"Procedure N/A at Night" - What is "night"?

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thito01

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Planing a flight to an airport where the procedure is N/A at night. I will be arriving about 'sunset'.
If 'sunset' is defined as 16:39, 'civil twilight' as 17:06 and assuming that the approach would take 5 minutes to fly, what is the latest time that I can be 'cleared for the approach' by ATC?
 
thito01 said:
Planing a flight to an airport where the procedure is N/A at night. I will be arriving about 'sunset'.
If 'sunset' is defined as 16:39, 'civil twilight' as 17:06 and assuming that the approach would take 5 minutes to fly, what is the latest time that I can be 'cleared for the approach' by ATC?
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If it’s night you have to break off the approach, regardless of what ATC clears you for.

14 CFR 1.1 Definitions
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.

https://www.ecfr.gov/current/title-14/chapter-I/subchapter-A/part-1
 
This is a good question.

There are some big TRACONS in parts of the US. Sunrise/sundown times are going to vary 3 minutes east to west across a 30 nm mode C veil and >10 minutes east to west across some TRACON radar service areas. A80 cuts across all of GA into AL. I don’t believe it is the controller’s responsibility to watch the sundown clock for each of the airports.


TRACON map of the United States. This map shows the “local” airspace surrounding airports.
 
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Clip4 said:
This is a good question.

There are some big TRACONS in parts of the US. Sunrise/sundown times are going to vary 3 minutes east to west across a 30 nm mode B veil and 8 minutes east to west across a some TRACON radar service areas.
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It has nothing to do with what ATC clears you for. If it's night where you are, you can't fly on any segment of the approach.

If the approach is N/A'd by notam, and ATC clears you for the approach, you're still not legal to fly it.
 
There are three definitions of night in various portions of the regs. BradZ's is probably the most applicable here. It's one of my favorites because I was responsible for the revision of that passage in the regs (I filed a petition for rulemaking pointing out they had the name of the Air Almanac wrong for over a decade).
 
No matter the “official” definition, if it is too dark to see obstacles, I would not fly the approach. I think the terpsters expect a highly trained pilot to have good judgment. :)
 
Brad Z said:
It has nothing to do with what ATC clears you for. If it's night where you are, you can't fly on any segment of the approach.

If the approach is N/A'd by notam, and ATC clears you for the approach, you're still not legal to fly it.
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I agree, I don’t believe ATC will refuse to issue and it’s up to the pilot.
 
After reading why they mark the charts such, I had already decided that I would not fly it at dusk because I figured the chart people knew better than me and I am not based there. I just wanted to better understand the regs involved. I thought it would not be sunset but instead civil dark, but "what is night" can vary.
 
The FAA variously describes night starting at: sunset, civil twilight, an hour after sunset.

Right now here those times are 5:11PM, 5:39PM, and 6:11PM.

Amusingly (while not used by the FAA) there is also astronomical twilight (6:42) and nautical twilight (6:11).
 
thito01 said:
Planing a flight to an airport where the procedure is N/A at night. I will be arriving about 'sunset'.
If 'sunset' is defined as 16:39, 'civil twilight' as 17:06 and assuming that the approach would take 5 minutes to fly, what is the latest time that I can be 'cleared for the approach' by ATC?
Click to expand...

thito01 said:
After reading why they mark the charts such, I had already decided that I would not fly it at dusk because I figured the chart people knew better than me and I am not based there. I just wanted to better understand the regs involved. I thought it would not be sunset but instead civil dark, but "what is night" can vary.
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I think you are on the right track. If you are having to split hairs as to the definitions, best to avoid the situation. The reason for the "N/A" is not just administrative, there is a real risk to life safety. I would be hesitant to fly any approach marked as such unless I had decent daylight available. Even consider if you are IFR, the clouds will make it dark or at least dimly lit well before official sunset, civil twilight, or whatever definition you seek to apply to the term "night".
 
flyingron said:
The FAA variously describes night starting at: sunset, civil twilight, an hour after sunset.

Right now here those times are 5:11PM, 5:39PM, and 6:11PM.

Amusingly (while not used by the FAA) there is also astronomical twilight (6:42) and nautical twilight (6:11).
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Slight quibble, I believe there's only one definition of "night", and it's civil twilight (61.1). The other uses of "when it's dark outside", for navigation lights and for currency, don't redefine night, they just tell when the nav lights must be on or you have to be current.

midwestpa24 said:
The reason for the "N/A" is not just administrative, there is a real risk to life safety.
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More quibbling, since I guess I'm in the mood. Sometimes it is effectively administrative.

