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?

 

[A2J]

If the small is just landing, it's a caution WT. Approving a touch and go would require visual and caution (3-9-7 b3). In the unlikely scenario you can't get visual, then you just need 3 minutes (3-9-7 a2) since a touch and go is considered an intersection departure.

 

[HammerHead]

If the small is just landing, it's a caution WT. Approving a touch and go would require visual and caution (3-9-7 b3). In the unlikely scenario you can't get visual, then you just need 3 minutes (3-9-7 a2) since a touch and go is considered an intersection departure.

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.

 

[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.

 

[HammerHead]

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.

Approaches OR directly behind. Directly Behind is defined as following flight path of the lead aircraft over the surface of the earth. The cautionary from 3-10-3 is in addition to this.

 

[Acquired Taste]

Approaches OR directly behind. Directly Behind is defined as following flight path of the lead aircraft over the surface of the earth. The cautionary from 3-10-3 is in addition to this.

No, that's IFR separation. The separation between an A388 super arrival and a C172 doing pattern work is don't trade paint and a cautionary wake turbulence advisory.

 

[A2J]

Approaches OR directly behind. Directly Behind is defined as following flight path of the lead aircraft over the surface of the earth. The cautionary from 3-10-3 is in addition to this.

They do not reference each other. So, that doesn't make sense that "it's an addition".

5-5-4 is for approaches and aircraft in a radar environment. Not applicable to the pattern aircraft.

No, that's IFR separation. The separation between an A388 super arrival and a C172 doing pattern work is don't trade paint and a cautionary wake turbulence advisory.

Yessir

 

[HammerHead]

No, that's IFR separation. The separation between an A388 super arrival and a C172 doing pattern work is don't trade paint and a cautionary wake turbulence advisory.

I understand that it's in the radar separation section which is synonymous with IFR but wake turbulence affects everyone. You make a good point.

It doesn't make sense to me to have wake turbulence separation by minutes for departing VFR aircraft but on final it doesn't matter let them get blown away.

My question to you is, do you provide that separation between IFR aircraft or TO an IFR aircraft. Example, you have a IFR small on an instrument approach. Tower has a heavy in the pattern. They base their VFR heavy in front of your IFR small. Do you need to apply 6 miles of separation or does it not matter because the heavy is VFR?

 

[Acquired Taste]

I understand that it's in the radar separation section which is synonymous with IFR but wake turbulence affects everyone. You make a good point.

It doesn't make sense to me to have wake turbulence separation by minutes for departing VFR aircraft but on final it doesn't matter let them get blown away.

My question to you is, do you provide that separation between IFR aircraft or TO an IFR aircraft. Example, you have a IFR small on an instrument approach. Tower has a heavy in the pattern. They base their VFR heavy in front of your IFR small. Do you need to apply 6 miles of separation or does it not matter because the heavy is VFR?

Doesn't matter. That's tower's traffic. Technically there's nothing stopping them from basing the heavy right in front of your guy no matter how dumb it is, as long as they say caution wake turbulence to the IFR small of course!

Edit: so yes, the separation is only applied IFR to IFR.

 

[ManBearPig]

Doesn't matter. That's tower's traffic. Technically there's nothing stopping them from basing the heavy right in front of your guy no matter how dumb it is, as long as they say caution wake turbulence to the IFR small of course!

Edit: so yes, the separation is only applied IFR to IFR.

So that's not necessarily true. We went up to the top with this exact thing. If the heavy is in the pattern at a VFR tower, it's true. 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.

 

[rhombus]

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.

 

[HammerHead]

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.

View attachment 8484
View attachment 8485
View attachment 8486

I was digging and this is the same thing I found. You're exactly right, depends on what airspace you're in.

 

[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.

 

[rugbydog11]

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.

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

 

[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.

View attachment 8484
View attachment 8485
View attachment 8486

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!

 

[NotKC]

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.

There is no separation standard between ifr/vfr aircraft for class d operations. Regardless of the order they arrive. Generally speaking, vfr aircraft arriving to class d airports are not radar identified and you couldn't apply mileage based separation even if you wanted to.