Airspace Question

cleared4theoption

cleared4theoption

Pre-takeoff checklist
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Jeremy
I've been practicing my airspace knowledge by looking at TACs and sectionals. I came accross an oddity, and wondered what to make of it.

If you look at the Kansas City TAC (I was looking on skyvector) the Class D for KMKC has a ceiling of 3300. MOST of that airspace lies under the Class B shelf for KMCI that has a floor of 4000...that's easy enough, it has 700 feet of Class E in between...
But in the Northwest corner of the D airspace, the B shelf comes down to 3000 feet, and in one small sliver it is at 2400...
Does the class B override the class D? Is it the other way around?:dunno:
 
Very good question. I've never seen something like that before. The answer to this question (like most) is found in the AIM:

AIM 3-1-3

3-1-3. Hierarchy of Overlapping Airspace Designations ​
a. When overlapping airspace designations apply to the same airspace, the operating rules associated with the more restrictive airspace designation apply.
Click to expand...

And the next paragraph:

b. For the purpose of clarification:
1. Class A airspace is more restrictive than Class B, Class C, Class D, Class E, or Class G airspace;
2. Class B airspace is more restrictive than Class C, Class D, Class E, or Class G airspace;
3. Class C airspace is more restrictive than Class D, Class E, or Class G airspace;
4. Class D airspace is more restrictive than Class E or Class G airspace; and
5. Class E is more restrictive than Class G airspace.
Click to expand...
So, the Class B airspace rules would apply.
 
good find..thats for sure an ambiguous depiction . I would guess that the B overrides the D from 2400 up.
 
What PJ wrote is generally true. However, in some cases, when it's a B/D overlap like this, and the tower is part-time, there's an LoA in effect which cedes control of the overlap space to Tower, but it reverts to TRACON control when the Tower is closed. Look for notes about that in the A/FD or on the chart. Either way, if tower sends you into the overlap, ask.
 
cleared4theoption said:
I've been practicing my airspace knowledge by looking at TACs and sectionals. I came accross an oddity, and wondered what to make of it.

If you look at the Kansas City TAC (I was looking on skyvector) the Class D for KMKC has a ceiling of 3300. MOST of that airspace lies under the Class B shelf for KMCI that has a floor of 4000...that's easy enough, it has 700 feet of Class E in between...
But in the Northwest corner of the D airspace, the B shelf comes down to 3000 feet, and in one small sliver it is at 2400...
Does the class B override the class D? Is it the other way around?:dunno:
Click to expand...

It's neither. They don't overlap, the Class D surface area is excluded from the Class B airspace. Here's the Class D Airspace Legal Description:

ACE MO D Kansas City Charles B. Wheeler Downtown Airport, MO​
Kansas City Charles B. Wheeler Downtown Airport, MO
(lat. 39º07'24''N., long. 94º35'34''W.)

That airspace extending upward from the surface to and including 3,300 feet MSL within a
4.2-mile radius of Kansas City Charles B. Wheeler Downtown Airport; excluding that airspace​
within the Kansas City, MO Class B airspace area.
 
Ron Levy said:
What PJ wrote is generally true. However, in some cases, when it's a B/D overlap like this, and the tower is part-time, there's an LoA in effect which cedes control of the overlap space to Tower, but it reverts to TRACON control when the Tower is closed. Look for notes about that in the A/FD or on the chart. Either way, if tower sends you into the overlap, ask.
Click to expand...

What are some of those cases?
 
roncachamp said:
....the Class D surface area is excluded from the Class B airspace.
Click to expand...

Other way 'round. The Class B airspace is excluded from the Class D. Meaning the Class B is intact & the Class D only exists outside the B.
 
Joe B said:
Other way 'round. The Class B airspace is excluded from the Class D. Meaning the Class B is intact & the Class D only exists outside the B.
Click to expand...

If the Class B airspace was excluded from the Class D airspace it would mean Class B is giving way to Class D.
 
The way I read that chart, inside that sliver is Class B from 8,000 to 2,400 and is Class D from 2.400 to the surface.
 
Ron Levy said:
Martin State Airport (KMTN).
Click to expand...

There's no overlap there either, the Class B airspace is excluded from the MTN Class D airspace.


AEA MD D Baltimore, Martin State Airport, MD
Martin State Airport, Baltimore, MD
(lat. 39°19'32"N., long. 76°24'50"W.)
Baltimore VORTAC
(lat. 39°10'15"N., long. 76°39'41"W.)
Martin NDB​
(lat. 39°17'59"N., long. 76°22'49"W.)

That airspace extending upward from the surface to and including 2,500 feet MSL within a
4.3-mile radius of the Martin State Airport and within 4.4 miles each side of a 14.7-mile radius
arc of the Baltimore VORTAC extending clockwise from the Baltimore VORTAC 030° radial to
the VORTAC 046° radial, excluding that airspace within the Washington Tri-Area Class B
airspace area and Restricted Areas R-4001A and R-4001B when they are in effect. This Class D
airspace area is effective during the specific dates and times established in advance by a Notice
to Airmen. The effective date and time will thereafter be continuously published in the
Airport/Facility Directory.​


AMENDMENTS 12/8/94 59 FR 46750 (Revised)
 
roncachamp said:
There's no overlap there either, the Class B airspace is excluded from the MTN Class D airspace.


AEA MD D Baltimore, Martin State Airport, MD
Martin State Airport, Baltimore, MD
(lat. 39°19'32"N., long. 76°24'50"W.)
Baltimore VORTAC
(lat. 39°10'15"N., long. 76°39'41"W.)
Martin NDB​
(lat. 39°17'59"N., long. 76°22'49"W.)

That airspace extending upward from the surface to and including 2,500 feet MSL within a
4.3-mile radius of the Martin State Airport and within 4.4 miles each side of a 14.7-mile radius
arc of the Baltimore VORTAC extending clockwise from the Baltimore VORTAC 030° radial to
the VORTAC 046° radial, excluding that airspace within the Washington Tri-Area Class B
airspace area and Restricted Areas R-4001A and R-4001B when they are in effect. This Class D
airspace area is effective during the specific dates and times established in advance by a Notice
to Airmen. The effective date and time will thereafter be continuously published in the
Airport/Facility Directory.​


AMENDMENTS 12/8/94 59 FR 46750 (Revised)
Click to expand...
Last time I asked (because they were working me in that area), Martin Tower seemed to think they had an LoA giving them control over that segment when they're in operation.
 
Ron Levy said:
Last time I asked (because they were working me in that area), Martin Tower seemed to think they had an LoA giving them control over that segment when they're in operation.
Click to expand...

This is all the Potomac TRACON and Martin Tower Letter of Agreement has to say about airspace:

"PCT delegates to MTN control responsibility for those aircraft operating within the confines of MTN Class D airspace, except for those portions of MTN Class D airspace that are part of the Washington Tri-Area Class B airspace. PCT shall not approve flights below 2,500 feet where the base of Class B airspace is 2,500 feet, or below 2,000 feet where the base of Class B airspace is 1,500 feet."
 
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