Class E airspace

F

flying_John

Filing Flight Plan
Joined
Jun 12, 2021
Messages
9
Display Name
Display name:
flying_Joe
I have some questions on Class E airspace.

1. Blue edge E airspace
Reviewing sectional charts, I didn' find Blue edges of E airspace except countries boundaries and a few in Montana and Idaho. Does that mean that most of USA Class E airspace starts at 1200AGL, 700AGL or surface?
If so, what's the benefit of designating the Blue edges of E airspcace in mountain area in Montana and Idaho? As most of those area's elevation is beyond 10,000ft, adding 1200AGL is almost close to 14,500ft.

2. E airspace around uncontrolled airports
Uncontrolled airports with ILS approach seem to have Class E from surface around them. Those without ILS but with RNAV or VOR approach have Class E from 700AGL. But RNAV approach MDA is lower than 700GL. For example, 98D@(Onida Municipal Airport) has E airspace from 700AGL.
RNAV MDA is 2140ft (261AGL). so how is safety of instrument flying in IMC in uncontrolled airspace below 700AGL ensured?

3. Take off from uncontrolled airports without IAP
Pilots are allowed to fly IFR from those airport obtaining their clearance over their phone. In this case, again IFR flying in uncontrolled airspce from liftoff upto Class E floor. Same question as above.
 
Talking the 48 CONUS, and looking at sectionals E airspace is floor of 1200 AGL up to 17,999/FL180. Where you see the magenta shading around uncontrolled fields the floor is 700. Those fields have (or should have) instrument approaches. The dashed magenta line around airport is E to the surface. The rare blue areas are where the floor is 14,500. Its just where there isnt much traffic and ATC doesnt exercise control.

Having an ILS doesn't get you E to the surface, other factors determine that. As far as being in G and uncontrolled while IFR safety is not ensured. ATC should let you know if there is traffic in the area, but when you are in G, you have to use your eyes. The assumption is that no one is flying in IMC in G. Doesn't matter if taking off or landing.
 
EdFred said:
Having an ILS doesn't get you E to the surface, other factors determine that. As far as being in G and uncontrolled while IFR safety is not ensured. ATC should let you know if there is traffic in the area, but when you are in G, you have to use your eyes. The assumption is that no one is flying in IMC in G. Doesn't matter if taking off or landing.
Click to expand...

Yes.

I operate out of a grass strip (8NC8) that is right on the edge of a Class C whose edge is also the boundary of surface Class E.

I’ll pickup my clearance in the air if I can maintain VFR while getting it. If not, I get a void time clearance on the ground. The clearance will include a heading or waypoint to fly towards when ‘entering controlled airspace’ which means 700’ in my case. I’m never turned directly into the surface Class E or the overlying Class C at 1700’. Once radar contact is established, I’m turned on to my course. It’s my responsibility to stay separated from any VFR traffic until in controlled airspace under IFR conditions (where it remains my responsibility to remain separated from VFR traffic). VFR traffic’s responsibility is to stay legal. ATC’s responsibility is to keep me separated from other IFR traffic whether in Class E or on the runway. Use of the advisory freq when appropriate is key for local VFR traffic separation.

So who might be flying VFR into 8NC8 underneath the 700 Class E? Me. I might make an IFR approach into a neighboring airport (KHNZ or KTDF), cancel at 700’ and fly home to 8NC8. Use of 122.9 is key to let the other me on the ground that we may be in conflict as I takeoff on a void time clearance. Of course ATC also knows I broke of the approach at say KHNZ, to land at 8NC8, so they would be inclined to pass that on but that’s not their responsibility as I understand it.

I think all that is legal and works as intended.


Sent from my iPad using Tapatalk Pro
 
Most US controlled airspace starts at 1200 feet AGL these days. As a result, they've removed most of the blue vignetting from the charts to get rid of cartographic clutter. In the past, you saw the 1200 zones only around the airways, but as things got busier they overlapped and some states mandated their entire state be in the 1200 foot zone. Stuff outside that (what little remains) is uncontrolled up to 14,500 where the old continental control area starts (you'll note that this is roughly higher than the tallest terrain in the country).

The 700 foot was and is a transition area to lower the controlled airspace around airports with instrument approaches. Then you have what used to be known as a Control Zone but is now known officially as (deep breath) Surface Area of Controlled Airspace Designated For an Airport (whew!). These bring controlled airspace to the ground around airports that have instrument approaches and weather reporting. This now includes the class E surface areas (red dashed lines), class D, and the surface areas of class B and C.

