CLASS D "extensions?"

luvflyin

luvflyin

Touchdown! Greaser!
Joined
May 8, 2015
Messages
16,235
Location
Santa Barbara, CA
Display Name
Display name:
Luvflyin
I've noticed that there are some Class D's that have extensions beyond the usual 4 nm. Usually these extensions are Class E Surface Areas, but in these cases they have actually extended the Class D. Is this done for some particular reason? It seems to be being done randomly. Is this the future? Are they in the process of extending Class D Airspace beyond the usual 4 nm radius all over the Country? There is one change that is already in effect by Notam, not charted yet (KSLE), where the Surface Area has been extended out beyond 8 nm and depending on how you read it, the whole thing could be Class D.

Examples I've found of "extensions" being Class D are, CSG MLU GGG SJT AEG MGE. By far a big majority of Class D's with extension still have the extensions as Class E Surface Areas. What's going on here?
 
luvflyin said:
I've noticed that there are some Class D's that have extensions beyond the usual 4 nm. Usually these extensions are Class E Surface Areas, but in these cases they have actually extended the Class D. Is this done for some particular reason? It seems to be being done randomly. Is this the future? Are they in the process of extending Class D Airspace beyond the usual 4 nm radius all over the Country? There is one change that is already in effect by Notam, not charted yet (KSLE), where the Surface Area has been extended out beyond 8 nm and depending on how you read it, the whole thing could be Class D.

Examples I've found of "extensions" being Class D are, CSG MLU GGG SJT AEG MGE. By far a big majority of Class D's with extension still have the extensions as Class E Surface Areas. What's going on here?
Click to expand...

It's to accommodate instrument approaches. Notice the extensions are aligned with runways.
 
Update from Oregon Pilots Assn. regarding the new Salem Class D:

Okay, the update on Salem airspace as of today [ed September 9, 2015]. Pressure from Merkley's and Schrader's offices along with a LOT of letters and emails to the FAA resulted in a LOA that will be signed today, temporarily suspending Class D airspace for a 3.5 mile radius around Independence. That takes the Delta boundary back to the river and allows full use of the pattern plus a straight out north and south departure on the runway heading. The FAA WILL reopen the NPRM process to allow public comment and we can go from there. I've now heard from the ag operators who are very upset. They begin harvesting Christmas trees in three weeks and that will be economically a hardship in class Delta with the visibility restrictions. I suggested they bring the growers' organizations into this fight. Got a minute? Got to our legislators' webpages and drop them a thank you note for their support for GA. They stepped up here. http://www.merkley.senate.gov/ http://schrader.house.gov/contact/
Click to expand...
 
Brad Z said:
It's to accommodate instrument approaches. Notice the extensions are aligned with runways.
Click to expand...

Those are often accommodated by class E surface areas. An eight nautical mile extension of class D seems like quite an airspace grab.
 
Palmpilot said:
Those are often accommodated by class E surface areas. An eight nautical mile extension of class D seems like quite an airspace grab.
Click to expand...

Some D's are bigger than others. I suspect because of jets.

Moffett and Long Beach are examples of rather big D's.

Extensions to accommodate instrument approaches can be either Class E or Class D.
 
Brad Z said:
It's to accommodate instrument approaches. Notice the extensions are aligned with runways.
Click to expand...

Yeah, I know. Surface areas take controlled airspace to the surface to keep the cloud clearance and visibility at 1000/500/2000 @ 3. The issue here is why are Class D surface areas starting to extend out in to where Class E Surface areas used to be and establishing the communication requirement.
 
Brad Z said:
It's to accommodate instrument approaches. Notice the extensions are aligned with runways.
Click to expand...

Yup. Final approach courses actually which are usually aligned with runways. It looks like they might be starting to be established in areas not associated with Instrument Approaches. Not only that, but being made Class D well beyond the usual 4 nm.
 
Palmpilot said:
Those are often accommodated by class E surface areas. An eight nautical mile extension of class D seems like quite an airspace grab.
Click to expand...

Yeah. Big grab. One of two things is probably happening here. Thats the intent and Class D's are going to start getting bigger everywhere in the future. Or something got lost in the translation here and the intent was to expand the Surface Area out and establish the Cloud Clearance and visibility requirement but somehow it got turned into Class D all the way out therefore establishing the communication requirement.
 
MAKG1 said:
Some D's are bigger than others. I suspect because of jets.

Moffett and Long Beach are examples of rather big D's.

Extensions to accommodate instrument approaches can be either Class E or Class D.
Click to expand...

Yeah. KLGB's is huge. KNUQ's seems normal, 4 miles.
 
