FAA 107 Commercial Drone Pilot Practice Exam

During which time period is evening civil twilight defined?

1. 30 minutes before sunset

2. 30 minutes after sunset

3. One hour after sunset

4. One hour before sunrise

The correct answer is: 30 minutes after sunset

Evening civil twilight is defined as the duration that occurs 30 minutes after sunset. This period is significant because it marks the time when the sun is just below the horizon and sufficient natural light remains for most outdoor activities. During civil twilight, the horizon is still visible, and lights can be seen; it's an important consideration for drone pilots who may need to operate their aircraft safely while ensuring compliance with regulations regarding visibility and operational hours. Civil twilight is often broken down into three phases: civil, nautical, and astronomical twilight, which delineate the decreasing light conditions. In the context of drone operation, understanding these definitions is crucial as they influence the conditions under which a drone can be flown legally and safely. The other options refer to different times, either before sunset, such as 30 minutes or one hour before sunrise, which do not align with the established definition of evening civil twilight. Thus, they would not be applicable in the same context of evening visibility and operational conditions for aviation.