Class G above 1200 feet AGL

WDD said:
Good trivia point. A B C D E and G is what, 10 years old?

BONUS Question: Why no “F”?
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Alphabet Airpspace came to the US on September 16, 1993. The US never had the concept of class F. The Canadians have it, but they've perverted it from the ICAO meaning. They use it sort of like how we'd use Special Flight Rules Areas or Restricted Airspace. There's not a whole lot of it in Europe, either. Some in the UK. Class F officially is uncontrolled airspace where some IFR separation services are provided.
 
WDD said:
Ah - I was answering the question “can you get IFR clearance in E”.
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Sorry if my question wasn't clear. I should have put more emphasis on the word "anywhere" when I asked if you could get an IFR clearance anywhere in class E. What I was asking about was whether there are places in class E that you cannot get an IFR clearance for. If that is so, then it seems like this type of class G that has almost the same rules as class E could be reclassified as E but controllers just wouldn't give any clearances there. Other posts in this thread have answered the question of why that cannot be done. If that were done, IFR flights would not be allowed there. By leaving it as class G, IFR flights are allowed there (without clearance).
 
Larry in TN said:
What is IFR, the Instrument Flight Rules?

They are listed in 91.167 through 91.199. (The Visual Flight Rules are 91.151 - 91.165)

Look through the instrument flight rules for the rule (91.173) which requires an ATC clearance and see to what it applies.
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Thank you, Larry in TN, for providing interesting and useful information in response to my question about what guarantees separation between IFR airplanes flying in class G airspace. Unfortunately, after reading your response, I still don't understand how IFR airplanes are separated from one another in class G. As a VFR-only pilot, I suppose I don't really NEED to understand that, but I am curious. Are we just relying on the fact that the air is big and airplanes are small, so it is unlikely for two airplanes to be in the same spot at the same time, absent something like an airport or navaid that tends to funnel airplanes to a particular place?
 
TDGlider said:
I still don't understand how IFR airplanes are separated from one another in class G.
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ATC has no authority over flights in Class G airspace and can not provide separation services.

There are areas of the world where there are large sections of Class G airspace in which there is IFR traffic. There are situations like the area around Diego Garcia (FJDG), that I mentioned above, where IFR traffic advisories are provided for aircraft that choose to participate. There are also areas where there is a CTAF-like frequency where flights make blind position reports and listen for other traffic doing the same. I believe the latter is still in use in fairly large areas of Africa.
 

TDGlider said:
Sorry if my question wasn't clear. I should have put more emphasis on the word "anywhere" when I asked if you could get an IFR clearance anywhere in class E. What I was asking about was whether there are places in class E that you cannot get an IFR clearance for. If that is so, then it seems like this type of class G that has almost the same rules as class E could be reclassified as E but controllers just wouldn't give any clearances there. Other posts in this thread have answered the question of why that cannot be done. If that were done, IFR flights would not be allowed there. By leaving it as class G, IFR flights are allowed there (without clearance).
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There is so little Class G left in the Lower 48 above 1200 AGL that flying enroute there pretty much just isn’t done. Even though it’s Uncontrolled Airspace, there are still rules that must be followed. You have to be 1000 above terrain, 2000 in designated mountainous areas. And you have to comply with the hemispheric rule. Even Cardinal altitudes Westbound and odd Eastbound. So Westbound can’t be done. The only thing that can be done is Eastbound at 1000 where the terrain is 200 MSL or less

EDIT: What I said about it can’t be done Westbound is not true. My head was at close to sea level altitudes. But staying in the framework of there is so little G airspace that has a top more than 1200 AGL, as you go up in altitude, there is going to be the situation where you can only do it in one direction, but not the other. Read on.
 
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TDGlider said:
Sorry if my question wasn't clear. I should have put more emphasis on the word "anywhere" when I asked if you could get an IFR clearance anywhere in class E. What I was asking about was whether there are places in class E that you cannot get an IFR clearance for. If that is so, then it seems like this type of class G that has almost the same rules as class E could be reclassified as E but controllers just wouldn't give any clearances there. Other posts in this thread have answered the question of why that cannot be done. If that were done, IFR flights would not be allowed there. By leaving it as class G, IFR flights are allowed there (without clearance).
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E is Controlled Airspace so by basic rule you can get a Clearance. But there are situations where, because of other rules, it’s just not going to happen. Like through Prohibited Areas. Hot Restricted Areas. Hot Military Operating Areas.
 
