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?

 

[rhombus]

I didn't say runways are airspace. I said your explanation of how things are doesn't make sense because same runway separation DOES include airborne aircraft.

All runway separation is based on markings or landmarks on the ground. The ground is the reference point. It doesn’t matter if one of the aircraft involved is airborne. Runway separation or lack thereof occurs on the ground

 

[A2J]

The large is an arrival not a departure. What you mention applies specifically to a intersection departure behind a departing aircraft.

5-5-4 H, is what applies to this situation. You would need 4 miles of separation if the succeeding aircraft comes within 2500 feet (directly behind) of the preceding aircrafts flight path.

99% of the time you are going to use pilot applied visual. As far as the rule goes he has to be directly behind (2500 feet of flight path). So base him once the large is over threshold. Even though the wake doesn't disappear, the separation requirement does.

You're right, that section I referenced was for a departing large.

I wanna say that 4-mile rule is for approaches though right? In 3-10-3 b2 just says throw a "caution WT" in there when it's same or parallel runways 2.5 or less for a small behind an arriving/departing B757/Large. That 4-mile rule is for approaches if I am not mistaken. It's in 5-5-4 g1. For sequencing purposes.

 

[Acquired Taste]

I stand corrected. I never realized those notes were in there to apply to 5-5-4 minima but that's pretty dumb. Let's take a look at DAB for example. You think when they have 10 in the pattern on 25L and a large is coming in on 25R, they just extend everyone so to next arrival after the large is 4 miles in trail? They are a class C and the runways are approx 1600 ft apart.

 

[rhombus]

I stand corrected. I never realized those notes were in there to apply to 5-5-4 minima but that's pretty dumb. Let's take a look at DAB for example. You think when they have 10 in the pattern on 25L and a large is coming in on 25R, they just extend everyone so to next arrival after the large is 4 miles in trail? They are a class C and the runways are approx 1600 ft apart.

I would hope not. Just establish pilot applied visual and they can get as close as they want

 

[Acquired Taste]

If they are in the pattern, and can't get pilot applied, it's time for them to full stop.

I would hope not. Just establish pilot applied visual and they can get as close as they want

Ahh I forgot about that part of the question. It's time for bed.

 

[MJ]

radar separation section which is synonymous with

They are not synonymous. Radar sep is a type of IFR sep.

do you provide that separation between IFR aircraft or TO an IFR aircraft

Separation service is always provided to an IFR aircraft. What those services are are dependent on things like airspace class and facility capability.

 

[HammerHead]

They are not synonymous. Radar sep is a type of IFR sep.


Separation service is always provided to an IFR aircraft. What those services are are dependent on things like airspace class and facility capability.

Ok I clearly don't know what synonymous means lmao that's not what I meant at all.

What I was mostly getting at with that is, in other than class B/C(I now know to specify), we supposedly do not have to provide wake turbulence separation to IFR if the preceding aircraft is VFR. Is this correct?

I'm generally asking because at this point I'm not sure.

 

[creepstreets]

It really depends what class of airspace you're working. Class B and C you would apply 5-5-4. Class D issue a wake advisory and just don't have a deal on the runway.

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This was the exact answer I was hoping for. Thanks! It IS still weird to me that in a class D, it just goes away and is fixed with a cautionary, but oh well!

 

[BDUB]

If you have a Large departing and a small on an instrument approach to the same runway and that small reports the large in sight on a 1 mile final can you give the spiel and give T & G clearance even though they can’t really mitigate their wake turbulence because they’re flying a established approach?

 

[SharDiNae]

If you have a Large departing and a small on an instrument approach to the same runway and that small reports the large in sight on a 1 mile final can you give the spiel and give T & G clearance even though they can’t really mitigate their wake turbulence because they’re flying a established approach?

If hes at 1 mile final id probably just hold the large and depart him after the small is gone. I have this same question though for if he was say 2/3/4 miles out. Maybe they give the small a missed heading to fly over the turbs. Can always say "go around" to take it in your own hands.

 

[MJ]

Ok I clearly don't know what synonymous means lmao that's not what I meant at all.

What I was mostly getting at with that is, in other than class B/C(I now know to specify), we supposedly do not have to provide wake turbulence separation to IFR if the preceding aircraft is VFR. Is this correct?

I'm generally asking because at this point I'm not sure.

It's not that you don't have to provide it, it's more like you can't provide it.

To exaggerate the point, think of an uncontrolled field. Do you have ANY idea of what's going on in that pattern where you would be able to provide separation to an IFR arrival? Same idea for a D tower. Towers' only separation responsibility for arrivals is the runway. Strip that tower down to it's basic function/capability and it's easy to see why it can't provide any sep.

And it's also a type of VFR sep, in those situations/airspaces where VFRs are provided separation.

 

[Acquired Taste]

It's not that you don't have to provide it, it's more like you can't provide it.

To exaggerate the point, think of an uncontrolled field. Do you have ANY idea of what's going on in that pattern where you would be able to provide separation to an IFR arrival? Same idea for a D tower. Towers' only separation responsibility for arrivals is the runway. Strip that tower down to it's basic function/capability and it's easy to see why it can't provide any sep.

I've never worked a class C but if someone is doing pattern work at a Class C airport, are they radar identified?

 

[darthmoses]

No D towers have a radar, they have certified tower displays.

Not all of us have radar. Speaking as a controller at one of the 2 FAA towers in the NAS that don’t. No traffic displays of any kind.

 

[rhombus]

No D towers have a radar, they have certified tower displays.

A tower in a C* provides radar services, so yeah they are positively id'd.

*there are exceptions, where the tower is within a C airspace but is a D surface area, so they don't provide radar services. pretty sure all usaf towers w/ approaches are like that

It might be the only one in the nation but Teterboro provides radar services

 

[AZNLUVR69]

No D towers have a radar, they have certified tower displays.

A tower in a C* provides radar services, so yeah they are positively id'd.

*there are exceptions, where the tower is within a C airspace but is a D surface area, so they don't provide radar services. pretty sure all usaf towers w/ approaches are like that

What if they departed from the the C airport to remain in the pattern? How are they radar identified? Can a tower only Class C controller radar identify aircraft?

 

[rhombus]

What if they departed from the the C airport to remain in the pattern? How are they radar identified? Can a tower only Class C controller radar identify aircraft?

You don't need a radar ticket to radar ID aircraft. Class B controllers do it every day.

I would only radar ID someone in a C if I were applying 5-5-4 for wake reasons

 

[MJ]

What if they departed from the the C airport to remain in the pattern? How are they radar identified? Can a tower only Class C controller radar identify aircraft?

Yes

 

[AZNLUVR69]

You don't need a radar ticket to radar ID aircraft. Class B controllers do it every day.

I would only radar ID someone in a C if I were applying 5-5-4 for wake reasons

Thanks. My old tower only Charlie we had VFR call ups and would radar ID them using primary and secondary methods, point out to approach, and sequence them in from the tower.

New tower Charlie tells me I can’t say “radar contact” or radar ID aircraft because I’m not “radar certified”. They force us to tell VFR call ups to contact approach? I don’t get it.

 

[MJ]

Thanks. My old tower only Charlie we had VFR call ups and would radar ID them using primary and secondary methods, point out to approach, and sequence them in from the tower.

New tower Charlie tells me I can’t say “radar contact” or radar ID aircraft because I’m not “radar certified”. They force us to tell VFR call ups to contact approach? I don’t get it.

FAA Up/Down?