Wake turbulence with pattern traffic

[creepstreets]

We had a scenario come up, and there was a bit of a debate regarding wake turbulence for an aircraft in the pattern.

We had a large that was on a visual approach to the runway on right downwind. At the same time, we had a small on left downwind in the pattern. The large turned base, and we pointed out the traffic to the small so that he could follow the large in to the runway. If the small did NOT get the large in sight, would the small require the 4 miles in trail behind the large in 7110.65 5.5.4I?

 

[ManBearPig]

Yes. How would you provide radar services as required if there is no radar identification?

A) Serious question, have you worked at tower in Class C and had pattern traffic? I have. And worked pattern traffic at it almost every day I was in the tower.

B) Where in "Class C Services" does it say "radar"?

Tower applied visual separation does not require a radar ID. Pilot applied visual separation satisfies 5-5-4 wake turbulence minima, as well as not operating directly behind the lead landing "wake generating" aircraft.

You think DAB is radar IDing the 18 Riddle aircraft in their pattern after every touch and go??

 

[PrisonMike]

We’re just going to ignore para 2-1-20 wake turbulence cautionary advisories in this tread.

Got it.

 

[Termine]

Tower applied visual separation does not require a radar ID.

False. False false false. "Visual separation may be applied when other approved separation is assured before and after the application of visual separation." If you don't have radar ID, you don't have visual separation (unless you can make it work using Chapter 6 rules).

You think DAB is radar IDing the 18 Riddle aircraft in their pattern after every touch and go??

Yes. I don't think they're issuing the "radar contact" phraseology, but if LC is radar certified (which they should be) then the aircraft are radar identified by application of 5-3-2a. Or heck, 5-3-2c and the crosswind turn.

 

[32andBelow]

False. False false false. "Visual separation may be applied when other approved separation is assured before and after the application of visual separation." If you don't have radar ID, you don't have visual separation (unless you can make it work using Chapter 6 rules).


Yes. I don't think they're issuing the "radar contact" phraseology, but if LC is radar certified (which they should be) then the aircraft are radar identified by application of 5-3-2a. Or heck, 5-3-2c and the crosswind turn.

Yah the center or tracon applies radar before the tower takes over visually

 

[MJ]

A) Serious question, have you worked at tower in Class C and had pattern traffic? I have. And worked pattern traffic at it almost every day I was in the tower.

No, you’re the only one. Also My dad can beat up your dad.

B) Where in "Class C Services" does it say "radar"?

If they are in the pattern at a Class C airport, they are receiving radar Class C services

yeah I cited a shitty source, sorry

Pilot applied visual separation satisfies 5-5-4 wake turbulence minima, as well as not operating directly behind the lead landing "wake generating" aircraft.

If they are in the pattern at a Class C airport, they are receiving radar Class C services, and that arrival needs wake separation with the heavy or large in the pattern.

how do you meet that requirement? would it be by radar identifying an aircraft so you can provide that radar separation, per chance?

You think DAB is radar IDing the 18 Riddle aircraft in their pattern after every touch and go??

they Have a scope to positively correlate an aircraft position to its target, so yes.


After_Victor your post was spot on

 

[Termine]

Yah the center or tracon applies radar before the tower takes over visually

We're talking about Class C pattern traffic here. A VFR departs and is in the pattern; they fly a tight downwind for whatever reason and their target gets close to the target of an IFR guy short final.

Class C services include separation between the IFR and the VFR. If someone asks LC "what separation were you using" of course they will say "tower visual." Again, visual separation (tower or pilot) requires the assurance of other separation before and after the visual separation. What separation was LC using before visual? Target resolution. Target resolution is a form of radar separation and requires that both aircraft are (or are about to be) be radar identified. How was the VFR pattern traffic identified? The TRACON sure as hell didn't identify them using 5-3-2a because the TRACON never received a rolling call. So LC has to have identified them somehow.

 

[A2J]

We're talking about Class C pattern traffic here. A VFR departs and is in the pattern; they fly a tight downwind for whatever reason and their target gets close to the target of an IFR guy short final.

Class C services include separation between the IFR and the VFR. If someone asks LC "what separation were you using" of course they will say "tower visual." Again, visual separation (tower or pilot) requires the assurance of other separation before and after the visual separation. What separation was LC using before visual? Target resolution. Target resolution is a form of radar separation and requires that both aircraft are (or are about to be) be radar identified. How was the VFR pattern traffic identified? The TRACON sure as hell didn't identify them using 5-3-2a because the TRACON never received a rolling call. So LC has to have identified them somehow.

