How long must you not consume alcohol prior to beginning a flight assignment?

• A. 12 hours
• B. 8 hours
• C. 24 hours
• D. 6 hours

Answer: (A)

Alcohol must be abstained from for twelve hours before starting a flight assignment. This time allows the body to metabolize any alcohol in your system and reduces the chance that impairment could affect judgment, coordination, or reaction time during flight. In Part 135 operations, this twelve-hour window is the standard required before you may perform crewmember duties. Shorter periods, like eight or six hours, do not provide the same safety margin, and twenty-four hours is more conservative than required for this scenario. If you haven’t met the twelve-hour abstinence, you should not fly.