Do the large(r) ones have radar? Seems like if you get much bigger than the standard class D, looking out the window with binoculars (if that's what they do, I have no idea) wouldn't work any more.
 
MAKG1 said:
Some D's are bigger than others. I suspect because of jets.

Moffett and Long Beach are examples of rather big D's.

Extensions to accommodate instrument approaches can be either Class E or Class D.
Click to expand...

Moffett's class D is 4.5 nm in radius. 4.3 nm (5 statute miles) used to be standard. Most of the class D areas in the Bay Area are smaller than normal. 4 - 5 nm appears to be typical for airports elsewhere.
 
Mistake Not... said:
Do the large(r) ones have radar? Seems like if you get much bigger than the standard class D, looking out the window with binoculars (if that's what they do, I have no idea) wouldn't work any more.
Click to expand...

I think they do. I have gotten requests to IDENT when calling KAPA. They don't have radar on site but they probably have surveillance radar feeds from Denver TRACON.
 
Flagstaff added on an extension a few years ago that is not lined to the runway
 

Attachments

  • image.jpg
    image.jpg
    135.5 KB · Views: 57
luvflyin said:
I've noticed that there are some Class D's that have extensions beyond the usual 4 nm. Usually these extensions are Class E Surface Areas, but in these cases they have actually extended the Class D. Is this done for some particular reason? It seems to be being done randomly. Is this the future? Are they in the process of extending Class D Airspace beyond the usual 4 nm radius all over the Country? There is one change that is already in effect by Notam, not charted yet (KSLE), where the Surface Area has been extended out beyond 8 nm and depending on how you read it, the whole thing could be Class D.

Examples I've found of "extensions" being Class D are, CSG MLU GGG SJT AEG MGE. By far a big majority of Class D's with extension still have the extensions as Class E Surface Areas. What's going on here?
Click to expand...

Classes of airspace cannot be created or modified except by rule-making. After the final rule is issued they do issue NOTAMs until the charting catches up.

As to Class D extensions as opposed to Class E Surface or transition extensions, that is a new one for me. I'll try to find the NPRM for KSLE when I have a chance.
 
IFR traffic in Class E airspace is controlled by ATC. The weather and speed restrictions make sure that IFR and VFR can see and avoid each other in Class E.

All airports with Class E surface areas are required to have a weather station and the ability for aircraft to contact ATC from the ground. This includes Class D with E to 700 and E to surface extensions.

The Class E airspace extension are there to protect IFR aircraft transitioning into or out of airport areas from enroute waypoints especially when weather minimums prevent VFR flight.
 
Last edited:
aterpster said:
...As to Class D extensions as opposed to Class E Surface or transition extensions, that is a new one for me...
Click to expand...

Here is what AIM 3-2-5d has to say about it:

Arrival extensions for instrument approach
procedures may be Class D or Class E airspace. As a
general rule, if all extensions are 2 miles or less, they
remain part of the Class D surface area. However, if
any one extension is greater than 2 miles, then all
extensions become Class E.​

If the SLE class D has been extended past 8 nm, that would appear to be an exception.
 
aterpster said:
Classes of airspace cannot be created or modified except by rule-making. After the final rule is issued they do issue NOTAMs until the charting catches up.

As to Class D extensions as opposed to Class E Surface or transition extensions, that is a new one for me. I'll try to find the NPRM for KSLE when I have a chance.
Click to expand...

Thanks, really appreciate it. Check out things like are they establishing Surface Area now to accomodate DP's as much as Approaches? In particular Diverse Vector Areas? If so do they really mean to make the whole Surface Area Class D? Do you have any way of finding out if Seattle Center runs KSLE single source off the Falls City ARSR
 
luvflyin said:
I've noticed that there are some Class D's that have extensions beyond the usual 4 nm. Usually these extensions are Class E Surface Areas, but in these cases they have actually extended the Class D. Is this done for some particular reason? It seems to be being done randomly. Is this the future? Are they in the process of extending Class D Airspace beyond the usual 4 nm radius all over the Country? There is one change that is already in effect by Notam, not charted yet (KSLE), where the Surface Area has been extended out beyond 8 nm and depending on how you read it, the whole thing could be Class D.

Examples I've found of "extensions" being Class D are, CSG MLU GGG SJT AEG MGE. By far a big majority of Class D's with extension still have the extensions as Class E Surface Areas. What's going on here?
Click to expand...

They're arrival extensions for instrument approaches. If all of the arrival extensions are less than two miles the extensions are supposed to be Class D airspace. If any arrival extension is more than two miles then all extensions are to be Class E airspace.
 
MAKG1 said:
Some D's are bigger than others. I suspect because of jets.

Moffett and Long Beach are examples of rather big D's.