The UK has for years allowed IFR in Class G IMC without ATC or separation, leading to some odd situations like ATC asking if the flight if it is IFR or VFR upon initial contact, although there’s supposed to be a special squawk code for IFR. There haven’t been any mid-airs as a result - there’s a lot of Class G but the IFR traffic density in these areas is very low. UK airspace and ATC is generally a mess of individual fiefdoms with limited coordination and lots of gaps, and this fits the pattern.
 
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TDGlider said:
Sorry if my question wasn't clear. I should have put more emphasis on the word "anywhere" when I asked if you could get an IFR clearance anywhere in class E. What I was asking about was whether there are places in class E that you cannot get an IFR clearance for. If that is so, then it seems like this type of class G that has almost the same rules as class E could be reclassified as E but controllers just wouldn't give any clearances there. Other posts in this thread have answered the question of why that cannot be done. If that were done, IFR flights would not be allowed there. By leaving it as class G, IFR flights are allowed there (without clearance).
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Well, it's always at ATC discretion to issue clearances. Not all airspace is above minimum instrument altitudes. Generally, you have to be one of the following:
1. Above the MEA/MOCA on an airway.
2. 1000 (2000 in mountainous) feet above everything within four miles of an off-airway route.
3. Above the MVA if you're getting radar vectors.

Below these (and not on a approach or proper departure), ATC will likely have issues unless you can guarantee your own terrain/obstacle clearance. Really, the sad fact is that they don't like to allow random routes below radar coverage. Some facilities (notably ROA for me), don't even like you to be on Airways above MEA but below the radar coverage. Apparenly, they are no better at non-radar procedures than most pilots are.
 
luvflyin said:
There is so little Class G left in the Lower 48 above 1200 AGL that flying enroute there pretty much just isn’t done. Even though it’s Uncontrolled Airspace, there are still rules that must be followed. You have to be 1000 above terrain, 2000 in designated mountainous areas. And you have to comply with the hemispheric rule. Even Cardinal altitudes Westbound and odd Eastbound. So Westbound can’t be done. The only thing that can be done is Eastbound at 1000 where the terrain is 200 MSL or less.
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What if the terrain is at 1500 and you cruise at 2000?
 
luvflyin said:
There is so little Class G left in the Lower 48 above 1200 AGL that flying enroute there pretty much just isn’t done. Even though it’s Uncontrolled Airspace, there are still rules that must be followed. You have to be 1000 above terrain, 2000 in designated mountainous areas. And you have to comply with the hemispheric rule. Even Cardinal altitudes Westbound and odd Eastbound. So Westbound can’t be done. The only thing that can be done is Eastbound at 1000 where the terrain is 200 MSL or less.
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flyingcheesehead said:
What if the terrain is at 1500 and you cruise at 2000?
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This is one of those "fun" CFI scenarios that I might break out once in a while to see how well a student can bring together all the associated rules - correlation, you know.

Using a local airport as an example (see graphic below), can I fly from HSD to JWG under IFR and stay in Class G airspace (and therefore not have to bother with that pesky ATC)?

We know we have to stay below 1200 AGL (700 at the start and end) to stay in Class G.
We know we have to cruise at even thousands.
We know we have to remain at least 500 feet away from people of structures, or 500 AGL (and above structures), or 1000 above the highest obstacle within 2000 feet, depending on what level of "congestedness" we think we are over.

Ground elevation is 1193 at HSD and 1551 at JWG.
So we have to cruise at 2000 (westbound, even thousands). There are no other options.

2000 is ~800 AGL at HSD but <500 at JWG.

On our climbout from HSD, we can't exceed ~1900 MSL until we're past the 700' Class E ring. Of course we can't level off at 1900 either, because then we're in cruise and that's not a valid cruising altitude (I would expect a debate about "necessary for takeoff and landing" here).

There are numerous obstacles (mostly windmills) NW of HSD that extend above 1500 MSL - so we can't overfly any of them at 2000 or we'd be less than 500 feet away. Of course, we're likely in the clouds so we can't see the obstacles anyway to tell if we're flying over them. And there is that 2283 tower that's just looking to get us if we try to fly around the south end of the windmill farm.

Once past Okarche, there's not much depicted on the map. But obstacles <200 feet high aren't usually charted, so you pretty much have to assume there are such obstacles everywhere (since again, we're in the clouds and can't see). As we get closer to JWG and the ground elevation rises to 1551, this becomes a problem with maintaining 2000 MSL AND being 500 feet from any structures (barns, houses, ham radio antennas, etc.).

