Wonder Boy wrote: ↑
Wed Oct 10, 2018 2:04 pm
Ask yourself this, if the intent if for us not to fly over at any altitude, it would be phrased that way.
It would be so clear to say "can not fly over the surface area" if that was the intent.
But they say "within
the lateral boundaries" and to give the surface area definition "extends up to a designated altitude".
Mike, everything I have to say about parsing the meaning of the regs is given here -- https://aviation.stackexchange.com/ques ... thout-prio
. Go down far enough and you will get to a section that addresses the altitude limits. Also see https://aviation.stackexchange.com/ques ... 5806#55806
But, since this discussion seems to be still on going I guess I'll take one more stab at saying a little more-- trying to specifically address what you said above--
I think that the reason they use the "within the lateral boundaries" phrase is that they've gone and NAMED or DESIGNATED the airspace as a "Surface Area" and so it no longer remains clear that if you were to say "within the surface area" or perhaps "over the surface area" you would mean anywhere over the surface footprint. If we were to say "within the Surface Area" or "over the Surface Area" and we're talking about a chunk of airspace named a "Surface Area" rather than the surface footprint of something, then we might want to know if there is a vertical limit to that chunk of airspace and where it is -- is there a certain height at which we are no longer "within the Surface Area" because we've climbed above the "Surface Area"? The clearest way they could think of to deal with this was just to say "within the lateral boundaries of the airspace designated as a surface area", meaning anywhere within the vertical wall rising upward from the dashed magenta line--the ground footprint of the "Surface Area"-- all the way to outer space. To understand why that language makes any sense at all you have understand that they've gone and NAMED or DESIGNATED the actual airspace as a "Surface Area", so the phrase no longer works well as a description just of the footprint on the ground of that airspace.
By the way, in the part of FAA Order JO 7400 where they say "Surface area designated for an airport where a control tower is not in operation. Class E surface areas extend upward from the surface to a designated altitude, or to the adjacent or overlying controlled airspace.", I've not come across one single case in all the airspace descriptions that follow that heading where they actually do designate any particular altitude. Maybe there is one but I haven't found it. So you just fall back on the standard definition of Class E as having no upper limit unless it is runs in to some higher class.
And by the way, yes I think you might indeed be able to make the case that a Class-E-to-surface area "designated for an airport", i.e. surrounding the airport whose approaches it protects, DOES in some sense come to an end if it hits an overlying Class C shelf. But even above the Class C shelf -- or even within the Class C shelf for that matter you are still technically "within the lateral boundaries" of "the airspace designated as a surface area for an airport". Could you technically make the case that above the ceiling of the Class C shelf you are in G rather than E? You probably could, IF it weren't for the fact that the definitions of ANOTHER other chunk of Class E airspace-- specifically the surrounding chunk whose floor ends at 700' AGL-- probably is written to include all the airspace within the faded magenta boundary except that taken up by the Class C, etc. So you are in that chunk of Class E when you are above the Class C shelf. Or take the simple case of Class-E-to-surface airspace designated for an airport like at Newport Oregon-- http://vfrmap.com/?type=vfrc&lat=44.580 ... 58&zoom=10
-- I may be wrong but I bet that JO 7400 doesn't even address whether, if you are in an airplane above Newport at 800' AGL, you are within the Class-E-to-airspace "designated as a surface area for the airport", or within the Class E w/ 700' floor designated by the faded magenta border. I bet an aircraft at that point in space (800' AGL) would fit the technical definitions of BOTH of these types of airspaces as delineated in JO 7400. So it would be in BOTH kinds of Class E at once. In fact if it were at 1300' it would fit within three different boundaries given for Class E airspace -- the Class-E-to-surface, the Class E starting at 700', and the Class E starting at 1200'. I just looked at page E-652 (covers Class-E-not-to-surface boundaries near Newport) in JO 7400 https://www.faa.gov/documentLibrary/med ... 00.11C.pdf
and that's sure what it looks like to me. That's why we don't need to worry about what happens above the top of the Class C shelf-- we're still in some other Class E. And we're still within the "lateral boundaries of the Class E Airspace Designated As a Surface Area For An Airport", even if we aren't actually in the "Class E Airspace Designated As a Surface Area For An Airport." And there's nothing in the regs that gives any significance to the fact that as we climbed through the Class C shelf (with permission of course) we may have technically left the "Airspace Designated As a Surface Area For An Airport." Because as we come out of the top of the Class C shelf, we still end up back in Class E airspace, and we still are "within the lateral boundaries" of the lower chunk of Class E, the chunk that was "Designated As a Surface Area For An Airport."
Don't take the quotes in this post as verbatim from the regs, I'm just trying to convey the general meaning. See the link I gave at the front of this post for verbatim quotes
Man this can gobble up time. Well, anyone who does go talk the FAA, let us know whatever you find-- and who (or at least in what capacity the person was) you heard it from. If anyone comes across links to official past rulings on this stuff other than the one I've mentioned (Jan 10 2018 Memorandum), though honestly I'm afraid those past rulings may say things I'd rather not hear. (re the extensions.)
Re the altitude limits, if you want to ask a question, try to phrase it carefully. In regard to the altitude limit, we're less interested to know where is the top of the airspace variously called (in the FAR's , JO 7400, AIM, etc ) "surface area of Class E airspace designated for an airport", "Class E Airspace Areas Designated as a Surface Area", " Class E airspace areas..designated as a surface area for an airport", "Surface area designated for an airport where a control tower is not in operation", or "Class E surface area". (By the way these all refer to the exact same thing-- the kind of Class-E-to-surface airspace that actually surrounds the airport whose approaches it protects.) Rather than worrying about where is the top of the airspace defined by these phrases, what we really need to know is what is the vertical limit of the airspace defined by the exact phrase "within the lateral boundaries of the surface area of Class E airspace designated for an airport". Don't confuse them by asking about the other stuff. (And by the way everything in this paragraph IS an exact quote from FAR 103.17, JO 7400, or the AIM.)