Duty refers to what?

• A. Hours of rest
• B. Time a crewmember is assigned to work
• C. Total flight time
• D. Time on reserve

Answer: (B)

Duty time is the period a crewmember is required to be on duty by the employer, including the time they are actually working and the time they are available to work (preparing, waiting for assignment, or on reserve if called). That’s why the best answer is the idea of being assigned to work—it's the window during which the crew member is expected to perform duties or be ready to perform them. Hours of rest are separate break periods, not duty. Total flight time only counts the time spent in the air, not the entire duty window. Time on reserve can fall under duty when the crewmember is required to be available, but the core concept is being assigned to work during that period.