There are primarily two reasons for a procedure to be NA at night:
1) Unlit penetrations of the 20:1 visual surface that extends out from the end of the runway. Most typically, trees. During the day you can see them, at night you can't. They are tall enough to pose a danger, so the procedure is labeled NA at night.
2) No official obstacle survey for that runway end. This means there may be obstacles, or there may not be, but since it can't be determined to be clear, the procedure is assumed to have unlit penetrations and the procedure is marked NA.

With #2, there are many, many cases where the 20:1 visual surface probably IS clear, and night operations could be performed safely just fine, but with no survey there is no way to prove it. So, in essence, it's an administrative reason.

Of course, as the pilot you don't know if it's #1 or #2, so the smart pilot will assume it's #1 and not press his or her luck.
 
RussR said:
1) Unlit penetrations of the 20:1 visual surface that extends out from the end of the runway. Most typically, trees. During the day you can see them, at night you can't. They are tall enough to pose a danger, so the procedure is labeled NA at night.
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Cool thing about trees…if the runway lights flicker, you’re too low. ;)
 
flyingron said:
There are three definitions of night in various portions of the regs. BradZ's is probably the most applicable here. It's one of my favorites because I was responsible for the revision of that passage in the regs (I filed a petition for rulemaking pointing out they had the name of the Air Almanac wrong for over a decade).
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By the way, is there a link to the Air Almanac?

[Edit] I found one. It's a 48 MB download!

https://www.usno.navy.mil/USNO/library/2021-publications/air-almanac-2021/view
 
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RussR said:
...There are primarily two reasons for a procedure to be NA at night:
1) Unlit penetrations of the 20:1 visual surface that extends out from the end of the runway. Most typically, trees. During the day you can see them, at night you can't. They are tall enough to pose a danger, so the procedure is labeled NA at night.
2) No official obstacle survey for that runway end. This means there may be obstacles, or there may not be, but since it can't be determined to be clear, the procedure is assumed to have unlit penetrations and the procedure is marked NA.

With #2, there are many, many cases where the 20:1 visual surface probably IS clear, and night operations could be performed safely just fine, but with no survey there is no way to prove it. So, in essence, it's an administrative reason.

Of course, as the pilot you don't know if it's #1 or #2, so the smart pilot will assume it's #1 and not press his or her luck.
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Thanks for that info. The approach for my home field used to be authorized at night, and I haven't been able to see any reason why that is no longer the case.

In places where #1 is the source of the problem, could they just specify higher minimums at night?
 

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It is NOT ATC's responsibility to be aware of notes/restrictions regarding the approach, it's 100% on the pilot. This is definitively stated in the 7110.65 (FAA Order on ATC).
 
Palmpilot said:
Thanks for that info. The approach for my home field used to be authorized at night, and I haven't been able to see any reason why that is no longer the case.

In places where #1 is the source of the problem, could they just specify higher minimums at night?
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No. It's about after leaving minimums and continuing visually to land. Those rocks, trees and structures down there could care less what altitude you started at.
 
somorris said:
No matter the “official” definition, if it is too dark to see obstacles, I would not fly the approach. I think the terpsters expect a highly trained pilot to have good judgment. :)
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Nope, they just expect pilots to follow the procedure and the regulations.
 
luvflyin said:
No. It's about after leaving minimums and continuing visually to land. Those rocks, trees and structures down there could care less what altitude you started at.
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Since the airport is open to VFR traffic at night, it seems like there ought to be a way to work it out. San Francisco Bay is not a particularly hostile obstacle environment. Maybe a circling-only approach?
 
Palmpilot said:
Since the airport is open to VFR traffic at night, it seems like there ought to be a way to work it out. San Francisco Bay is not a particularly hostile obstacle environment. Maybe a circling-only approach?
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Yeah. I dunno the exact TERPy rules about it. Maybe the Visibilty Minimum has something to do with it. Were talking about KPAO here, right? VFR is 3 miles, that Approach is 1 mile. Maybe @RussR or @aterpster will chime in with more detail.
 
Palmpilot said:
Since the airport is open to VFR traffic at night, it seems like there ought to be a way to work it out. San Francisco Bay is not a particularly hostile obstacle environment. Maybe a circling-only approach?
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The evaluation of the 20:1 visual surface for a circling approach vs a straight-in approach are pretty much the same. So it doesn't matter what type of approach you're designing for.

