qxeguy
Posts: 81
Joined: Wed Nov 26, 2003 5:53 am

Why Does Ksea Have Class D Airspace

Thu Jun 16, 2005 11:13 am

They are also (for those that don't know) the primary airport surrounded by Bravo airspace. Why do they have both?

Some possibilities..
History..it had D (or the D equivalent) long ago, pre bravo, and they just kinda kept it. But why?

Proximity..very close to 2 other converging class D airports (BFI and RNT). But wouldn't the B still take care of that?

Because it has a tower..and as a general rule, if you have a tower, you have D. I have been too lazy to get my other sectionals to see if other major airports in B airspace also have D, but I don't remember seeing any. I am sure there are others.

Any help in answering this would be wonderful. It has been bugging me for years.

[Edited 2005-06-16 04:15:36]
I fly boxes. Boxes don't bitch. Boxes don't barf. Boxes don't get drunk and do a number 2 on the beverage cart.
 
Pilawt
Posts: 104
Joined: Mon Dec 22, 2003 3:48 pm

RE: Why Does Ksea Have Class D Airspace

Fri Jun 17, 2005 4:35 am

You can't have Class B and D existing simultaneously in the same airspace, but a Class D may (and often does) exist below the floor of Class B.

Class B airspace extends from the surface to 10,000' at KSEA. The Class B floor rises incrementally to the outer edge of the area, in an irregular circular shape up to 30 NM from SEA VORTAC, but the top is 10,000' over the whole area. Class D does not exist at KSEA itself. Class D airspace exists to 5-NM radii around KBFI and KRNT from the surface to the floor of KSEA's Class B or to 2,500' MSL, whichever is lower. The Class D airspaces around KPAE, KTIW, KTCM and KGRF also underlie the KSEA Class B, but the tops of those areas do not extend high enough to reach the Class B floor.

If all the satellite airports were included in Class B airspace, it would be an ATC nightmare, as each aircraft would require Class B clearance and separation. VFR operations at the satellite airports would be much more difficult.

Class D can also exist under the floor of Class C, such as at Pearson Field in Vancouver, WA (KVUO), where Class D exists below the floor of the Class C area of KPDX. KVUO, by the way, is an example of Class D at an airport where there is no tower at all. (KVUO is also the nation's oldest active airport, and will celebrate the centennial of its first aircraft operation on 24 September 2005.)
 
HaveBlue
Posts: 2110
Joined: Fri Jan 30, 2004 3:01 pm

RE: Why Does Ksea Have Class D Airspace

Fri Jun 17, 2005 1:25 pm

We have 2 very recent additions here at DAB. The OMN airport within the last year and a half and EVB within the last few months both became Class D airports below the umbrella of DAB's Class C.
Here Here for Severe Clear!
 
qxeguy
Posts: 81
Joined: Wed Nov 26, 2003 5:53 am

RE: Why Does Ksea Have Class D Airspace

Fri Jun 17, 2005 1:33 pm

Thank you for your response, but it didn't answer my question at all (incidently Seattle Tower and Boeing Tower don't know either..it is called "the great mystery" by both)

Check the Seattle Sectional..better yet the Seattle Terminal Chart...SEA, BFI and RNT have converging Class D. It is depicted by a dashed blue line. I fly out of BFI, and I can tell you that although the surface area of Seattles Bravo is clearly Bravo, SEA certainly does have an outer ring of Delta. I am wondering why D exists there at all.
I fly boxes. Boxes don't bitch. Boxes don't barf. Boxes don't get drunk and do a number 2 on the beverage cart.
 
Ralgha
Posts: 1589
Joined: Tue Nov 09, 1999 6:20 pm

RE: Why Does Ksea Have Class D Airspace

Fri Jun 17, 2005 1:41 pm

It's so you can't bust in real close to the airport without talking to anyone. The inner circle of B at Seatac is less than 4 NM radius, so they fill out the remainder with D.
09 F9 11 02 9D 74 E3 5B D8 41 56 C5 63 56 88 C0
 
OPNLguy
Posts: 11191
Joined: Tue Jun 15, 1999 11:29 am

RE: Why Does Ksea Have Class D Airspace

Fri Jun 17, 2005 2:29 pm

You might try calling SEA ARTCC during M-F biz hours and ask for "airspace and procedures"...
ALL views, opinions expressed are mine ONLY and are NOT representative of those shared by Southwest Airlines Co.
 
Pilawt
Posts: 104
Joined: Mon Dec 22, 2003 3:48 pm

RE: Why Does Ksea Have Class D Airspace

Sat Jun 18, 2005 12:30 am

Whoa, you're right ... I completely missed that outer ring on the chart, and missed the whole point of your question. Sorry.

That's why I usually file IFR when going into BFI; so I don't have to worry about all those sneaky little lines.  blush 
 
HAL
Posts: 1743
Joined: Tue Jan 15, 2002 1:38 am

RE: Why Does Ksea Have Class D Airspace

Wed Jun 22, 2005 3:17 am

If you look at the chart, you can get within a mile of Sea-Tac airport to the northeast and still be outside the class B airspace. They did that because of the concentration of general aviation traffic coming in and out of Boeing field. However since both Sea-Tac and Boeing are 24-hour tower controlled fields, they still have class D airspace around them to the normal distance of about 5 miles to ensure the required visibility, cloud clearance, and communication regulations are met. That class D airspace includes all the area that isn't taken up by the class B airspace. So even though you can fly up the Auburn valley at 1500 feet within 2 miles of Sea-Tac and not enter the class B airspace, by the time you pass the south end of the field you're in class D airspace and had better be talking to one of the towers (Sea-Tac, Boeing, or Renton), and be following the class D visibility and cloud clearance requirements.

HAL
One smooth landing is skill. Two in a row is luck. Three in a row and someone is lying.

Who is online

Users browsing this forum: KarelXWB and 10 guests

Popular Searches On Airliners.net

Top Photos of Last:   24 Hours  •  48 Hours  •  7 Days  •  30 Days  •  180 Days  •  365 Days  •  All Time

Military Aircraft Every type from fighters to helicopters from air forces around the globe

Classic Airliners Props and jets from the good old days

Flight Decks Views from inside the cockpit

Aircraft Cabins Passenger cabin shots showing seat arrangements as well as cargo aircraft interior

Cargo Aircraft Pictures of great freighter aircraft

Government Aircraft Aircraft flying government officials

Helicopters Our large helicopter section. Both military and civil versions

Blimps / Airships Everything from the Goodyear blimp to the Zeppelin

Night Photos Beautiful shots taken while the sun is below the horizon

Accidents Accident, incident and crash related photos

Air to Air Photos taken by airborne photographers of airborne aircraft

Special Paint Schemes Aircraft painted in beautiful and original liveries

Airport Overviews Airport overviews from the air or ground

Tails and Winglets Tail and Winglet closeups with beautiful airline logos