Extensions to accommodate instrument approaches can be either Class E or Class D.
Click to expand...

A Class D or Class E surface area is supposed to be 3.5 miles in radius, plus the distance from the Airport Reference Point to the end of the outermost runway, rounded up to the next tenth of a mile. There may be some adjustments due to sloping terrain.
 
Last edited:
luvflyin - the NPRM talks about extending Class E surface and Class D out to 8+ miles. Does the NOTAM change this to Class D only?
 
luvflyin said:
Yup. Final approach courses actually which are usually aligned with runways. It looks like they might be starting to be established in areas not associated with Instrument Approaches. Not only that, but being made Class D well beyond the usual 4 nm.
Click to expand...

Four miles may be common but there is no fixed standard for Class D and E surface areas. See message #21.
 
Here is the new Salem (KSLE) Class D that went into effect August 20. It has created a lot of concern especially with regard to its impact on the busy Independence State Airport (7S5). Compare with the old configuration (2nd image).
 

Attachments

  • SLE.jpg
    SLE.jpg
    47 KB · Views: 48
  • SLE-old.jpg
    SLE-old.jpg
    92.1 KB · Views: 42
Last edited:
CRQ has a class E extension as well.. at least they did in the early 2000s
 
roncachamp said:
They're arrival extensions for instrument approaches. If all of the arrival extensions are less than two miles the extensions are supposed to be Class D airspace. If any arrival extension is more than two miles then all extensions are to be Class E airspace.
Click to expand...

Makes sense. Do you have a quotable source for that?
 
Mistake Not... said:
Do the large(r) ones have radar? Seems like if you get much bigger than the standard class D, looking out the window with binoculars (if that's what they do, I have no idea) wouldn't work any more.
Click to expand...

There is pretty good Radar coverage there. It's from the Center Radar by Falls City about 20 miles west. The Center runs the Approach control sevice there. Whether or not the Tower has a Radar display I don't know. The Tower is highly unlikely to have any IFR control authority delegated to them.
 
Mistake Not... said:
Do the large(r) ones have radar? Seems like if you get much bigger than the standard class D, looking out the window with binoculars (if that's what they do, I have no idea) wouldn't work any more.
Click to expand...

Some Towers have some IFR control authority and responsibility delegated to them, some do not. Some of them that do can use Radar separation, some cannot.
 
petrolero said:
I think they do. I have gotten requests to IDENT when calling KAPA. They don't have radar on site but they probably have surveillance radar feeds from Denver TRACON.
Click to expand...

Thats very common. Towers have many levels of use of Radar delegated to them. They range from being able to Radar Identify aircraft and then being able to use that for no more than making Traffic Calls to some IFR control authority.
 
d5by5 said:
IFR traffic in Class E airspace is controlled by ATC. The weather and speed restrictions make sure that IFR and VFR can see and avoid each other in Class E.

All airports with Class E surface areas are required to have a weather station and the ability for aircraft to contact ATC from the ground. This includes Class D with E to 700 and E to surface extensions.

The Class E airspace extension are there to protect IFR aircraft transitioning into or out of airport areas from enroute waypoints especially when weather minimums prevent VFR flight.
Click to expand...

Exactly. What we're noticing now is that a lot of what would use to have been Class E Surface Areas are now getting turned into Class D. And it appears that where Surface Areas pretty much use to be associated with protecting Approaches, it may now be just as much about Departures.
 
Palmpilot said:
Here is what AIM 3-2-5d has to say about it:
Arrival extensions for instrument approach
procedures may be Class D or Class E airspace. As a
general rule, if all extensions are 2 miles or less, they
remain part of the Class D surface area. However, if
any one extension is greater than 2 miles, then all
extensions become Class E.​
If the SLE class D has been extended past 8 nm, that would appear to be an exception.
Click to expand...

Yeah. Big exception. And the extension in question seems to have nothing do with "Arrival extensions for instrument approach
procedures" Thisone is not so much an "extension" as just an increase in radius.
 
JoeSelch said:
luvflyin - the NPRM talks about extending Class E surface and Class D out to 8+ miles. Does the NOTAM change this to Class D only?
Click to expand...

That Sir, is the big question. I've read it over and over again and it looks like maybe so. The reference to "extending Class E surface and Class D" may be about hours of operation of the Tower. Time will tell. My first take on it was no big deal. The inner 4 miles will Blue and the rest will be Magenta. But it's looking now like that may not be the case.

The simple fact that "surface area" is going out that far where no Approach course exists is a subject of discussion also. The crop dusters out there are crying Foul. I talked with someone I know who has a little general background information. Supposedly a half a year or so ago, Surface Areas and Diverse Vector Areas started getting into the ring together
 
roncachamp said:
Four miles may be common but there is no fixed standard for Class D and E surface areas. See message #21.
Click to expand...

