Federal Aviation Regulations
14 CFR § 91.17 — Alcohol or drugs
Volume 2 · Title 14 of the Code of Federal Regulations, 2025 annual edition. U.S. Government work — public domain (17 U.S.C. §105).
The regulation, in full
Sec. 91.17 Alcohol or drugs.
(a) No person may act or attempt to act as a crewmember of a civil
aircraft--
(1) Within 8 hours after the consumption of any alcoholic beverage;
(2) While under the influence of alcohol;
(3) While using any drug that affects the person's faculties in any
way contrary to safety; or
(4) While having an alcohol concentration of 0.04 or greater in a
blood or breath specimen. Alcohol concentration means grams of alcohol
per deciliter of blood or grams of alcohol per 210 liters of breath.
(b) Except in an emergency, no pilot of a civil aircraft may allow a
person who appears to be intoxicated or who demonstrates by manner or
physical indications that the individual is under the influence of drugs
(except a medical patient under proper care) to be carried in that
aircraft.
(c) A crewmember shall do the following:
(1) On request of a law enforcement officer, submit to a test to
indicate the alcohol concentration in the blood or breath, when--
(i) The law enforcement officer is authorized under State or local
law to conduct the test or to have the test conducted; and
(ii) The law enforcement officer is requesting submission to the
test to investigate a suspected violation of State or local law
governing the same or substantially similar conduct prohibited by
paragraph (a)(1), (a)(2), or (a)(4) of this section.
(2) Whenever the FAA has a reasonable basis to believe that a person
may have violated paragraph (a)(1), (a)(2), or (a)(4) of this section,
on request of the FAA, that person must furnish to the FAA the results,
or authorize any clinic, hospital, or doctor, or other person to release
to the FAA, the results of each test taken within 4 hours after acting
or attempting to act as a crewmember that indicates an alcohol
concentration in the blood or breath specimen.
(d) Whenever the Administrator has a reasonable basis to believe
that a person may have violated paragraph (a)(3) of this section, that
person shall, upon
request by the Administrator, furnish the Administrator, or authorize
any clinic, hospital, doctor, or other person to release to the
Administrator, the results of each test taken within 4 hours after
acting or attempting to act as a crewmember that indicates the presence
of any drugs in the body.
(e) Any test information obtained by the Administrator under
paragraph (c) or (d) of this section may be evaluated in determining a
person's qualifications for any airman certificate or possible
violations of this chapter and may be used as evidence in any legal
proceeding under section 602, 609, or 901 of the Federal Aviation Act of
1958.
[Docket 18334, 54 FR 34292, Aug. 18, 1989, as amended by Amdt. 91-291,
June 21, 2006]What this means for the knowledge test
Our own study notes for this section — reviewed through our AI instructional-review system, not by a certificated flight instructor. Not an authoritative source.
A person may not act or attempt to act as a crewmember of a civil aircraft within 8 hours after consuming alcohol ("8 hours bottle to throttle"), while under the influence of alcohol, while using any drug that affects safety, or with a blood alcohol concentration of 0.04 percent or greater. These are minimums; the effects of alcohol and many drugs can impair a pilot well beyond the stated time limit, so a conservative pilot allows a wider margin.
14 CFR 91.17
A pilot may not act as a crewmember within 8 hours of consuming alcohol ("8 hours bottle to throttle"), while under the influence of alcohol, with a blood alcohol concentration of 0.04 percent or greater, or while using any drug that affects safety. Alcohol also causes histotoxic hypoxia by impairing the cells’ ability to use oxygen, and its effects are amplified at altitude.
14 CFR 91.17
Lessons that cover § 91.17
- Operating Rules: Right of Way, Alcohol and PIC Authority
- Personal Fitness to Fly: Alcohol, Drugs, Fatigue and IMSAFE
Practice questions on § 91.17 (2)
What is the minimum time that must elapse between consuming alcohol and acting as a crewmember?
Answer 8 hours
A person may not act as a crewmember within 8 hours of consuming alcohol, while under the influence, or with a blood alcohol concentration of 0.04 percent or greater.
Under the regulations, a pilot may not act as a crewmember within how long after consuming alcohol?
Answer 8 hours
A pilot may not act as a crewmember within 8 hours of consuming alcohol, while under the influence, or with a blood alcohol concentration of 0.04 percent or greater.