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I'd like to clarify a very specific statement from 14 CFR Part 103:

103.17 OPERATIONS IN CERTAIN AIRSPACE No Person may operate an ultralight vehicle within Class A, Class B, Class C, or Class D airspace or within the lateral boundaries of the surface area of Class E airspace designated for an airport unless that person has prior authorization from the ATC facility having jurisdiction over that airspace.

The specific statement I need help with is:

or within the lateral boundaries of the surface area of Class E airspace designated for an airport

As we know, Class E airspace can start at the surface (shown as a dashed magenta line on sectional charts), start at 700' AGL (shown as a magenta border), start at 1,200' AGL (shown as a blue border), or start at 14,500 MSL.

In the Aeronautical Information Manual (AIM), the following relevant information is given about Class E airspace under section 3-2-6:

e. Functions of Class E Airspace. Class E airspace may be designated for the following purposes:

  1. 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. The airspace will be configured to contain all instrument procedures.

(a) To qualify for a Class E surface area, the airport must have weather observation and reporting capability, and communications capability must exist with aircraft down to the runway surface.

(b) A Class E surface area may also be designated to accommodate part-time operations at a Class C or Class D airspace location (for example, those periods when the control tower is not in operation).

(c) Pilots should refer to the airport page in the applicable Chart Supplement U.S. for surface area status information.

  1. Extension to a surface area. Class E airspace may be designated as extensions to Class B, Class C, Class D, and Class E surface areas. Class E airspace extensions begin at the surface and extend up to the overlying controlled airspace. The extensions provide controlled airspace to contain standard instrument approach procedures without imposing a communications requirement on pilots operating under VFR. Surface area arrival extensions become part of the surface area and are in effect during the same times as the surface area.

Part 103 states "or within the lateral boundaries of the surface area of Class E airspace designated for an airport".

That statement has two parts I need help with:

within the lateral boundaries of

and

the surface area of Class E airspace designated for an airport

When looking at a sectional and reading the relevant section of the AIM, what exactly applies to part 103?

I've seen a few attempts to answer the following questions in other forums and it always ends up in a debate including conflicting info from pilots and even FSDO personnel. Is there a clear, definitive "aviation lawyer" legal type answer to the following questions (I'm not concerned with any "should" type discussions here)?

Question 1:

What exactly is the surface area of Class E airspace designated for an airport? Is it any dashed magenta area on a sectional or is it something more specific or different?

Question 2:

And does the within the lateral boundaries of part mean there is no ceiling (meaning an ultralight can't overfly these areas at any altitude) or something else?

For example (for Q3&4), BLYTHE (BLH) (Phoenix sectional) airport:

enter image description here

Question 3:

Can an ultralight fly within the dashed magenta circle? Is this an example of a "surface area of Class E airspace designated for an airport"?

Question 4:

If this is true, what is the ceiling that affects ultralight aircraft? Is it the 700' AGL Class E airspace above the airport? Or does it go all the way up to FL180? In other words, can an ultralight overfly this airport as long as it flies more than 700' AGL?

And what about (for Q5&6) Yuma (NYL) (Phoenix sectional) airport:

enter image description here

Question 5:

Can an ultralight fly within the two Class E extensions to the Class D airport? Or are these two extensions still considered "surface areas of Class E airspace designated for an airport" (and this has the same answer as question 1 above)?

Question 6:

If an ultralight can't fly within these two Class E extensions, can an ultralight flow over these extensions? Is the ceiling 2,700' MSL (same as the Class D airspace of the airport) or is the ceiling 700' AGL (due to the overlying Class E airspace in the area)? Or does it go to FL180 (which would make no sense since an ultralight can overfly the Class D airspace)?

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  • $\begingroup$ Related $\endgroup$ – Pondlife Feb 6 '17 at 18:51
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    $\begingroup$ @Pondlife I rolled back your title edit because it completely changed the focus of my question. $\endgroup$ – rmaddy Feb 6 '17 at 20:46
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NOTE: This answer was originally given based on a conservative interpretation of available interpretations of the regulations. New guidance may shed new light on the issue. The interpretation presented here may be superseded; see the discussion and other answers.


Short Answer

within the lateral boundaries of the surface area of Class E airspace designated for an airport

This refers to the horizontal dimensions of Class E airspace that contacts the surface of the earth without any reference to vertical dimensions or ceiling.


Long Answer

You ask for definitive and official clarification on the following two portions of §103.17:

within the lateral boundaries of

and

the surface area of Class E airspace designated for an airport

Here is §103.17 in full for context:

Operations in certain airspace.
No person may operate an ultralight vehicle within Class A, Class B, Class C, or Class D airspace or within the lateral boundaries of the surface area of Class E airspace designated for an airport unless that person has prior authorization from the ATC facility having jurisdiction over that airspace.