I'd say SRS before and after visual

But I only work at a class D so my life isn't this complicated with WT

 

[ManBearPig]

We're talking about Class C pattern traffic here. A VFR departs and is in the pattern; they fly a tight downwind for whatever reason and their target gets close to the target of an IFR guy short final.

Class C services include separation between the IFR and the VFR. If someone asks LC "what separation were you using" of course they will say "tower visual." Again, visual separation (tower or pilot) requires the assurance of other separation before and after the visual separation. What separation was LC using before visual? Target resolution. Target resolution is a form of radar separation and requires that both aircraft are (or are about to be) be radar identified. How was the VFR pattern traffic identified? The TRACON sure as hell didn't identify them using 5-3-2a because the TRACON never received a rolling call. So LC has to have identified them somehow.

JFC. I'm going to ask this to you, too. Do you work at a tower in Class C airspace??

No one is saying radar contact to someone in the VFR traffic pattern. The aircraft is in sight the entire time. You are massively over thinking this.

And because someone posted in above, you can't just think "radar contact" in your head, and have it count. You have to say it.

 

[Termine]

I'd say SRS before and after visual

You can transition from SRS directly to tower visual if you have the inbound in sight from the moment the pattern guy leaves the runway. You're right, in many/most situations that will be the case. But I can come up with perfectly plausible and legal situations where you don't have the inbound in sight at the moment the VFR leaves the runway.

In Class C we must separate IFRs from VFRs. Defined minimum separation at all times, 500' or target resolution or visual, not just WT sep when the small is passing behind. Yeah, if the VFR has just rotated and the IFR is on a five-mile ILS then obviously they aren't going to hit. But "come on, obviously they aren't going to hit" is not an approved form of separation. Target resolution is an approved form of separation.

Do you work at a tower in Class C airspace??

Yes.

No one is saying radar contact to someone in the VFR traffic pattern.

I agree.

You have to say it.

I disagree. Proper application of 5-3-2a/b/c or 5-3-3a/b/c/d is necessary and sufficient to consider an aircraft radar identified. The identification process is entirely contained within those paragraphs. There is a separate requirement to "inform" the pilot when initial radar identification is established, but that is an informational requirement and nothing more. It does NOT have any procedural significance. Not saying "radar contact" will not lead to a loss; their radar identification is established as soon as you have completed one of the seven radar ID requirements.

 

[ManBearPig]

You can transition from SRS directly to tower visual if you have the inbound in sight from the moment the pattern guy leaves the runway. You're right, in many/most situations that will be the case. But I can come up with perfectly plausible and legal situations where you don't have the inbound in sight at the moment the VFR leaves the runway.

In Class C we must separate IFRs from VFRs. Defined minimum separation at all times, 500' or target resolution or visual, not just WT sep when the small is passing behind. Yeah, if the VFR has just rotated and the IFR is on a five-mile ILS then obviously they aren't going to hit. But "come on, obviously they aren't going to hit" is not an approved form of separation. Target resolution is an approved form of separation.

There's runway and anticipated separation....

Yes.


I agree.


I disagree. Proper application of 5-3-2a/b/c or 5-3-3a/b/c/d is necessary and sufficient to consider an aircraft radar identified. The identification process is entirely contained within those paragraphs. There is a separate requirement to "inform" the pilot when initial radar identification is established, but that is an informational requirement and nothing more. It does NOT have any procedural significance. Not saying "radar contact" will not lead to a loss; their radar identification is established as soon as you have completed one of the seven radar ID requirements.

In my experience, the FAA disagrees. I know because they wouldn't give me a time off award or even a reach around for wrangling in a 4 ship F16 flight which start burst, and did their best to hit a B1900. I forgot to say "radar contact" as I identified each primary. Why do we say "radar contact" to everyone in approach if we don't have too????

Glad to hear you aren't saying "radar contact" to each pattern plane. Man you would sound dumb.

Curious how you handle aircraft on an IFR flight plan, in the tower pattern. You keep them all 3 miles apart?

 

[Termine]

Why do we say "radar contact" to everyone in approach if we don't have too????

We do have to. But there are rules and there are rules. If I allow separation to decrease to 2NM—that's a loss. If I tell someone leaving the ramp to "Taxi via C" instead of "Taxi via B, C"—that isn't a loss. I am sorry that management got their undies in a bundle about you not saying it.

Curious how you handle aircraft on an IFR flight plan, in the tower pattern.

