What defines "night time" for aviation purposes?

For aviation purposes, "night time" is defined as the period from the end of evening civil twilight to the beginning of morning civil twilight. This definition is important because it establishes the time frame during which specific regulations and requirements apply, especially concerning pilot certification and aircraft operations.

Civil twilight is the time when the sun is just below the horizon, creating enough light for most outdoor activities without artificial lighting. By defining night time based on civil twilight's beginning and end, the aviation regulations focus on the actual ambient light conditions, which are critical for flight operations. During this period, pilots are subject to additional requirements, such as the need for specific night flight training and logged flight hours to operate at night.

Ultimately, understanding this definition helps pilots comply with regulations regarding night flying and ensures they are fully equipped to handle the challenges presented by reduced visibility conditions typical of nighttime flying.