Rules
Part 107 drug and alcohol rules: 8 hours, 0.04 and refusing a test
Section 107.27 applies 14 CFR 91.17 and 91.19 to anyone who manipulates the controls or acts as remote pilot in command or visual observer. That means no flying within 8 hours after drinking, none while impaired, none at 0.04 blood alcohol or higher, and none while using a drug that affects your faculties.
Who does 107.27 apply to?
Section 107.27 is short. A person who manipulates the flight controls of a small unmanned aircraft system, or who acts as a remote pilot in command or visual observer, must comply with 14 CFR 91.17 and 91.19. So the rule reaches the pilot at the sticks, the remote pilot in command if that is a different person, and the visual observer who never touches a control. A person who is not part of the flight crew, such as a client watching from the side, is not covered by this rule.
Sources (checked 2026-11-14): 14 CFR 107.27 (eCFR); 14 CFR 91.17 (eCFR); 14 CFR 91.19 (eCFR).
What does 91.17 prohibit?
The section states that a person may not act or attempt to act as a crewmember of a civil aircraft in four situations. Part 107 borrows these by reference.
| Paragraph | What is prohibited |
|---|---|
| (a)(1) | Within 8 hours after the consumption of any alcoholic beverage |
| (a)(2) | While under the influence of alcohol |
| (a)(3) | While using any drug that affects the person's faculties in any way contrary to safety |
| (a)(4) | While having an alcohol concentration of 0.04 or greater in a blood or breath specimen (grams of alcohol per deciliter of blood or per 210 liters of breath) |
These are separate conditions, and any one is a violation. In particular, the 8-hour rule does not depend on how you feel or what a breath test shows: a pilot who drank a beer 6 hours earlier and has a blood alcohol of 0.00 has still broken (a)(1). And a pilot who finished a drink 12 hours ago but is still impaired, or whose alcohol concentration is 0.04 or more, breaks (a)(2) or (a)(4) even though the 8 hours passed.
Sources (checked 2026-11-14): 14 CFR 91.17 (eCFR).
How does the rule treat medications?
Paragraph (a)(3) is about any drug that affects faculties in any way contrary to safety. It does not list only illegal drugs. A prescription pain killer, an over-the-counter sleep aid or an antihistamine that makes you drowsy can fall inside it if it affects your ability to operate safely. Separately, 107.17 bars flying if you know, or have reason to know, of a physical or mental condition that would interfere with the safe operation of the system. This also covers the visual observer and any other direct participant. The two rules overlap, so a medication that impairs you is a problem under both.
Sources (checked 2026-11-14): 14 CFR 107.17 (eCFR); 14 CFR 91.17 (eCFR).
What does 91.19 add?
Section 91.19 prohibits operating a civil aircraft in the United States while knowing that narcotic drugs, marihuana, or depressant or stimulant drugs, as defined in federal or state statutes, are on board. There is an exception when the carriage is authorized by a federal or state statute or agency. Under 107.27 this reaches the remote pilot in command, the person at the controls and the visual observer. The practical reading is that carrying a covered drug in a payload or in the aircraft is itself a problem, which also ties into the hazard rules in moving vehicles, hazmat and dropping objects.
Sources (checked 2026-11-14): 14 CFR 91.19 (eCFR).
What if law enforcement or the FAA asks for a test?
Paragraph (c) of 91.17 says a crewmember must, on the request of a law enforcement officer, submit to a test to indicate blood or breath alcohol concentration. The officer must be authorized under state or local law and must be investigating a suspected violation of a similar law covering the conduct in (a)(1), (a)(2) or (a)(4). If the FAA has a reasonable basis to believe a violation of those same paragraphs occurred, the person must provide on request the results of any test taken within 4 hours after acting or attempting to act, or authorize a clinic, hospital, doctor or other person to release them.
Paragraph (d) covers drugs: if the FAA has a reasonable basis to believe a violation of (a)(3) occurred, the person must, on request, provide the results of a test taken within 4 hours that show any drugs present, or authorize their release.
Sources (checked 2026-11-14): 14 CFR 91.17 (eCFR).
What are the consequences under 107.57 and 107.59?