Once we get to JWG, what do we do? We can't fly the approach (would require climbing into Class E), and we can't roll-our-own approach procedure. So we must make a contact approach, which means we must descend until we see the airport/runway. To do this, we must have at least 1 sm of visibility. I suppose descending from our cruise altitude to get below the clouds is okay as it's "necessary for takeoff and landing".

So could we do the flight? Theoretically, I think yes, barely. But practically, well, have fun, let me know how it goes because I won't be along for the ride!

I'm quite certain I missed some things here. Please let me know!

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RussR said:
This is one of those "fun" CFI scenarios that I might break out once in a while to see how well a student can bring together all the associated rules - correlation, you know.
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Ah, I love these. :D
RussR said:
Using a local airport as an example (see graphic below), can I fly from HSD to JWG under IFR and stay in Class G airspace (and therefore not have to bother with that pesky ATC)?
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Nope...
RussR said:
Ground elevation is 1193 at HSD and 1551 at JWG.
So we have to cruise at 2000 (westbound, even thousands). There are no other options.

2000 is ~800 AGL at HSD but <500 at JWG.
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Yup.
RussR said:
On our climbout from HSD, we can't exceed ~1900 MSL until we're past the 700' Class E ring. Of course we can't level off at 1900 either, because then we're in cruise and that's not a valid cruising altitude (I would expect a debate about "necessary for takeoff and landing" here).
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On the enforcement cases I've read, they really do seem to mean necessary. Not "necessary to keep from breaking the regs". So you'll need to have a bird that has terrible climb performance.
RussR said:
There are numerous obstacles (mostly windmills) NW of HSD that extend above 1500 MSL - so we can't overfly any of them at 2000 or we'd be less than 500 feet away. Of course, we're likely in the clouds so we can't see the obstacles anyway to tell if we're flying over them. And there is that 2283 tower that's just looking to get us if we try to fly around the south end of the windmill farm.
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And 91.177 says we need to be >1000 feet above any obstacle within 4nm of our course. I've been toying with a few different routes to get away from the windmills and various other things, and the highest clearance I've seen with an 8nm corridor is 318'. So we're not even close.
RussR said:
Once we get to JWG, what do we do? We can't fly the approach (would require climbing into Class E), and we can't roll-our-own approach procedure. So we must make a contact approach, which means we must descend until we see the airport/runway. To do this, we must have at least 1 sm of visibility. I suppose descending from our cruise altitude to get below the clouds is okay as it's "necessary for takeoff and landing".
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That was the other thing I found. No IAP without going into E, so while you could maybe be IFR if the obstacles weren't an issue, you couldn't be in IMC when you needed to start descending.

These class G exercises were a lot more fun when there was more G airspace above 1200 AGL.
 
@flyingcheesehead and @RussR , thx for speaking up. My ‘only when the terrain is less than 200 MSL remark was wrong. But within the framework of there’s so little G airspace that has a top less than 1200 AGL, as you move up in MSL altitudes of the surface, there is always going to be the point where you can do it in one direction but not the other because of the hemisphereic rule.
 
luvflyin said:
@flyingcheesehead and @RussR , thx for speaking up. My ‘only when the terrain is less than 200 MSL remark was wrong. But within the framework of there’s so little G airspace that has a top less than 1200 AGL, as you move up in MSL altitudes of the surface, there is always going to be the point where you can do it in one direction but not the other because of the hemisphereic rule.
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That's pretty much everywhere. I suppose you'd have to fly mostly north/south to find the right terrain height to be able to fly the desired direction. Kinda sounds like trying to fly a cross country to a specific destination in a hot air balloon!
 
flyingcheesehead said:
And 91.177 says we need to be >1000 feet above any obstacle within 4nm of our course. I've been toying with a few different routes to get away from the windmills and various other things, and the highest clearance I've seen with an 8nm corridor is 318'. So we're not even close.
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Yes! Thank you, I can't believe I forgot that one. In my defense, while I was typing this my daughter was lobbying me to have pizza for dinner. Spoiler alert - I said yes.

I could have saved myself a lot of time, because unless I'm figuring it wrong, 91.177 makes this scenario, and likely every other 1200' Class G IFR scenario, impossible in practice, except maybe over water.

In this scenario, we can only fly at 2000 MSL due to hemispheric rules. So the highest obstacle has to be no higher than 1000 MSL, which is BGL (below ground level!) in this area. Scenario done.