As you note, one big thing is that the weather minimums change in controlled airspace, but that's not to say you can't have IFR flight in class G. one The few places where you do have IFR ops there rely on see and avoid and big sky rules. Note the FAA has held in enforcement actions that while IFR clearances are not required nor available in class G, if you don't have a clearance for the abutting controlled airspace (it is near impossible to make a flight entirely in class G because you the class E floor is below the minimum IFR altitude) it is "careless and reckless."

Most air carrier operations occur at places with surface areas because the air carrier (and now possibly an AWOS) can provide the required weather reporting.

As already pointed out, you can have IFR operations at places without towers or controlled airspace, or even approaches. Departures I can call for a clearance (look up void time clearances) prior to taking off that covers my barging into the overhanging class E. Arrivals just require an alternate and the ability to get down visually from the minimum instrument altitude (or divert to the alternate).
 
flyingron said:
Then you have what used to be known as a Control Zone but is now known officially as (deep breath) Surface Area of Controlled Airspace Designated For an Airport (whew!). These bring controlled airspace to the ground around airports that have instrument approaches and weather reporting.
Click to expand...
To flesh out this statement, technically instrument approaches and a live weather observer prior to AWOS/ASOS. The reason for Control Zones used to be fairly obvious…FSS or airline service, mostly. There are some part-time Class E surface areas that make absolutely no sense until you realize that it’s active during the times around when the Beech 1900 or freight dog would land and takeoff 30 years ago.
 
flying_John said:
I have some questions on Class E airspace.

1. Blue edge E airspace
Reviewing sectional charts, I didn' find Blue edges of E airspace except countries boundaries and a few in Montana and Idaho. Does that mean that most of USA Class E airspace starts at 1200AGL, 700AGL or surface?
If so, what's the benefit of designating the Blue edges of E airspcace in mountain area in Montana and Idaho? As most of those area's elevation is beyond 10,000ft, adding 1200AGL is almost close to 14,500ft.

2. E airspace around uncontrolled airports
Uncontrolled airports with ILS approach seem to have Class E from surface around them. Those without ILS but with RNAV or VOR approach have Class E from 700AGL. But RNAV approach MDA is lower than 700GL. For example, 98D@(Onida Municipal Airport) has E airspace from 700AGL.
RNAV MDA is 2140ft (261AGL). so how is safety of instrument flying in IMC in uncontrolled airspace below 700AGL ensured?

3. Take off from uncontrolled airports without IAP
Pilots are allowed to fly IFR from those airport obtaining their clearance over their phone. In this case, again IFR flying in uncontrolled airspce from liftoff upto Class E floor. Same question as above.
Click to expand...
Like @flyingron said above, there was a time when 1200 foot floor Controlled Airspace was pretty much established in conjunction with Airways. A lot of the Lower 48 looked like this pic below from a current Sectional in Alaska. Then GPS was invented and we could Navigate direct to places. Not just via Airways established by Navaids like VOR’s. Because ATC can only provide Air Traffic Control in Controlled Airspace, it got complicated. Rule Making was made that started eliminating almost all of the pieces of Uncontrolled Airspace above 1200 AGL. There are still a few isolated pieces left. Those ones you see in Montana were a mistake. The weren’t there about a year ago. Then someone found some mistakes in the Rule Making I mentioned above and poof, they put them on the Chart. New Rule Makings were done to clean it up. If I remember right, they are due to appear on the August 23 Chart revisions. If you want a copy of what it once looked like, make it now. Ya got 2 days

EDIT: I remembered wrong. It couldn’t have been August 23. There was an August 12 revision and it didn’t show there. Next revision date is October 8

upload_2021-8-21_13-37-49.png
 
Last edited:
2. An ILS has nothing to do with Class E at the surface. Class E to the surface is usually associated with the FAA granting a Part 135 certificate to an operator on the airport.
Click to expand...

Part of the criteria is if there is a public interest on fields that do not have towers to provide such, an air carrier (135 or 121) among other criteria.
 
Bill Watson said:
Yes.

……Class C whose edge is also the boundary of surface Class E…
…..I’m never turned directly into the surface Class E…


Sent from my iPad using Tapatalk Pro
Click to expand...
I don’t think you really meant ‘surface’ here
 
luvflyin said:
The nearest E Surface area to 8NC8 is KDAN 35 miles away.