The regulations tie violations to the remote pilot certificate.
| Section | Trigger | Consequence in the rule text |
|---|---|---|
| 107.57(a) | A conviction under any federal or state law relating to growing, processing, manufacturing, selling, disposing of, possessing, transporting or importing narcotic drugs, marijuana, or depressant or stimulant drugs or substances | Grounds for denying an application for a remote pilot certificate with a small UAS rating for up to 1 year after the final conviction, or for suspending or revoking an existing rating |
| 107.57(b) | Committing an act prohibited by 91.17(a) or 91.19(a) | Grounds for denying an application for up to 1 year after the act, or for suspending or revoking an existing rating |
| 107.59 | Refusing a blood alcohol test requested by law enforcement under 91.17(c), or refusing to provide or authorize release of test results requested by the FAA under 91.17(c) or (d) | Grounds for denying an application for up to 1 year after the refusal, or for suspending or revoking an existing rating |
Note the wording: these are grounds for action. The sections say what the FAA may do, not what happens in every case. They also run both ways: a person who has no certificate yet can have an application denied.
Sources (checked 2026-11-14): 14 CFR 107.57 (eCFR); 14 CFR 107.59 (eCFR).
How do I work through test scenarios?
Worked example
Dinner and a morning flight
Say a pilot finishes a glass of wine at 9:00 p.m. and plans to fly at 4:00 a.m. next morning. That is 7 hours, which falls inside the 8-hour window of 91.17(a)(1), so the pilot cannot fly until 5:00 a.m. at the earliest, regardless of how clear-headed the pilot feels. The rule sets a minimum; being past 8 hours does not guarantee that the pilot is unimpaired.
Worked example
A visual observer with a cold medicine
Say the visual observer took a cold tablet that causes drowsiness at lunch, and the flight is at 3:00 p.m. The observer never touches the controls, but 107.27 covers visual observers. If the tablet affects the observer's faculties in a way contrary to safety, 91.17(a)(3) applies. The remote pilot in command should talk with the observer before launch and replace them if there is any doubt. Under 107.49(b) the briefing is the place to raise this.
Quick answers to common test setups:
- Number to remember for the hours: 8. For the concentration: 0.04.
- Observers are covered. So is the remote pilot in command who is not at the controls.
- Refusing a test requested by law enforcement is grounds for action under 107.59 even if you were not impaired.
- The 8 hours is from the last consumption, and it stands alone as a violation.
Sources (checked 2026-11-14): 14 CFR 91.17 (eCFR); 14 CFR 107.27 (eCFR); 14 CFR 107.49 (eCFR).
Where do physiology and fitness fit in?
The ACS knowledge area on physiological effects of drugs and alcohol sits next to these rules, and fatigue, stress and medication are treated as hazardous attitudes and risk factors in the decision-making material. Read aeronautical decision-making for the Part 107 test for the risk-assessment side, and Part 107 operating rules for the rest of the pilot-in-command duties.
How do I stay safe with these rules in real life?
The rules set a floor. Treat the 8-hour minimum as a floor and add your own margin when you have slept badly or had a heavy evening. Check labels on every medication you take for drowsiness or warnings about operating machinery, and ask a pharmacist when unsure. Make "I am not fit to fly today" a normal call that anyone on the crew can make without argument. Under 107.17, a crew member who knows of a condition that would interfere with safe operation must not fly, and that covers fatigue and illness as well as medication.
Worked example
The last-minute swap
Say your regular visual observer cancels and a friend offers to fill in. Before launch you ask the usual questions: has either of you had alcohol in the last 8 hours, taken any medication that causes drowsiness, or slept less than normal? If the friend admits to a beer at lunch four hours ago, 91.17(a)(1) rules out the flight crew role, and you find someone else or reschedule.
Note your preflight briefing in whatever logbook you keep, and include a line for this check. It helps if anyone later asks what you knew before the flight.
Sources (checked 2026-11-14): 14 CFR 107.17 (eCFR); 14 CFR 107.49 (eCFR); 14 CFR 91.17 (eCFR).
Related guides
- Part 107 operating rules: altitude, speed, visibility and clouds
- Aeronautical decision-making, CRM and human factors
- Part 107 visual line of sight and visual observers explained
- Part 107 moving vehicles, hazardous materials and dropping objects
- All Part 107 guides
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Sources
- 14 CFR 107.27 (eCFR), checked 2026-11-14
- 14 CFR 91.17 (eCFR), checked 2026-11-14
- 14 CFR 91.19 (eCFR), checked 2026-11-14
- 14 CFR 107.57 (eCFR), checked 2026-11-14
- 14 CFR 107.59 (eCFR), checked 2026-11-14
- 14 CFR 107.17 (eCFR), checked 2026-11-14
How this page was made: written by Certloom Learning from the sources above, with the rules checked against the current regulation text. Practice items are original questions from the app's reviewed bank. Spot an error? certloomlearning@gmail.com.