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When does Night begin?


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OK, so usually I get my sunset hours at Airnav.com, which lists sunset and civil twilight. But is the time they list for twilight the end of that period and the beginning of official night?

 

Sunset is 21:03

Evening Civil Twilight 21:40

 

So twilight lasts from 21:03 through 21:40 and after that it's night?

 

Don't mean to be dense on this one but whenever someone mentions night to me, especially in the same conversation as regulations/rating my head starts to spin, and I do want to follow regulations.

 

HVG

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OK, so usually I get my sunset hours at Airnav.com, which lists sunset and civil twilight. But is the time they list for twilight the end of that period and the beginning of official night?

 

Sunset is 21:03

Evening Civil Twilight 21:40

 

So twilight lasts from 21:03 through 21:40 and after that it's night?

 

Don't mean to be dense on this one but whenever someone mentions night to me, especially in the same conversation as regulations/rating my head starts to spin, and I do want to follow regulations.

 

HVG

 

Dear HVG, "night" can be looked at in 3 ways. By definition in Part 1, the time that we must display/use position lights and can legally carry passengers and third, when we can fly to maintain/restore night currency.

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Dear HVG, "night" can be looked at in 3 ways. By definition in Part 1, the time that we must display/use position lights and can legally carry passengers and third, when we can fly to maintain/restore night currency.

 

Right. This is for ratings i.e. my night cross country "in night VFR conditions." So would that be 1 hour after sunset like it would be for currency for carrying passengers?

 

In the definitions section of the FARs night is defined as beginning at "the end of civil twilight."

Edited by Hovergirl
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Right. This is for ratings i.e. my night cross country "in night VFR conditions." So would that be 1 hour after sunset like it would be for currency for carrying passengers?

 

In the definitions section of the FARs night is defined as beginning at "the end of civil twilight."

 

HVG, for logging night time towards a rating it must meet the "Definition" in Part 1. Most Instructors will make sure it is very dark before you go and meets all areas. Mike

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Which twilight? Civil, nautical, or astronomical? They're all based on the position of the sun. You can log night time starting at 30 minutes past sunset, but for currency you can't start until an hour after. Twilight has nothing to do with it, practically speaking.

Edited by Gomer Pylot
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Yeah, an hour after sunset should cover my bases, and it should be good 'n dark by then. Thanks for the replies!

 

HVG

 

 

I use this site for definitions.

 

http://aa.usno.navy.mil/faq/docs/RST_defs.php

 

and this site for calculations

 

http://aa.usno.navy.mil/data/docs/RS_OneDay.php

 

The end of civil twilight has nothing to do with time after sunset, it is defined as when the center of the Sun is geometrically 6 degrees below the horizon.

 

Just in case you need to know.

 

Goldy

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Well, to be pedantic, it does have to do with time after sunset, because the earth rotates at a rather constant speed, and thus the time for the sun to get from the horizon to 6 degrees below it is pretty much constant. Yes, it's a position, but it takes the same amount of time to get to that position every day. :P BTW, that time is 24 minutes, so 30 minutes after sunset is after the end of civil twilight. An hour after sunset is in the middle of astronomical twilight. All this is very important to some people, but only of academic interest to most of us.

Edited by Gomer Pylot
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There are 3 different types of 'night' according to the regs:

 

1. When the sun sets - that's when the pos lights need to go on

 

2. Evening Civil Twilight - sun 6 degrees below the horizon (approx 30 mins after sunset) - that's when you can start logging night in your logbook

 

3. 1 hour after sunset - that's when you need to do your night currency (i.e. 3 takeoffs and landings in the previous 90 days to be able to carry pax at night)

 

So if you took off just as the sun set and did 3 takeoffs and landings and came back and shut down you could log 0.5 of night and not get your night currency.

 

Fly safe

 

Kris

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Gomer- yes it kinda does. The rotation is not EXACTLY the same, but I guess close enough for the FAA. And yes, the magnetic poles are swapping too, but probably not in my lifetime.

 

Many have never heard of the geophysical explanation so I figured I would mention it.

 

Wouldn't it be great if the FAA just had one definition and used it throughout? Nah, no fun.

 

Goldy

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After waiting til 1030pm to take off two weeks ago and not getting home and in bed until well after 130am for a "night" x-c flight, my answer to the original question is NOT EARLY ENOUGH!! :P

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I say we just fly to N. Alaska for the winter, plenty of night flights available then !

 

Heck Em, you're in Seattle already...you're almost there !

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I say we just fly to N. Alaska for the winter, plenty of night flights available then !

 

Heck Em, you're in Seattle already...you're almost there !

 

:lol: Seriously. And while we're at it, let's take an IFR ship...'cause we'll need it!! :P

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Well, to be pedantic, it does have to do with time after sunset, because the earth rotates at a rather constant speed, and thus the time for the sun to get from the horizon to 6 degrees below it is pretty much constant. Yes, it's a position, but it takes the same amount of time to get to that position every day.

 

Unless your latitude changes. to be Pedantic.

