviction for driving under the influence of alcohol or drugs within 60 days of the conviction under §61.15. Failure to report is a separate violation that can result in certificate suspension — often treated more seriously than the underlying DUI. Additionally, motor vehicle actions (MVAs) related to alcohol must be reported on medical certificate applications, and the FAA receives driver's license information from states under their motor vehicle record agreement.

The practical rule used by many professional pilots: 12 hours for social drinking, 24 hours after any significant consumption. The 8-hour rule is a legal minimum, not a safety standard.