I will address these two clauses separately based on the official legal interpretations, then address your six case questions based on the definitions established. Throughout this answer I will also assume that no "prior authorization" has been obtained from ATC that would give exception to the above regulation.


"within the lateral boundaries of..."

The terminology, "the lateral boundaries" refers to the horizontal limits of an area in question; the terminology does not refer to any vertical limits.

Because "lateral" defines only horizontal area—not vertical—the terminology "within the lateral boundaries" means within the horizontal area defined, without respect to any vertical bounds, unless otherwise specified.

Where a regulation needs to define vertical limits, additional terminology is used, such as "below [altitude]" or "above the ceiling". Where the totality of an airspace is intended, a comprehensive phraseology is used, such as "within the lateral and vertical boundaries".

Compare the ultralight rule of §103.17 with wording of the following regulations respectively governing unmanned free balloons and transponder use—both of which define the horizontal limits of the airspace in question by the same terminology "within the lateral boundaries of":

§101.33 (a) Unless otherwise authorized by ATC, below 2,000 feet above the surface within the lateral boundaries of the surface areas of Class B, Class C, Class D, or Class E airspace designated for an airport;

§91.215 (4) All aircraft in all airspace above the ceiling and within the lateral boundaries of a Class B or Class C airspace area designated for an airport upward to 10,000 feet MSL; and


"...the surface area of Class E airspace..."

Note: Credit goes to Pondlife for identifying the legal interpretation—Hucker (2006)—that addresses this issue.

The FAA has defined this terminology very clearly and without ambiguity.

The following definition of "surface area" is provided in the Pilot Controller Glossary:

SURFACE AREA− The airspace contained by the lateral boundary of the Class B, C, D, or E airspace designated for an airport that begins at the surface and extends upward.

Tthe FAA has issued a letter of legal interpretation—Hucker (2006)—that definitively addresses this:

The term “surface areas” refers only to those components of airspace that come in contact with the surface of the earth.

Moreover, Hucker (2006) addresses the regulations of §91.303 pertaining to aerobatic flight (which contains some of the same language as §103.17):

§91.303 (c) Within the lateral boundaries of the surface areas of Class B, Class C, Class D, or Class E airspace designated for an airport;

In addressing this regulation, Hucker (2006) makes clear that the above defines lateral areas without any vertical limitation.


"...designated for an airport"

I would argue that this phraseology is superfluous and that the FAA also regards it as such. I know of no Class B, C, D, or Class E airspace that extends to the surface that is not designated for an airport. I would be happy to be shown wrong, however.

As I said, I believe the FAA also views this language as superfluous:

In the FAA's ATC order JO 7110.65W the rules for SVFR are addressed in reference to the applicable airspaces, but without differentiation as to whether or not such airspaces are designated for an airport:

7-5-1 2. Only within the lateral boundaries of Class B, Class C, Class D, or Class E surface areas, below 10,000 feet MSL.

Additionally, in a memorandum of legal interpretation, Duncan (2015), the airspeed rules of §91.117 for Class B airspace are addressed, also without differentiation as to whether or not the Class B airspace is designated for an airport.


Given the above, I would answer your six questions as follows:

Question 1:

What exactly is the surface area of Class E airspace designated for an airport? Is it any dashed magenta area on a sectional or is it something more specific or different?

Yes, the surface area of Class E airspace is the component of Class E airspace that contacts the surface of the earth and extends upward.

Question 2:

And does the within the lateral boundaries of part mean there is no ceiling (meaning an ultralight can't overfly these areas at any altitude) or something else?

Yes, in the context of §103.17 where no vertical dimensions are specified, within the lateral boundaries means inside the horizontal area with no vertical limitation or ceiling.

Question 3:

Can an ultralight fly within the dashed magenta circle? Is this an example of a "surface area of Class E airspace designated for an airport"?

No, without prior authorization, no person may operate an ultralight vehicle within the lateral boundaries of the surface area of Class E airspace designated for an airport. Yes, this is an example of Class E airspace designated for an airport.

Question 4:

If this is true, what is the ceiling that affects ultralight aircraft? Is it the 700' AGL Class E airspace above the airport? Or does it go all the way up to FL180? In other words, can an ultralight overfly this airport as long as it flies more than 700' AGL?