The same way I treat VFRs, right? I ensure approved separation. Except VFR-IFR is 500', target resolution, or visual; IFR-IFR is 1000', 3NM, or visual. So hell yes, if I don't have the inbound in sight then I keep them 3 miles apart. If I do have the inbound in sight then I don't have to, provided that I ensured other approved separation existed before I got them in sight. Just the same as in the VFR-IFR scenario.

And what separation did I ensure existed? Radar separation.
How was it legal for me to apply radar separation? Because I identified both aircraft.

 

[AB19]

MJ definitely didn’t work at a level 8 up down that’s a class Charlie with lots of military in the tower pattern what would he know about anything

 

[tmdarlan]

Im still stuck on the no wake turb in deltas… my facility is gona have some heated convos this week…

How are we getting around 3-9-6 and the arrival version? Deltas can still use time. And i argue if you got a certified tower display you can still use miles. Thats the whole point of it.

 

[rhombus]

Im still stuck on the no wake turb in deltas… my facility is gona have some heated convos this week…

How are we getting around 3-9-6 and the arrival version? Deltas can still use time. And i argue if you got a certified tower display you can still use miles. Thats the whole point of it.

3-9-6 is about runway separation and has nothing to do with airspace. You follow those rules regardless of what class of airspace you are in

 

[Termine]

3-9-6 is about runway separation and has nothing to do with airspace. You follow those rules regardless of what class of airspace you are in

Can you point to where the book says that?

I mean obviously you do it, I do it, we all do it. We provide same-runway sep because we have to and I'm not saying we shouldn't... but what's the textual justification for providing SRS between two VFRs at a Delta? Putting the pieces together, same-runway separation is a kind of separation. It's right there in the name. And according to the pilot/controller glossary, at a Delta there is no separation service provided between VFRs.

Just one of those things that they haven't gotten around to spelling out in the book because nobody has been annoying enough to force them to, I guess.

 

[MJ]

Can you point to where the book says that?

I mean obviously you do it, I do it, we all do it. We provide same-runway sep because we have to and I'm not saying we shouldn't... but what's the textual justification for providing SRS between two VFRs at a Delta? Putting the pieces together, same-runway separation is a kind of separation. It's right there in the name. And according to the pilot/controller glossary, at a Delta there is no separation service provided between VFRs.

Just one of those things that they haven't gotten around to spelling out in the book because nobody has been annoying enough to force them to, I guess.

There are services provided defined by airspace requirements, and services that are provided that are not defined by airspace requirements. Runway sep is a requirement regardless of airspace, and the "no separation service" you're referencing is in regards to airspace requirements.

 

[Termine]

Runway sep is a requirement regardless of airspace, and the "no separation service" you're referencing is in regards to airspace requirements.

I believe you from a common-sense and "everyone does it this way" standpoint. I'm not about to go to work and launch a VFR Twin Cessna with 2000-and-airborne behind a Skyhawk. Obviously.

But do you have a textual reference for that statement? 7110.65, 7210.3, ICAO PANS-ATM, anything?

 

[MJ]

7110.65 ch3, ch7; AIM ch 3-2; 14 CFR Subpart B
probably others...

 

[rhombus]

I believe you from a common-sense and "everyone does it this way" standpoint. I'm not about to go to work and launch a VFR Twin Cessna with 2000-and-airborne behind a Skyhawk. Obviously.

But do you have a textual reference for that statement? 7110.65, 7210.3, ICAO PANS-ATM, anything?

Runways are part of the earth and are not considered or included in airspace


“from the surface” not “including the surface”

 

[Somenewguy]

Runways are part of the earth and are not considered or included in airspace
View attachment 8629

“from the surface” not “including the surface”

This argument doesnt really hold up to scrutiny.

If you're 2000' from the runway threshold and airborne in a class delta, you are no longer on the surface, so I can land a 747 behind that Cessna right?

Or to put it another way, a landing aircraft can cross the runway threshold with another aircraft on the runway but as long as it's airborne I don't have to apply any separation?


Everyone claims the 7110 was written by lawyers but it was mostly written by a bunch of FAA management/staff support types who "fixed" problems haphazardly as they arose. It is written with the assumption that the person reading it can infer quite a bit of the practical application aspect and avoid using rules in situations where it would compromise safety. Unfortunately most people are kind of stupid so they find new ways to fuck things up while still thinking that theyre following the rules. As a consequence the rule book has to get bigger every year because it doesn't explicitly say what to do in every situation.