Definition
For aviation purposes, the times of sunset and sunrise are the moments published in the American Air Almanac, converted to local time for the location concerned. These published times define when certain regulatory requirements take effect, including aircraft position lighting requirements and the boundaries of civil twilight in Alaska.
Plain English
In aviation rules, sunset and sunrise are not when you personally see the sun go down or come up. They are the official times listed in a reference book called the American Air Almanac, adjusted for your local area. Those official times are what the regulations actually use.
Context Anchor
Seen in FAA rules and planning items that depend on official daylight times, such as aircraft lighting requirements and deciding whether a flight occurs before or after the official daylight period.
Derivation
From Old English 'sunne' (sun) plus 'settan' (to set) and 'risan' (to rise). The simple visual image of the sun moving relative to the horizon directly supports the regulatory definition of when lighting and night-flight rules activate.
Why Pilots Care
Marks the legal start and end of night for required aircraft lighting and for logging night takeoffs and landings toward currency.
Intuition Check
Do not assume sunset and sunrise mean “when it looks dark” or “when it looks light” from the cockpit. In FAA use, they are official published times for a specific location, not personal estimates.
Example Sentence 1
Position lights must be on between sunset and sunrise as defined by the American Air Almanac for the aircraft's location.
Example Sentence 2
She scheduled the return flight to reach the airport before sunset to remain within day-VFR fuel reserves.