What is reasonable lateral separation?

At what distance do you think it is no longer a safe, reasonable distance? (read post before voting)

  • 2 mi

    Votes: 5 10.2%

  • 1 mi

    Votes: 14 28.6%

  • 1/2 mi

    Votes: 11 22.4%

  • 1/4 mi

    Votes: 6 12.2%

  • 1000 feet

    Votes: 6 12.2%

  • 500 feet

    Votes: 2 4.1%

  • 100 feet

    Votes: 2 4.1%

  • when I lose paint

    Votes: 3 6.1%
  • Total voters
    49
  • Poll closed .
Salty

Salty

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Salty
Assuming an organized event environment, like a fly-in, or something similar, but NOT formation. Lot's of planes coming and going at all times. You aren't talking to other planes to keep separation. There is no NOTAM for aircraft not participating in the event. The event is at a towered airport. Tower is controlling once you are in immediate vicinity - but they have no radar capability.

This question is specific to the period of time you are NOT in the pattern, only before and after entering or departing the pattern.

Let's only consider aircraft within 500 feet of your altitude.

What type of lateral separation would you consider safe / unsafe?
 
And no, this is not to support a whining thread about how someone violated my personal space. I'm just curious where people's comfort limits are.
 
Too much depends. Is there any closing velocity? Can both aircraft maintain visual contact with each other? Maneuvering or straight and level?
 
TCABM said:
Too much depends. Is there any closing velocity? Can both aircraft maintain visual contact with each other? Maneuvering or straight and level?
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That's kinda the point. All of those things can happen (or not happen). Since there is no NOTAM, you have to assume all of them are possible.
 
Salty said:
That's kinda the point. All of those things can happen (or not happen). Since there is no NOTAM, you have to assume all of them are possible.
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Honestly I’m stuck on the towered airport w/no radar piece of your question. My mind is stuck around an operaring D with traffic that’s inside the D but has not established comms w/tower. Seems kind of an edge case. Then there’s Oshkosh on the other end of the spectrum.

That’s why I say too much depends to be able to answer your question.
 
Going in the same direction as me? Don't rub paint.

Going in the opposite direction? Quarter mile seems reasonable to me.
 
TCABM said:
Honestly I’m stuck on the towered airport w/no radar piece of your question. My mind is stuck around an operaring D with traffic that’s inside the D but has not established comms w/tower. Seems kind of an edge case. Then there’s Oshkosh on the other end of the spectrum.

That’s why I say too much depends to be able to answer your question.
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You have comms to the tower, but not each other, and the tower could care less about you until you're in their airspace, and they have no radar, so you know as much as them anywho. The best info you are getting is listening to other people talking to tower.
 
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Also important is the speed of the aircraft involved.
 
Bob Noel said:
Also important is the speed of the aircraft involved.
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Completely variable. A normal GA day + an event with a normal distribution of varied GA aircraft.
 
I'm envisioning a Cirrus and a 206 converging and racing to get on a 5 mile final straight in.
Emotions are high as they determine who has the right of way... the lateral distance comfort zone has all but disappeared. The Cirrus is taking the lead and smirks at the 206 pilot with a firewalled throttle...he noses down to gain speed...

as I turn base in a 172..
 
DaleB said:
Going in the same direction as me? Don't rub paint.

Going in the opposite direction? Quarter mile seems reasonable to me.
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I've been weighing this comment. At first it sounded good, but the more I've thought about it, the less I agree with it. If someone is catching up to me, I have even less chance of seeing him as I do someone coming right at me. Granted, he has a better chance, but I'm not sure that makes the odds any better.

A higher closure rate certainly seems like more risk though.
 
If it’s the regular group pf guys who go to the weekly fly-out with at least 40 to 50 arrivals (and not uncommonly more than 100), and it’s somewhat in the same direction, about 300 yards. If it’s one of our local 141 schools, then being over the same county is usually too close.
 
ateamer said:
If it’s the regular group pf guys who go to the weekly fly-out with at least 40 to 50 arrivals (and not uncommonly more than 100), and it’s somewhat in the same direction, about 300 yards. If it’s one of our local 141 schools, then being over the same county is usually too close.
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Not a school, though students could certainly be in the mix. But also not people that fly together regularly.
 
The tower radar capability shouldn’t even be considered into the equation. In a class D it’s not used for separation. It’s primarily for situational awareness and help with traffic advisories.

Technically a NMAC is anything less than 500 ft away from another aircraft but in a tower environment, I see no problems getting within that. If I’m aware of the aircraft and I can maneuver to avoid wake turbulence, I don’t have any hard and fast sep rule. Only thing is, you get too close to an aircraft on final and don’t give tower a big enough gap, might find yourself getting sent around.
 
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This is obscure enough, and at the same time oddly-defined enough, that I'm having a difficult time understanding what you're asking for, or the particular scenario.

At the same time you're trying to generalize it, you also seem to be making it extremely specific.

