Private Pilot Private Exam

What is the definition of night time in aviation terms?

1. The time from sunset to sunrise

2. The time between the end of evening civil twilight and the beginning of morning civil twilight

3. The entire period of darkness after sunset

4. The time when pilots must use instruments

The correct answer is: The time between the end of evening civil twilight and the beginning of morning civil twilight

The definition of night time in aviation terms is specifically defined as the period between the end of evening civil twilight and the beginning of morning civil twilight. This distinction is important for several reasons related to flight operations and regulatory requirements. Civil twilight is defined by the angle of the sun below the horizon, specifically when the sun is at 6 degrees below the horizon. During this time, there is still enough natural light for most outdoor activities, and visual flight rules can still apply. However, once civil twilight ends, pilots must acknowledge that they are operating in conditions that may require different operational procedures and requirements, such as using airplane lights and adhering to instrument flight rules under specific circumstances. This definition ensures that pilots understand their responsibilities and the limitations they may face when flying at night. Knowing the exact timing of this period helps in planning and ensuring safety, as it delineates the transition from daylight operations to nighttime operations, which may have different regulations regarding instrument use and visibility considerations.