And in any other scenario, to cruise at 2000 MSL the ground would have to have to be no lower than 800 MSL (to be less than 1200 AGL), and no higher than 1000 MSL (for you to be 1000 ft above it).

But then there's the question of obstacles. The rule doesn't actually say "charted obstacle", it just says "obstacle". I don't see "obstacle" defined in 14 CFR 1.1, but in the TERPS world it's literally anything, including the terrain itself. So, antenna towers, buildings, trees, fence posts, grain silos, water towers, boats, power lines, anything.

So I suppose if you could find a route that you've personally surveyed for obstacles, where the ground elevation is 800-1000 MSL and no obstacles exceed 1000 MSL within 4 nm of your route, you could do it, theoretically. But that's an extremely narrow list of specifications. And of course you could only fly it westbound.

Add or subtract 1000 ft at a time for other cruising altitudes.
 
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RussR said:
Yes! Thank you, I can't believe I forgot that one. In my defense, while I was typing this my daughter was lobbying me to have pizza for dinner. Spoiler alert - I said yes.

I could have saved myself a lot of time, because unless I'm figuring it wrong, 91.177 makes this scenario, and likely every other 1200' Class G IFR scenario, impossible in practice, except maybe over water.

In this scenario, we can only fly at 2000 MSL due to hemispheric rules. So the highest obstacle has to be no higher than 1000 MSL, which is BGL (below ground level!) in this area. Scenario done.

And in any other scenario, to cruise at 2000 MSL the ground would have to have to be no lower than 800 MSL (to be less than 1200 AGL), and no higher than 1000 MSL (for you to be 1000 ft above it).

But then there's the question of obstacles. The rule doesn't actually say "charted obstacle", it just says "obstacle". I don't see "obstacle" defined in 14 CFR 1.1, but in the TERPS world it's literally anything, including the terrain itself. So, antenna towers, buildings, trees, fence posts, grain silos, water towers, boats, power lines, anything.

So I suppose if you could find a route that you've personally surveyed for obstacles, where the ground elevation is 800-1000 MSL and no obstacles exceed 1000 MSL within 4 nm of your route, you could do it, theoretically. But that's an extremely narrow list of specifications. And of course you could only fly it westbound.

Add or subtract 1000 ft at a time for other cruising altitudes.
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I've never considered flying nap-of-earth IFR as a serious pursuit, so I had forgotten until reading this thread that only 91.159 (VFR) says "more than 3,000 feet above the surface" while 91.179 (IFR) does not. You could possibly plot some kind of route in the vicinity of L06 where the Class E floor is above 1,000 MSL and the ground is below 0 MSL so you could go eastbound IFR at 1,000 MSL in uncontrolled airspace, but you'd have to be pretty crafty with topographic maps to be sure that the ground within 4 nm on both sides of your route is entirely below sea level while the centerline is no more than 200 feet below it.
 
Larry in TN said:
I've flown a DC8 IFR into an airport around which the floor of controlled airspace was FL245.

As you imply, there used to be a lot of Glass G below 14,500' in the western US. Someone learning to fly today would have no idea that it ever existed.
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I remember being shown a sectional from out west during training (late 70s). It looked very strange as there was no tint to show controlled airspace. The colors were much brighter. :D
 
Pinecone said:
I remember being shown a sectional from out west during training (late 70s). It looked very strange as there was no tint to show controlled airspace. The colors were much brighter. :D
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When I was teaching, I kept a supply of sectionals that included remote area, GCN SFAR airspace, etc. to use when teaching the use of sectionals. Had a WAC chart, too. You can teach the symbology without a chart but it isn't going to make sense and probably won't be remembered.
 
Larry in TN said:
I mentioned flying DC8s into an airport where the floor of controlled airspace is FL245. That is Diego Garcia (FJDG) in the Indian Ocean.
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Larry, I had the distinction of making the first emergency landing at Diego Garcia, in 1972. At the time of that flight, they were building the runway, and it was, if I remember right, around 4,000 feet finished. Taking off quite heavy toward the construction area, our C-130 settled out of ground effect and hit 11 metal grade stakes, puncturing the fuselage near the cargo ramp. That prevented pressurization, and we couldn't make it to Bangkok unless we could get into the flight levels. It's a long story, but we ended up landing back at Diego Garcia, quite heavy, and managed to stop on the pavement.
 
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