Maybe I need more coffee?

I have an underlying feeling that you've got a very specific scenario/event in mind, but simply not wanting to say it, so as to not overly-define the discussion. T'ain't Oshkosh, I understand that much.

I do much of my flying in/out of Class-D airports, most either underlying or very near Class-B. (specifically, GYR and SDM (Phoenix, Goodyear, and San Diego Brown Field)).

GYR used to be a quiet place, and now it's swarming with Cirrii as the home of the newly-created United Aviate academy. I want to keep that traffic as far away from me as possible.

Is flying that much of a circus where you are in Floriduh?

I guess this is a long post for me to say - I dunno. My comfort level varies with the situation.
 
How many? If we're talking about 20 planes spread out over the morning, then I'm OK with closer as I can concentrate on that target. If dozens all entering D at the same time, and ADSB hits are everywhere, then give me a mile to be on the look out for NORDO/ Non ADSB / Amish.
 
Rgbeard said:
This is obscure enough, and at the same time oddly-defined enough, that I'm having a difficult time understanding what you're asking for, or the particular scenario.

At the same time you're trying to generalize it, you also seem to be making it extremely specific.

Maybe I need more coffee?

I have an underlying feeling that you've got a very specific scenario/event in mind, but simply not wanting to say it, so as to not overly-define the discussion. T'ain't Oshkosh, I understand that much.

I do much of my flying in/out of Class-D airports, most either underlying or very near Class-B. (specifically, GYR and SDM (Phoenix, Goodyear, and San Diego Brown Field)).

GYR used to be a quiet place, and now it's swarming with Cirrii as the home of the newly-created United Aviate academy. I want to keep that traffic as far away from me as possible.

Is flying that much of a circus where you are in Floriduh?

I guess this is a long post for me to say - I dunno. My comfort level varies with the situation.
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I think this is fair feedback. I am thinking of a specific situation, but the situation is a fairly generic one. A lot of traffic in and out, but not formally controlled in any way. I do not want to call out the specific event, which makes it more of a challenge to discuss.

I know for sure we could have done better at the event, I was very uncomfortable multiple times during the event, and I'm trying to collect data on it to present to the organizers to improve the situation the next time. I have collected vast amounts of adsb data and am trying to filter out the worst situations and am looking for parameters for that filter. The data I present will be anonymous, and I want to make sure they aren't used for punishment in any way. I just want to demonstrate the things that were happening so that they can be avoided in the future.
 
Salty said:
Let's only consider aircraft within 500 feet of your altitude.
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But within that range you or they could be ascending or descending, and you’d have a mix of high and low wing aircraft. “Same direction” is general and aircraft could still be converging; opposite direction is worse.

I think I’d want at least a half mile lateral separation. But then I’m a bit of a coward, and braver folk might be happy with much less.


upload_2022-10-10_13-27-53.jpeg
 
In a four hour period, the following occurred between flights arriving or departing from this airport:
  • 66 flights between 1 mi and 2 miles separation
  • 16 between 1/2 mi & 1 mile
  • 2 between 2000 ft & 1/2 mile
  • 3 between 1000 & 2000 feet
  • 1 < 1000 feet
This seems like something we should be avoiding. Especially when some of those flights included aircraft with no knowledge there was unusual activity in the area.
 
Salty said:
Assuming an organized event environment, like a fly-in, or something similar, but NOT formation. Lot's of planes coming and going at all times. You aren't talking to other planes to keep separation. There is no NOTAM for aircraft not participating in the event. The event is at a towered airport. Tower is controlling once you are in immediate vicinity - but they have no radar capability.

This question is specific to the period of time you are NOT in the pattern, only before and after entering or departing the pattern.

Let's only consider aircraft within 500 feet of your altitude.

What type of lateral separation would you consider safe / unsafe?
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Are you talkin' using ADSB but you don't see the other plane yet?
 
I saw a couple so close they scared the crap out of me. And I had a couple on ADSB that I could NOT see, which scared the crap out of me.
 
Salty said:
And I had a couple on ADSB that I could NOT see, which scared the crap out of me.
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I had that happen recently. I'm with you, as I really want to see them out the window!
 
3000 feet (1/2nm) would be my lowest common denominator answer. Most generalist pilots can't vis recce A/A range to save their lives. In fairness to the 787-cockpit CAVU panckage grabbers, the FAA doesn't require them to be worth a damn about ranging to what they are supposed to stay away from anyways, as a requirement for licensing.

Given the above numbers, 93% of the sample staying outside of 3000 feet in all combinations of awareness or non-awareness of the other, intent or lack of intent to stay at or inside said range, and accuracy or lack of accuracy in their own range assessment, is probably a win in my book given nobody died. Sure, it might be a worthy exercise in debriefing the sequence leading to the closest 6, certainly the closest 1. But the other 93% did alright. *shrugs*
 
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I've been close to trading paint and I do NOT like the feelings that kind of closeness produces.
Except when I am in close, and flying formation, I suck at guessing distances. For me, more is better.
 