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Well, yes, the latitude and the date have a lot to do with it. The use of a fixed time after sunset is a compromise which works well enough. Otherwise we would have to use a table to find the end of twilight for every single location. That's actually easy enough to do if you have the right GPS, but for most people most of the time, a fixed time is close enough for government work.

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After waiting til 1030pm to take off two weeks ago and not getting home and in bed until well after 130am for a "night" x-c flight, my answer to the original question is NOT EARLY ENOUGH!! :P

 

Tell me about it! In the summer night doesn't start until too late, and in the winter you're never going to get clear enough weather. I think I got home around 2 last night. zzzz -_-

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Wouldn't it be great if the FAA just had one definition and used it throughout? Nah, no fun.

 

Goldy

 

Well, if they did that I have a sneaking suspicion the FAR/AIM would be about half its current thickness. Then where would all those lesson plans go? Think of the poor CFI's, Goldy! :lol:

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You all mention three reasons to know when night is and when sunset is. Another good reason is because some airports prohibit night operations. Two of which I am aware are Aspen, CO, and Put-In-Bay, OH. If a call to the airport does not yield an intelligent answer about when night is, then I would use the FAA definition in 14 CFR Part 1 and add a little time buffer in there to make sure I'm in compliance. Just a thought.

 

~Jeff

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There are not 3 definitions of night. There is one. Night starts at evening civil twilight. Period. Most commonly, as Gomer has stated, this is just rounded to "Half hour after sunset." That's it, that is NIGHT in the eyes of the FAA. Period. You can now log night. You can log (roughly) 365 hours a night flying each year without ever needing to be night current.

 

That is because to meet currency requirements to fly at night, you must do your 3 t.o. and landings at least 1 hour after (or before) sunset or sunrise. Notice this is not a definition of night, simply a requirement to meet currency. You also may not carry passengers past 1 hour after sunset unless you are current. You can carry passengers up to 365 hours a year at "Night" and never be current.

 

Position lights must be on from sunset to sunrise. No mention of night there either.

 

Sorry if my mood comes off a bit edgy. I've been dealing personally with some folks who have less than exact interpretations of other definitions and its been grating on me.

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That's not exactly my interpretation, but you're at least partially right. if you're flying under Part 135, in order to be PIC at night, which is any time after the end of civil twilight, you have to be current at night, which requires 3 takeoffs and landings to a complete stop in the past 90 days, and they must have been performed between one hour after sunset and before one hour prior to sunrise. You can't legally fly as PIC under Part 135 unless you meet the currency requirements. You can fly under Part 91 to get those requirements, but you can't fly at all, passengers or not, unless you are current. There are lots of things that are different between Part 91 and Part 135, and you have to know which part applies when.

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I admit I have no idea how part 135 is written. Part 91 states you may not fly more than 1 hour after sunset, with passengers, unless you are current. You are still allowed to fly that "30 minutes" between twilight and 1 hour after sunset, with passengers, even if you are not current in part 91. Since night is defined as Civil twilight, you can log up to a half an hour of night without currency as long as you're on the ground with any passengers before 1 hour after.

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There are not 3 definitions of night. There is one. Night starts at evening civil twilight. Period. Most commonly, as Gomer has stated, this is just rounded to "Half hour after sunset." That's it, that is NIGHT in the eyes of the FAA. Period. You can now log night. You can log (roughly) 365 hours a night flying each year without ever needing to be night current.

 

That is because to meet currency requirements to fly at night, you must do your 3 t.o. and landings at least 1 hour after (or before) sunset or sunrise. Notice this is not a definition of night, simply a requirement to meet currency. You also may not carry passengers past 1 hour after sunset unless you are current. You can carry passengers up to 365 hours a year at "Night" and never be current.

 

Position lights must be on from sunset to sunrise. No mention of night there either.

 

Sorry if my mood comes off a bit edgy. I've been dealing personally with some folks who have less than exact interpretations of other definitions and its been grating on me.

 

Dear Edgy,

 

I did not say there were 3 definitions of night. I said there were mentioned in previous posts 3 reasons to know when night is. ;)

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Dear Edgy,

 

I did not say there were 3 definitions of night. I said there were mentioned in previous posts 3 reasons to know when night is. ;)

 

 

Point taken. I'll try to drink a bit less coffee and calm down. :D

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HG, if you are not looking for the achedemic definition, but instead just wanted the TIME you can bolt from HIO, there is a chart in dispatch under the helicopter board where the "no off airport" map is.

 

 

And the chart that Gold posted is mighty helpful as well.

 

 

Sandy

(who super can't wait to do more night flights)

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Oh, Duh. :huh: Thanks, I'm usually so quick in-n-out of that room I hadn't noticed.

 

HG, if you are not looking for the achedemic definition, but instead just wanted the TIME you can bolt from HIO, there is a chart in dispatch under the helicopter board where the "no off airport" map is.

 

 

And the chart that Gold posted is mighty helpful as well.

 

 

Sandy

(who super can't wait to do more night flights)

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