The minimums don't matter either. The visual surface comes into play when you descend below MDA (meaning you are visual, have the runway in sight, and are descending to land). It's assuming you're trying to descend at a normal 3 degree glidepath from the MDA.

Lots of simplifications in the last two paragraphs, but that's the idea.

So, either there are unlit obstacles here, or there is no obstacle survey. Or possibly another reason like noise abatement, but those are the two primary reasons that apply in well over 90% of cases of "NA at night".

If the reason is "no survey", the airport could fund a survey to possibly resolve the issue.
 
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Well, what do you know - from the IFP Gateway:

upload_2021-12-10_16-7-21.png

The note was added on Amendment 2 effective 10/10/2019.
 
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This is an issue now for anyone wanting to fly into the rather busy KHHR. None of the approaches are available at night anymore, due to surface penetrations that the airport seems to not care about dealing with. The airport has an LPV approach with relatively high mins and the GP into the airport will not make you hit anything except the runway, but TERPS standards are what they are for a reason.
 
RussR said:
Well, what do you know - from the IFP Gateway:

View attachment 102628

The note was added on Amendment 2 effective 10/10/2019.
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Wow, thanks for digging that up!

Whether the City of Palo Alto would be interested in funding such a study, I have no idea. If they did fund a study, I wonder if it would help if an LPV version of the approach were published. The existing LNAV minimums allow descent to 453 AGL starting about five miles from the runway.
 
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I'm just going to throw out what should be obvious here, but maybe isn't. If an approach isn't available at night, it's pretty likely that's because clearance to obstacles on the ground, trees or terrain, requires visual separation to provide a reasonable margin of safety, for either the approach or the missed. To me that's also a hint that VFR operation at night at whatever that airport is might be a bit tricky. That's true of a couple of airports near here that are in or around mountains.
 
luvflyin said:
No. It's about after leaving minimums and continuing visually to land. Those rocks, trees and structures down there could care less what altitude you started at.
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Tell me it isn't so.:crazy:
 
Clip4 said:
I agree, I don’t believe ATC will refuse to issue and it’s up to the pilot.
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It depends. I talked a bit about this in my "NA at Night" article in IFR Magazine. The "Point 65" tells controllers that can issue clearances based solely on traffic considerations and it's up to the pilot to comply with restrictions. Among the examples of "yes you can clear" ¶4-8-1 is "Procedure not authorized at night…."

OTOH, despite being absolved, some controllers will take it upon themselves to refuse to clear a pilot for an approach which is not authorized. I've seen discussions by controllers espousing both the "I won't clear" and "not my problem" points of view.
 
I read the paragraph and while I agree that it puts an obligation on the pilot to comply with restrictive notes, I don't see it as absolving the controller of responsibility. Your thoughts?

"2. Approach clearances are issued based on known traffic. The receipt of an approach clearance does not relieve the pilot of his/her responsibility to comply with applicable
Parts of Title 14 of the Code of Federal Regulations and the notations on instrument approach charts which levy on the pilot the responsibility to comply with or act on an
instruction; for example, “Straight-in minima not authorized at night,”
 
PastZTL said:
I read the paragraph and while I agree that it puts an obligation on the pilot to comply with restrictive notes, I don't see it as absolving the controller of responsibility. Your thoughts?

"2. Approach clearances are issued based on known traffic. The receipt of an approach clearance does not relieve the pilot of his/her responsibility to comply with applicable
Parts of Title 14 of the Code of Federal Regulations and the notations on instrument approach charts which levy on the pilot the responsibility to comply with or act on an
instruction; for example, “Straight-in minima not authorized at night,”
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Responsible to who? For what? Are you talking about an accident that went to Litigation? An accident that was the result of a pilot flying an Approach in violation of it’s published limitations? I think it very likely a jury will find the FAA, aka deep pocket, at least somewhat at fault for their rules. But the Controller for following those rules??? But who knows what evil lurks in the heart of a Jury:dunno:
 
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luvflyin said:
Responsible to who? For what? Are you talking about an accident that went to Litigation? An accident that was the result of a pilot flying an Approach in violation of it’s published limitations? I think it very likely a jury will find the FAA, aka deep pocket, at least somewhat at fault for their rules. But the Controller for following those rules??? But who knows what evil lurks in the heart of a Jury:dunno:
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Might not get to a jury. The subject is a bit more complex but the government is generally immune from suits on policy creation.
 
