Class C/D effective hrs

[dukeblue219]

See Shaw AFB below. Class C with a class D area depicted as well. I assume that it is one or the other depending on time of day. But, per the AFD (look towards the bottom of second image) the hours of class D service are the same as the hours TWR is closed. So it's a class C most of the day, but when TRACON and TWR close at 0430z it becomes class D and not class E/G?

 

[warthog1984]

Yup .

 

[MAKG1]

Class D does NOT mean you must contact Tower. It means you must contact the ATC unit responsible for the airspace. Probably Shaw Approach in this case.

It appears the airspace shrinks when the tower is closed.

 

[kkoran]

Class D does NOT mean you must contact Tower. It means you must contact the ATC unit responsible for the airspace. Probably Shaw Approach in this case.

It appears the airspace shrinks when the tower is closed.

Note that the approach control operates the same hours as the tower.

 

[BillTIZ]

Class D does NOT mean you must contact Tower. It means you must contact the ATC unit responsible for the airspace. Probably Shaw Approach in this case.

It appears the airspace shrinks when the tower is closed.

Shaw Appch has the same hours as the Tower.
Contact Jax center when Tower/Approach is closed.

 

[kkoran]

It would be interesting to know why the Class D is effective when the tower is closed. I wonder what the controller at JAX ARTCC would do if someone called requesting transition through the Class D?

 

[poadeleted20]

It would be interesting to know why the Class D is effective when the tower is closed

Because unless something has changed, Shaw AFB it the home of an active duty USAF F-16 wing, and they probably don't want people futzing around over their operation at night without somebody knowing about it.

 

[Captain]

I think you guys are missing the Forrest for the trees.


Class D reverts to E when tower closes. Class C does not. So they set up class C airspace for when approach and tower are up and need something to protect it when they go home so they make a class D inside which is really just going to force the E to the floor.

That's my guess.

 

[dukeblue219]

Class D reverts to E when tower closes. Class C does not. So they set up class C airspace for when approach and tower are up and need something to protect it when they go home so they make a class D inside which is really just going to force the E to the floor.

That's my guess.

The basis of my question was "If this class C becomes a D when the tower/tracon are closed, then who owns the D space?" I have not come across airspace that was active Class D without a functioning tower.

As kkoran mentioned, it does seem weird that ARTCC would be responsible for a class D airspace, but certainly Ron is on the right track given that Shaw is a big-time F-16 base with no mixed civilian use. I would think you could leave it as class C overnight and put it in the hands of Jacksonville just as easily as converting to a towerless class D.

 

[Captain]

You're missing my point.

What happens to class C when tower closes? Nothing, class C towers don't close. So if you're a military installation who wants to close your tower at night and don't want uncontrolled airspace then the easy fix is to put a class D inside.

During the day the class C trumps the D. At night the class D reverts to class E and you end up with a class C airspace that can close at night and there always being controlled airspace over the field.

So, in effect you have a charted class D that never really exists.

 

[roncachamp]

Class D reverts to E when tower closes.

Some do. Some become Class G.

Class C does not.

I know of no part-time Class C airspace area that does not become Class E airspace when tower and approach close.

So they set up class C airspace for when approach and tower are up and need something to protect it when they go home so they make a class D inside which is really just going to force the E to the floor.

How would making it Class D protect it?

 

[roncachamp]

You're missing my point.

What happens to class C when tower closes? Nothing, class C towers don't close. So if you're a military installation who wants to close your tower at night and don't want uncontrolled airspace then the easy fix is to put a class D inside.

During the day the class C trumps the D. At night the class D reverts to class E and you end up with a class C airspace that can close at night and there always being controlled airspace over the field.

So, in effect you have a charted class D that never really exists.

They do.

 

[kkoran]

Because unless something has changed, Shaw AFB it the home of an active duty USAF F-16 wing, and they probably don't want people futzing around over their operation at night without somebody knowing about it.

If that's the case, why isn't it done that way at other USAF bases with part-time towers?C

If that's the case, it is a misuse of Class D airspace. Controlled airspace is designated for air traffic control purposes, not security. If they don't want planes flying over the base, they need to go through rule-making process to get a restricted area.

 

[kkoran]

I wonder if ATC has the required communications to the ground when the tower is closed?

 

[Captain]

They do.

Didn't know that. Well, there goes my theory.

 

[ARFlyer]

KXNA TWR & APP/DEP close at 11:00PM. It reverts to an
E with Memphis Center being the controlling agency.

I've had students call Razorback Approach for miles with no reply. Then I'll politely tell them to look at their AF/D.