EDIT: disregard. There’s an E extension to KRDU’s C 4 miles away. @Bill Watson , is this what you were talking about?
Click to expand...

Yes and no. I was under the mistaken (?) impression that the area under the Class C shelf was Class E to the surface. Is that not the case?


Sent from my iPad using Tapatalk Pro
 
upload_2021-8-21_18-41-54.png
Bill Watson said:
Yes and no. I was under the mistaken (?) impression that the area under the Class C shelf was Class E to the surface. Is that not the case?


Sent from my iPad using Tapatalk Pro
Click to expand...
No. It’s what it would be if the C wasn’t even there. 8NC8 is just outside the 700 foot E space so it’s in 1200 foot E by default. If it was G it would look like this:
 
Last edited:
flyingron said:
Most US controlled airspace starts at 1200 feet AGL these days.
Click to expand...

Isn't it more correct to say 700ft? Class G is uncontrolled, but the 700ft is actually the lowest controlled airspace and just about any airport that has a IFR approach is going to protect the airspace down to 700 feet.
 
pfarber said:
Isn't it more correct to say 700ft? Class G is uncontrolled, but the 700ft is actually the lowest controlled airspace and just about any airport that has a IFR approach is going to protect the airspace down to 700 feet.
Click to expand...
Do airports with IFR approaches constitute “most U.S. controlled airspace”?
 
pfarber said:
Isn't it more correct to say 700ft? Class G is uncontrolled, but the 700ft is actually the lowest controlled airspace and just about any airport that has a IFR approach is going to protect the airspace down to 700 feet.
Click to expand...
Yeah. But he said “most.” There are many more square miles of 1200 foot floor E airspace than there are of 700 foot floor or Surface Area.
 
MauleSkinner said:
Do airports with IFR approaches constitute “most U.S. controlled airspace”?
Click to expand...

I'm gonna say yes. Re-read that sentence carefully, are there airports with published IFR procedures that don't have a 700ft transition area?

Looking at the sectional, the only airfields without the magenta haze are grass/pvt/heliport
 
The statement you made sayid "isn't it correct to say 700ft" in response to my comment that most class E starts at 1200.
And the answer to that is NO. The 700 foot transition area is much smaller in area than the vast amount of 1200' AGL class E area in the US. In metro areas there is a lot of overlapping transition areas yes, but taking something the area of a sectional as a whole, there's more 1200' stuff. And stuff that's higher than 1200 is an obscure footnote these days.
 
pfarber said:
I'm gonna say yes. Re-read that sentence carefully, are there airports with published IFR procedures that don't have a 700ft transition area?

Looking at the sectional, the only airfields without the magenta haze are grass/pvt/heliport
Click to expand...
Here’s a paved, publicly owned airport without an IFR Procedure and therefore without magenta haze. Christmas Valley, OR, 62S. There are others.
 
Last edited:
pfarber said:
I'm gonna say yes. Re-read that sentence carefully, are there airports with published IFR procedures that don't have a 700ft transition area?

Looking at the sectional, the only airfields without the magenta haze are grass/pvt/heliport
Click to expand...
luvflyin said:
Here’s a paved, publicly owned airport without an IFR Procedure and therefore without magenta haze. Christmas Valley, OR, 62S. There are others.
Click to expand...

I love when people make stuff up or pull crap out of their butt. Here's some more publicly owned airports in MI with pavement and no approach procedures and 1200 above them.
Y73, 50D, Y65, Y89, Y87, 5Y1, Y95, Y93, 51M, 9C8, D15, 98G, Y83
 
luvflyin said:
Like @flyingron said above, there was a time when 1200 foot floor Controlled Airspace was pretty much established in conjunction with Airways. A lot of the Lower 48 looked like this pic below from a current Sectional in Alaska. Then GPS was invented and we could Navigate direct to places. Not just via Airways established by Navaids like VOR’s. Because ATC can only provide Air Traffic Control in Controlled Airspace, it got complicated. Rule Making was made that started eliminating almost all of the pieces of Uncontrolled Airspace above 1200 AGL. There are still a few isolated pieces left. Those ones you see in Montana were a mistake. The weren’t there about a year ago. Then someone found some mistakes in the Rule Making I mentioned above and poof, they put them on the Chart. New Rule Makings were done to clean it up. If I remember right, they are due to appear on the August 23 Chart revisions. If you want a copy of what it once looked like, make it now. Ya got 2 days

EDIT: I remembered wrong. It couldn’t have been August 23. There was an August 12 revision and it didn’t show there. Next revision date is October 8
Click to expand...
I’m not sure when the cleanup happened in ND, but I noticed fairly recently that there was G to 14,500 MSL northwest of 9Y1 and, seeing this post today, I checked and found that it’s back to normal, G to 1200 AGL.

flying_John said:
I have some questions on Class E airspace.

