Night time can be a little confusing, because not all of the FAA's night rules start at the same time. We'll explain the different time periods, and when you should use each one.

First off, there are three time periods you need to be familiar with to make sure you understand the FAA's night rules:

• Sunset to sunrise
• Your position lights need to be on (and anticollision lights if you have them)
• The end of evening civil twilight to the beginning of morning civil twilight
• You can log night flight time, and your plane needs to be night equipped
• 1 hour after sunset ending 1 hour before sunrise
• You need to be night landing current to carry passengers

Sunset to Sunrise

The FAA's night rules start when the sun sets. According to FAR 91.209, you need to have your position lights on from sunset to sunrise.

If you have anticollision lights, those need to be on too, unless you've determined it's in the interest of safety to turn them off (e.g. you're on the ramp or in clouds).

So when exactly are sunset and sunrise? ForeFlight has one of the easiest ways to look it up. Simply tap on your home airport, and the sunrise and sunset for the day are listed just below the airport's name.

The actual definition of sunrise and sunset is: "sunrise or sunset is defined to occur when the geometric zenith distance of the center of the Sun is 90.8333 degrees." That being said, we'd recommend you stick to your EFB.

For those of us without the measuring equipment for "geometric zeniths", sunset happens when you're standing at sea level with a level, unobstructed horizon, under average atmospheric conditions, and the upper limb of the Sun appears to be tangent to the horizon.

One note if you're flying in Alaska: the rules are a little different for you. The FARs say you need lighted position lights "during the period a prominent unlighted object cannot be seen from a distance of 3 statute miles or the sun is more than 6 degrees below the horizon."

Civil Twilight

Next up is civil twilight, and more specifically, when civil twilight ends.

The FAA's definition of night time is in Section 1.1 of the FARs. Here's what they have to say: "Night means the time between the end of evening civil twilight and the beginning of morning civil twilight, as published in the Air Almanac, converted to local time." If you fall in that time period, you can log night flight time, and your plane needs to be night VFR equipped.

So when exactly does civil twilight end (and begin)? You'll need to dig a little deeper here. The FAA references the Navy's Air Almanac. You can find civil twilight times on the Navy's website here.

According to the Navy's site, today at Rocky Mountain Metro Airport (KBJC) civil twilight ends at 6:31 PM, and begins again tomorrow morning at 6:58 AM. So if you're flying at KBJC, you can begin logging night flight time any time between 6:31 PM tonight, and 6:58 AM tomorrow morning.

How is civil twilight computed? Here's the Navy's definition: "civil twilight is defined to begin in the morning, and to end in the evening when the center of the Sun is geometrically 6 degrees below the horizon."

A good rule-of-thumb for calculating civil twilight is that it usually ends between 20-35 minutes after sunset. Tonight at KBJC, sunset is 6:03 PM, and civil twilight ends at 6:31 PM. That's a difference of 28 minutes.

1 Hour After Sunset To 1 Hour Before Sunrise

The last piece to night flying is logging your night landings, and carrying passengers with you. According to FAR 61.57(b), to carry passengers between 1 hour after sunset and ending 1 hour before sunrise, you need to make at least 3 takeoffs and landings to a full stop in the preceding 90 days during the period beginning 1 hour after sunset and ending 1 hour before sunrise.

So when is sunset? Just head over to ForeFlight, tap on your home airport to look up today's sunset, which at KBJC is 6:03 PM, and tack 1 hour onto it.

So if you need to get night current at KBJC tonight, you can start those takeoffs and landings at 7:03 PM.

Putting It All Together

As long as you're using your position and anticollision lights between sunset and sunrise, logging your night flight time after the end of civil twilight, and logging your night takeoffs and landings at least one hour after sunset, you're good to go.

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