PastZTL said:
I read the paragraph and while I agree that it puts an obligation on the pilot to comply with restrictive notes, I don't see it as absolving the controller of responsibility. Your thoughts?

"2. Approach clearances are issued based on known traffic. The receipt of an approach clearance does not relieve the pilot of his/her responsibility to comply with applicable
Parts of Title 14 of the Code of Federal Regulations and the notations on instrument approach charts which levy on the pilot the responsibility to comply with or act on an
instruction; for example, “Straight-in minima not authorized at night,”
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That's a good point. I think it's the very first sentence, in context with the whole subject area. ATC's obligation is to separate traffic. So it is generally within its rights to clear an airplane to do anything the pilot asks so long as traffic permits. But it's not as clear as I make it sound. I never practiced in the Federal Tort Claim Act arena.
 
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"Mr Doe, you said you knew the I-L-S runway two eight was not authorized at night. It was twelve fifteen in the morning and yet you cleared November one two three four for an approach you knew was no good."

I'm not talking about a note that changes the approach minimums, but instead an entire procedure that shouldn't be used.
 
PastZTL said:
"Mr Doe, you said you knew the I-L-S runway two eight was not authorized at night. It was twelve fifteen in the morning and yet you cleared November one two three four for an approach you knew was no good."

I'm not talking about a note that changes the approach minimums, but instead an entire procedure that shouldn't be used.
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Ah. I don't think the rule should be changed. I would be for a requirement that Controllers not initiate an Approach they know the pilot should refuse. Certainly not put one on the ATIS as the Approach in use. And a requirement to remind a pilot that requests one, that it is N/A at night. But to refuse to give the clearance if the pilot says he wants the Approach anyway, no, I do not think it should be refused.
 
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midlifeflyer said:
Might not get to a jury. The subject is a bit more complex but the government is generally immune from suits on policy creation.
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Probably a good idea. There could be suits 24/7 in every courtroom in the country with a backlog measured in decades:devil:
 
The reason that night is defined as it is in 1.1 "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." is because there is still light available to see and avoid obstacles up to that point. At sunset, the sky is still quite bright. ATC should not be denying an approach clearance simply because of it is near sunset. In most places in the lower 48, there is still about a half hour before night kicks in.
 
"But to refuse to give the clearance if the pilot says he wants the Approach anyway, no, I do not think it should be refused."

I would not clear you for an approach that I knew was not authorized, nor would I advise anyone else to. If FSDO asked you under what authority you used to request and fly an unauthorized approach, what would be your reply?
 
That makes sense.

In many states, drivers are required to use headlights 30 minutes after sunset until 30 minutes before sunrise. That pretty nearly coincides with civil twilight, in the lower 48.
 
NoHeat said:
That makes sense.

In many states, drivers are required to use headlights 30 minutes after sunset until 30 minutes before sunrise. That pretty nearly coincides with civil twilight, in the lower 48.
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Which makes zero sense. Yet, in California, whenever I must use my windshield wipers I must have my headlights on.
 
PastZTL said:
"But to refuse to give the clearance if the pilot says he wants the Approach anyway, no, I do not think it should be refused."

I would not clear you for an approach that I knew was not authorized, nor would I advise anyone else to. If FSDO asked you under what authority you used to request and fly an unauthorized approach, what would be your reply?
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I probably wouldn't do it. Unless I felt I should. Like it was a long way to the closest Approach that was authorized and I felt it would be safer to do this one rather than spend another half hour in the air to go do an Approach at another airport with 30 minutes less fuel. Maybe it's my home drome and I know it like the back of my hand and there ain't no obstructions down there that are gonna grab me. Could be the night N/A is not because there are obstructions down there. They just haven't done a survey to see if there are any. Yeah, I busted a FAR. What's FSDO gonna do. I dunno. Maybe they'll say ok, you understand what's going on and are safe. But ya broke the law so we gots to do something. Take this wings course and get an hour with a CFII. Or maybe they go nuclear and pull my ticket. None of that is going to change what I would do as a Controller. Law says pilots responsibility, not mine. I do not have the authority to deny it. Once again I wouldn't do it indiscriminately. I wouldn't initiate the Approach. I would advise the pilot it was not authorized at night. If he says I want to do it anyway, he's getting the Clearance.
 
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