Class D

popaviator

popaviator

Well-Known Member
Talking with another cfi... Does class d change depending on what the tower sets up. Published everyone assumes that the radius is 4 miles, but can it be different?
 
I don't have a plotter on me, but I believe Terre Haute's (KHUF) airspace is larger than four miles.
 
The formula is R=D/6076+3.5

D = distance in feet from app/gp to EOR 3.5 miles =distance.
App/gp = airport reference point and or geographic position.


* my next question is where do you find the airport reference point? In the af/d?
 
Why do people even care about the "typical" dimensions. Each airspace (Class B, C, and D) is 'as depicted' and is taylor made for that specific area.
 
germb747 said:
Why do people even care about the "typical" dimensions. Each airspace (Class B, C, and D) is 'as depicted' and is taylor made for that specific area.
Click to expand...

If Im teaching a student I want him to have the best answer. So at the private level I'll tell him 4 miles typically. At a commercial level I would introduce the formula.
 
popaviator said:
If Im teaching a student I want him to have the best answer. So at the private level I'll tell him 4 miles typically. At a commercial level I would introduce the formula.
Click to expand...

I thought it was 4.4nm (5sm). Anyway, I've never heard of the "formula" until the post above. It's about as important to me as memorizing all the criteria the TERPSters use to design instrument approaches.

Nice to know, I guess, but the important thing is to know what the various classes of airspace are, what my responsibilities are with respect to that airspace, how to locate the airspace on a chart, and how to determine where I am in relation to that airspace.

Aside from knowing each airspace is configured to accomodate instrument approaches and requirements of the local area, I couldn't care less about how they designed the airspace.
 
popaviator said:
The formula is R=D/6076+3.5

D = distance in feet from app/gp to EOR 3.5 miles =distance.
App/gp = airport reference point and or geographic position.


* my next question is where do you find the airport reference point? In the af/d?
Click to expand...

Maybe but Ive never seen the ARP in the the AFD.

I know it is on the Airport Diagram in Jepp plates.
 
Also, if you zoom on on Patrick, you can clearly see the differences in the D airspace there.

http://www.runwayfinder.com/?loc=COF

If that isnt good enough for you just head down the coast and there will be all sorts of different sized D's. Generally they will be on the beach and only come out in good weather.

:)
 
A while ago TGray posted the document that showed all of the radiuses of "D" Airspace in the country.
I book marked it somewhere in my "FAA bookmarks" but it is way too late to go searching for it.

If you do a search on this website you will find it.
It didn't have anything to do with your formula but it is interesting and ties in to what you want to show your student. :beer:
 
What is the size of this class D

04119.jpg
 
popaviator said:
If Im teaching a student I want him to have the best answer. So at the private level I'll tell him 4 miles typically. At a commercial level I would introduce the formula.
Click to expand...
Why?

Just hanging around here, you can find knowledge gaps in basic things pilots should know among commercial pilots and CFIs. It would seem there is enough important stuff to teach without getting into trivial that's pretty much irrelevant unless you're sending the applicant to a DPE who happens to be a nut for such things.
 
Generally Class D is a 5NM radius around an airport extending up to 2,500 AGL (charted in MSL).

Obviously this can vary a great deal as I have only worked at one Class D tower that were these exact dimensions.

I've seen Class D tower's anywhere from 3.5 - 5 NM radius and from 1500 AGL to 2500 AGL.
 
Sure, if you are even in SW Connecticut look up KBDR. Next look up the bordering Sikorsky Heliport (JSD). Finally, move NW about 11 miles, and measure KDXR.

Three Class Deltas contained within a very small area, all with different shapes and sizes.
 
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