Salty said:
In a four hour period, the following occurred between flights arriving or departing from this airport:
  • 66 flights between 1 mi and 2 miles separation
  • 16 between 1/2 mi & 1 mile
  • 2 between 2000 ft & 1/2 mile
  • 3 between 1000 & 2000 feet
  • 1 < 1000 feet
This seems like something we should be avoiding. Especially when some of those flights included aircraft with no knowledge there was unusual activity in the area.
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And?
 
DaleB said:
Going in the same direction as me? Don't rub paint.

Going in the opposite direction? Quarter mile seems reasonable to me.
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Pretty much this, if we are communicating, even if it is just a wing waggle to show I see you (obviously not the same direction scenario)
1/4 mile (1500 feet) seems pretty comfortable to me if we are not communicating, just because I want enough time to react if the other guy doesn't see me and turns in front of me.

This assumes same altitude., put a couple hundred feet of vertical separation and I am find with probably 500 foot horizonal separation.
But then I have a lot of time Gaggling in thermals with gliders (like the photo below, the camera make them look further way than they usually are)

Brian


preflight-gaggle-big.jpg
 
Unless you're the guy who gets compliments on the accuracy of his instruments and then it's like 15 miles.
 
TCABM said:
And?
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I’m not sure what you’re looking for. On one side We have people having heart attacks because someone turned final with an aircraft 3 miles out, but on the other having random planes less than a thousand feet away (who aren’t communicating to you) is no big deal?

thats the point. I’m trying to gauge what people think about it.
 
Ahh, it was turning downwind to base with an airplane on 2 miles final, and yes, if I don't see the other airplane I'm not happy. As far as distances I am comfortable with, it depends. I would say generally if someone is a mile away and I or ATC is not talking to them, then I am again not happy and most likely doing something about it. The faster I am going the greater the distance.

I just had an instance about a month ago, I was talking to ATC, another plane was VFR and talking to ATC. It was VMC. We were head on. I was 175 knots GS and he was 145. ATC told us about each other. We were separated by 500 feet. I picked him up visually about 2 miles out, he had me, it was over pretty quickly and I was fine with it.

This afternoon, called into the busy delta I use. Was given enter the left downwind for 23, report midfield. About 15 seconds later, the controller asked me to slow down, (I was 8 miles out) I was number 5 in sequence, the guy I was following was on the upwind. It was vmc, but the downwind was into a rain shower, so in flight visibility was pretty lousy, but at least 6 miles. I followed that guy at about 2 miles, but damned if I couldn't find him until he turned base to final.

So the answer is it depends.
 
What does talking to ATC have to do with it? They don't have radar, and it's not their job to keep you safe in this situation. In one case, I had a plane fly up behind me at the same altitude and the dot sat right on top of me no matter what I did. I called it out to the tower, hoping the other pilot would back off, but he didn't. I never did see him, and I have no idea if he saw me or not, but I wasn't happy about it. Tower gave us both the same exact instructions. Lot's of help they were.
 
So far, it looks like the majority thinks 1/4 mile is acceptable.

I'm not sure I've made the scenario clear though. We're not talking about planes you saw the whole time and maneuvered near. We're talking flying along and BAM - there's a plane right off your wing. Or ADSB shows it was there and you never saw it.
 
Salty said:
What does talking to ATC have to do with it? They don't have radar, and it's not their job to keep you safe in this situation. In one case, I had a plane fly up behind me at the same altitude and the dot sat right on top of me no matter what I did. I called it out to the tower, hoping the other pilot would back off, but he didn't. I never did see him, and I have no idea if he saw me or not, but I wasn't happy about it. Tower gave us both the same exact instructions. Lot's of help they were.
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In both situations I described they have radar, that's how the ATC controller knew to we were converging and how the tower controller knew I needed to slow down. I believe the tower controllers are radar certified, but not 100 % . It did occur to me that I should know that for sure. I'll ask them the next time I'm there.
 
A 1/4 mile is nuts unless you are in communication with the other aircraft.
 
PaulS said:
In both situations I described they have radar, that's how the ATC controller knew to we were converging and how the tower controller knew I needed to slow down. I believe the tower controllers are radar certified, but not 100 % . It did occur to me that I should know that for sure. I'll ask them the next time I'm there.
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Ok. It's not what I'm asking about in the poll though. Which is why I realize it means nothing.
 
Salty said:
I’m not sure what you’re looking for. On one side We have people having heart attacks because someone turned final with an aircraft 3 miles out, but on the other having random planes less than a thousand feet away (who aren’t communicating to you) is no big deal?

thats the point. I’m trying to gauge what people think about it.
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In that case, I stand by it depends. If you, as the operator, feels like something is unsafe, it’s incumbent on you to the pilot stuff, Mav and not count on somebody else doing it for you.
 
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