1. Blue edge E airspace
Reviewing sectional charts, I didn' find Blue edges of E airspace except countries boundaries and a few in Montana and Idaho. Does that mean that most of USA Class E airspace starts at 1200AGL, 700AGL or surface?
If so, what's the benefit of designating the Blue edges of E airspcace in mountain area in Montana and Idaho? As most of those area's elevation is beyond 10,000ft, adding 1200AGL is almost close to 14,500ft.

2. E airspace around uncontrolled airports
Uncontrolled airports with ILS approach seem to have Class E from surface around them. Those without ILS but with RNAV or VOR approach have Class E from 700AGL. But RNAV approach MDA is lower than 700GL. For example, 98D@(Onida Municipal Airport) has E airspace from 700AGL.
RNAV MDA is 2140ft (261AGL). so how is safety of instrument flying in IMC in uncontrolled airspace below 700AGL ensured?

3. Take off from uncontrolled airports without IAP
Pilots are allowed to fly IFR from those airport obtaining their clearance over their phone. In this case, again IFR flying in uncontrolled airspce from liftoff upto Class E floor. Same question as above.
Click to expand...
I think that the key on IMC in uncontrolled airspace is that VFR traffic has to stay clear of clouds, so you have to be extraordinarily unlucky to crash into one if you pop out of the clouds between 700 AGL and minimums. For what it’s worth, LPV minimums are not always 250 AGL and maybe the airspace was set up around non-WAAS nonprecision approaches like NDB or LNAV.
 
iamtheari said:
I’m not sure when the cleanup happened in ND, but I noticed fairly recently that there was G to 14,500 MSL northwest of 9Y1 and, seeing this post today, I checked and found that it’s back to normal, G to 1200 AGL.


I think that the key on IMC in uncontrolled airspace is that VFR traffic has to stay clear of clouds, so you have to be extraordinarily unlucky to crash into one if you pop out of the clouds between 700 AGL and minimums. For what it’s worth, LPV minimums are not always 250 AGL and maybe the airspace was set up around non-WAAS nonprecision approaches like NDB or LNAV.
Click to expand...
There was a Rule Making that did designate the entire airspace within the State of North Dakota Class E from 1200 AGL. That one, and some others, were being done around the same time as others, particularly the ones in Montana. The ND one would have been being done at some level via Minneapolis Center. The big chunks in Montana at Salt Lake City Center. I spent some time on the phone with the Procedures Specialist at ZLA in few calls over the course of a few weeks as the Rule Makings were being done and put out for comment in the Federal Register. There were discrepancies in what was being proposed. It doesn’t surprise me that those didn’t get done by the last Chart Cycle.
 
pfarber said:
I'm gonna say yes. Re-read that sentence carefully, are there airports with published IFR procedures that don't have a 700ft transition area?

Looking at the sectional, the only airfields without the magenta haze are grass/pvt/heliport
Click to expand...
Re-read my post carefully…do those airports encompass “most US controlled airspace”?
 
iamtheari said:
For what it’s worth, LPV minimums are not always 250 AGL and maybe the airspace was set up around non-WAAS nonprecision approaches like NDB or LNAV.
Click to expand...
There has to be a reason other than what type of approach an airport has in order to designate a Class E surface area. Prior to alphabet airspace and AWOS/ASOS, it was the presence of a weather observer. Those airports generally still have Class E surface areas, and to include part time Class E based on the last observers’ work schedule.

I don’t know the current criteria for designating Class E surface areas, nor do I know of any that have been designated since the proliferation of AWOS/ASOS.
 
MrAnderson said:
I’m not sure what I’d do if KINK E wasn’t at the surface
Click to expand...
How about fly an approach like 1000s of others do each year that start at 700'???? Class E surface area has never been a consideration for going into or out of an airport.
 
