Three different FAA “night” clocks
Pilots often treat “night” as one thing. The FARs use at least three different clocks, and they do not start and end at the same minute:
- 14 CFR 1.1 “Night” — the end of evening civil twilight to the beginning of morning civil twilight, as published in the Air Almanac. This is the definition used when you log night flight time.
- 14 CFR 61.57(b) night passenger currency — takeoffs and landings to a full stop, as the sole manipulator, during the period beginning 1 hour after sunset and ending 1 hour before sunrise, to carry passengers at night. Civil twilight is not the test.
- 14 CFR 91.209 position lights — from sunset to sunrise.
Civil twilight is the period when the sun is between the horizon and 6° below it. Evening civil twilight starts at sunset and ends when the sun reaches that minus-6° depression; morning civil twilight is the mirror image before sunrise. Logging night therefore starts later than sunset (after twilight has ended) and ends earlier than sunrise. Currency starts even later — a full hour after sunset — and ends a full hour before sunrise. Position lights, meanwhile, go on at sunset.
How the times are computed
This page uses the NOAA Solar Calculator algorithm (Jean Meeus, Astronomical Algorithms). Sunrise and sunset are computed for a solar zenith of 90.833° (the sun’s semi-diameter plus an average refraction). Civil twilight uses a zenith of 96°. The result is converted to the IANA time zone of the airport, or the zone you select, including daylight saving. The same events are also listed in Zulu.
Worked example
Los Angeles (approximately 34.05°N, 118.24°W) on a mid-summer day, Pacific Daylight Time:
- Sunrise is in the mid-5 o’clock hour PDT, sunset around 8 o’clock.
- Evening civil twilight ends roughly half an hour after sunset — that is when 1.1 night logging begins.
- 61.57(b) currency begins one hour after sunset, so later still, and ends one hour before sunrise the next morning.
- Position lights are due at sunset, earlier than either of the other two.
Frequently asked questions
When does night begin for logging flight time?
At the end of evening civil twilight, and it runs until the beginning of morning civil twilight (14 CFR 1.1). That is not sunset, and it is not the 61.57(b) window.
When can I log night takeoffs and landings for passenger currency?
During the period beginning 1 hour after sunset and ending 1 hour before sunrise (14 CFR 61.57(b)).
When do I need position lights on?
From sunset to sunrise (14 CFR 91.209).
How accurate is a sunrise time calculated from latitude and longitude?
The NOAA algorithm usually agrees with the Air Almanac to about a minute. Terrain and official publications still govern legal use.