Expert: Mike Hicks - 9/11/2006

Question
Mike,

I fly near an airport in the San Diego area (Palomar Airport in Carlsbad) which has a class E surface area extension (to the ground).  One extension to the east, one to the northwest.  If the airport goes IMC, they are under the impression that the extension is now under their control and can deny entry to any aircraft operating in the class E extension even if those aircraft are able to maintain VMC conditions.  I have found nothing definitive in the FARs, only a section of the AIM which reads:

"(2). Extension to a Surface Area - There are Class E airspace areas that serve as extensions to Class B, Class C, Class D, and Class E surface areas designated for an airport. Such airspace provides controlled airspace to contain standard instrument approach procedures without imposing a communications requirement on pilots operating under VFR."

So may aircraft operate in that class E extension, without ATC clearance when the class D airport (Palomar) is IMC?

Thanks much.

Answer
Without having acces to a VFR map of the area here is the best I can do..hope it helps

I found a few more references in the AIM, but this is basically one of those Examiner type "gotcha" questions that really has no application. Far as I know, E airspace either begins or ends at 700 or 1200 AGL up to 14500. Below 10000 MSL the basic 3 miles visibility and 500 below, 1000 above and 2000 Horizonally is required. If you want to fly under an approach with less than that then good luck to you. On the other hand, if the class E extensions go to the surface, then they are probably part of the Class D to begin with. All class D is "as depicted".

My best advice is if you need to fly over, under, around or near a controlled airport, make a radio call. Then you become "one of the boys" and they won't let you fly into each other.

I copied and pasted some of the AIM paragraphs for you to look at. I'm not familiar with the airport in question, but I suspect that the first one below applies. At any rate, If ATC thinks that it is theirs then you probably need to file IFR or SVFR to get in or out. Whether they are right or wrong, they can still violate you and it's on your dime to fight it. AND, they will probably ask you to surrender your license while you fight it.

d. Arrival extensions for instrument approach procedures may be Class D or Class E airspace. As a general rule, if all extensions are 2 miles or less, they remain part of the Class D surface area. However, if any one extension is greater than 2 miles, then all extensions become Class E.

e. Types of Class E Airspace:

1. Surface area designated for an airport. When designated as a surface area for an airport, the airspace will be configured to contain all instrument procedures.

2. Extension to a surface area. There are Class E airspace areas that serve as extensions to Class B, Class C, and Class D surface areas designated for an airport. Such airspace provides controlled airspace to contain standard instrument approach procedures without imposing a communications requirement on pilots operating under VFR.

3. Airspace used for transition. There are Class E airspace areas beginning at either 700 or 1,200 feet AGL used to transition to/from the terminal or en route environment.

3-2-5. Class D Airspace

a. Definition. Generally, that airspace from the surface to 2,500 feet above the airport elevation (charted in MSL) surrounding those airports that have an operational control tower. The configuration of each Class D airspace area is individually tailored and when instrument procedures are published, the airspace will normally be designed to contain the procedures.