MauleSkinner said:
There has to be a reason other than what type of approach an airport has in order to designate a Class E surface area. Prior to alphabet airspace and AWOS/ASOS, it was the presence of a weather observer. Those airports generally still have Class E surface areas, and to include part time Class E based on the last observers’ work schedule.

I don’t know the current criteria for designating Class E surface areas, nor do I know of any that have been designated since the proliferation of AWOS/ASOS.
Click to expand...
If I recall correctly, the two requirements are still weather reporting and the ability to contact ATC or FSS from the ground by radio. But those are base requirements and still don't tell us why one airport with both has a Class E surface area and another doesn't.

shot in the dark (more speculative than a WAG :D): I wonder whether a monitored ILS might be a factor. (Edit: Nope)
 
MrAnderson said:
I’m not sure what I’d do if KINK E wasn’t at the surface
Click to expand...
You might want to set a personal DA/MDA minimum above 700 AGL if you don’t want to worry about planes milling around down there Clear of Cloud with 1 mile visibility.
 
EdFred said:
How about fly an approach like 1000s of others do each year that start at 700'???? Class E surface area has never been a consideration for going into or out of an airport.
Click to expand...

KINK E… was actually a joke.
 
midlifeflyer said:
If I recall correctly, the two requirements are still weather reporting and the ability to contact ATC or FSS from the ground by radio. But those are base requirements and still don't tell us why one airport with both has a Class E surface area and another doesn't.

shot in the dark (more speculative than a WAG :D): I wonder whether a monitored ILS might be a factor. (Edit: Nope)
Click to expand...
At the end of the day, if someone considers it appropriate, it can be done. See 4. below.
Communication does not need to be by radio directly to ATC.

18−1−3. DESIGNATION
If the communication and weather requirements described in paragraphs 17−2−9 and 17−2−10 are met, Class E surface airspace may be designated to accommodate:
a. IFR arrival, departure, holding, and en route operations not protected by other controlled airspace.
b. Instrument approach procedures. Surface airspace may be designated to accommodate special instrument procedures if such action is justified and/or in the public interest. The following factors are among those that should be considered:
1. Type of procedure including decision height or minimum descent altitude.
2. The actual use to be made of the procedure, including whether it is used by a certificated air carrier or an air taxi/commuter operator providing service to the general public.
NOTE−For special instrument procedures, consideration should be given to availability to other users.
3. The operational and economic advantage offered by the procedure, including the importance and interest to the commerce and welfare of the community derived by the procedure.
4. Any other factors considered appropriate.

17−2−9. COMMUNICATIONS
Communications capability must exist with aircraft, that normally operate within the Class D Surface Area down to the runway surface of the primary airport (the airport upon which the surface area is designated). This communication may be either direct from the ATC facility having jurisdiction over the area or by rapid relay through other communications facilities which are acceptable to the ATC facility having that jurisdiction.
 
luvflyin said:
At the end of the day, if someone considers it appropriate, it can be done. See 4. below.
Communication does not need to be by radio directly to ATC.
Click to expand...
Not just someone, but someone interested in initiating the regulatory process followed by someone in system interested in pursuing it.
 
flyingron said:
The statement you made sayid "isn't it correct to say 700ft" in response to my comment that most class E starts at 1200.
And the answer to that is NO. The 700 foot transition area is much smaller in area than the vast amount of 1200' AGL class E area in the US. In metro areas there is a lot of overlapping transition areas yes, but taking something the area of a sectional as a whole, there's more 1200' stuff. And stuff that's higher than 1200 is an obscure footnote these days.
Click to expand...

I think we need to understand the word 'starts'. What controlled airspace starts at the lowest altitude? 700ft Transition areas.

The second lowest altitude for controlled airspace starts at 1200ft class e.

Maybe you are not seeing the nuance of the question?
 
pfarber said:
I think we need to understand the word 'starts'. What controlled airspace starts at the lowest altitude? 700ft Transition areas.

The second lowest altitude for controlled airspace starts at 1200ft class e.

Maybe you are not seeing the nuance of the question?
Click to expand...
The lowest controlled airspace is 0AGL. I'm not sure what point you are trying to make.
My initial statement that most US controlled airspace starts at 1200' is correct. THe answer to your question, "Isn't it 700?" is NO. Only a small amount of US airspace controlled airspace starts at 700.
 
You must log in or register to reply here.
Back
Top