Yeah. Got that. Those numbers are still pretty much in keeping with the intent of the old Airport Traffic Areas which got merged with the old Control Zones during the big ICAO alphabet soup airspace event in 1993(or so.) The Airport Traffic Area established a communication requirement and the Control Zone took controlled airspace to the surface. Those together became Class D. The Class E Surface Area had to be invented to cover the Control Zone extensions without establishing the communication requirement.
 
Pilawt said:
Here is the new Salem (KSLE) Class D that went into effect August 20. It has created a lot of concern especially with regard to its impact on the busy Independence State Airport (7S5). Compare with the old configuration (2nd image).
Click to expand...

Where did that image come from. Is there anything "official" about it? Or did someone just plug Lat Long coordinates into some Map App?
 
luvflyin said:
Thanks, really appreciate it. Check out things like are they establishing Surface Area now to accomodate DP's as much as Approaches? In particular Diverse Vector Areas? If so do they really mean to make the whole Surface Area Class D? Do you have any way of finding out if Seattle Center runs KSLE single source off the Falls City ARSR
Click to expand...

That would be a take a lot of my resources. I suggest you contact ZSE for the answer to your question.
 
luvflyin said:
Where did that image come from. Is there anything "official" about it? Or did someone just plug Lat Long coordinates into some Map App?
Click to expand...
I got that image from an OPA Facebook post. I'd cropped the image some, but the whole image shows it's from one of the flight planning apps.

Here's how Foreflight depicts the Class D now. The sectional chart hasn't been revised yet and still shows the old boundary, but click on it and FF depicts the new boundary.

At that same Facebook link above, OPA quotes the "Official Explanation" from Diane Fuller of FAA Renton:
Thank you for expressing your concerns regarding the recent airspace modifications to the Class D and E airspace around McNary Field (SLE) in Salem, Oregon. As background, the decommissioning of the ARTTY Fan Marker required Instrument Flight Procedures (IFP) to be amended at SLE. During the development of these amendments, it was discovered that a modification to the existing airspace was required to contain the IFPs. During our Safety Risk Management process, a need was identified to create a 1.2 mile cutout from Class D and E airspace to assist ingress and egress at Independence State Airport (7S5). With this modification, the airspace action was processed through the Notice of Proposed Rulemaking (NPRM) in the Federal Register with no comments being received. The airspace action became effective on August 20, 2015.
Click to expand...
(emphasis added)
 

Attachments

  • image.jpg
    image.jpg
    387.9 KB · Views: 29
Last edited:
aterpster said:
I presume the final rule was issued and has become effective.
Click to expand...
Here's the text from the A/FD Sectional Chart Bulletin effective 20 August 2015:
Revise SALEM, OR Class D: That airspace extending upward from the surface to and including 2,700 feet MSL within a 4-mile radius of McNary Field from the 330º bearing from the airport clockwise to the 074º bearing, and that airspace within a 6.2-mile radius of McNary Field from the 074º bearing from the airport clockwise to the 150º bearing, and that airspace within a 8.1-mile radius of McNary Field from the 150º bearing from the airport clockwise to the 330º bearing, excluding that airspace within 1.2 miles of Independence State Airport, OR. This Class D airspace area is effective during the specific dates and times established in advance by a Notice to Airmen. The effective date and time will thereafter be continuously published in the Airport/Facility Directory.

Revise SALEM, OR Class E: That airspace extending upward from the surface within a 4-mile radius of McNary Field from the 330º bearing from the airport clockwise to the 074º bearing, and that airspace within a 6.2-mile radius of McNary Field from the 074º bearing from the airport clockwise to the 150º bearing, and that airspace within a 8.1-mile radius of McNary Field from the 150º bearing from the airport clockwise to the 330º bearing, excluding that airspace within 1.2 miles of Independence State Airport, OR. This Class E airspace area is effective during the specific dates and times established in advance by a Notice to Airmen. The effective date and time will thereafter be continuously published in the Airport/Facility Directory.

Revise SALEM, OR Class E: That airspace extending upward from 700 feet above the surface within a 6.5-mile radius of McNary Field from the 330º bearing from the airport clockwise to the 074º bearing, and that airspace within a 8.2-mile radius of McNary Field from the 074º bearing from the airport clockwise to the 150º bearing, and that airspace within a 9.1-mile radius of McNary Field from the 150º bearing from the airport clockwise to the 330º bearing, excluding that airspace within 1.2 miles of Independence State Airport, OR.
Click to expand...
 
You must log in or register to reply here.
Back
Top