Since §103.17 does not define any vertical limitation, no person may operate an ultralight vehicle anywhere within the lateral boundaries of the surface area of Class E airspace designated for an airport. This prohibition, includes any airspace vertically overlying the Class E surface area, including the Class A airspace at and above FL180.

Question 5:

Can an ultralight fly within the two Class E extensions to the Class D airport? Or are these two extensions still considered "surface areas of Class E airspace designated for an airport" (and this has the same answer as question 1 above)?

No, these areas are surface areas of Class E airspace designated for an airport.

Question 6:

If an ultralight can't fly within these two Class E extensions, can an ultralight flow over these extensions? Is the ceiling 2,700' MSL (same as the Class D airspace of the airport) or is the ceiling 700' AGL (due to the overlying Class E airspace in the area)? Or does it go to FL180 (which would make no sense since an ultralight can overfly the Class D airspace)?

No, an ultralight must not be flown over these extensions.

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  • $\begingroup$ Thank you. This answer agrees with my own understanding. But I was hoping I was wrong. Every other use of "lateral boundary" that I saw in other regs made mention of altitudes just as in your examples. And since 103.17 doesn't, it appears to indicate a needless restriction for ultralights. Why can I fly over a class D airspace but not over an associated class E surface extension to that class D airspace, for example? $\endgroup$ – rmaddy Feb 7 '17 at 20:56
  • $\begingroup$ @rmaddy I agree that the regulation seems unnecessarily restrictive when it comes to class E airspace. However, neither do I think that it would make sense to prohibit ultralight flight from the surface to 700 AGL, but allow flight in that same lateral area above 700 AGL, which alternate interpretations would suggest. $\endgroup$ – J Walters Feb 7 '17 at 21:04
  • $\begingroup$ Dug into this more, I'm not sure any more whether I agree with the "lateral boundary" part of this answer. Here's why. Sections 91.215(b)(5)(ii), 91.255(d)(3), 101.33(a), and 135.205(b) all use the phrase "the lateral boundaries of" as well as clear altitude delineations. Those are clear. Then there is section 91.303 (aerobatics) which uses the same term. But the only altitude reference is staying above 1500' AGL. We know this means you are allowed to do aerobatics under the outer rings of class B above 1500' AGL. But can you do aerobatics over an airport, above its airspace? Continued... $\endgroup$ – rmaddy Feb 9 '17 at 17:03
  • $\begingroup$ And of course section 103.17 with no specific altitude references. So now I can't decide whether a lack of complete altitude references along with "the lateral boundaries of" means surface to outer space or it only means within the altitude range containing the referenced airspace. $\endgroup$ – rmaddy Feb 9 '17 at 17:04
  • $\begingroup$ @rmaddy §91.303(c) states "within the lateral boundaries of the surface areas of Class B". If this meant only that portion of the surface area airspace that underlies any above airspace, it would be mostly redundant since §91.303(e) already prohibits aerobatics below 1500 AGL. $\endgroup$ – J Walters Feb 9 '17 at 17:47
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The definitive source for what airspace is where for airports is contained in an FAA Order. That order is updated periodically, and has numerous amendments between issuances. The current order is JO 7400.11B. The order is exhaustive and states on page A-1 that any airspace not defined within is by default Class G.

I submit that your answer is more precisely defined by the above referenced order, and not specifically by a sectional, as the sectional is a derived document from the order.

Using the OP example of Yuma, Appendix E of the order says:

AWP AZ E2 Yuma, AZ Yuma MCAS-Yuma International Airport, AZ (lat. 32°39'24''N., long. 114°36'22''W.) Somerton, Somerton Airport, AZ (lat. 32°36'03''N., long. 114°39'57''W.) That airspace, within a 5.2-mile radius of Yuma MCAS/Yuma International Airport, excluding that airspace from the surface up to and including 300 feet above the surface from lat. 32°36'52'' N., long. 114°41'44'' W.; thence east to lat. 32°36'52'' N., long. 114°39'30'' W.; thence south to lat. 32°34'55'' N., long. 114°39'30'' W.; thence clockwise along the 5.2-mile radius to the point of beginning. The Class E 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.

Since the effective date and time are published in the AFD, you would refer to that publication, and also any subsequent NOTAMs. BUT since that description has an exclusion up to 300 feet, you would exclude that area, as Class E does not begin at the surface at those exclusion areas.

A couple of things to keep in mind:

  1. You can overfly with ATC approval.
  2. Class E extends to overlying controlled airspace. I guess that could be Class (A outside continental area?), B, C or Class E beginning at 700 or 1200. It is most often Class E beginning at 700 feet AGL.
  3. When Class E extends to the surface, it is ALWAYS associated with an airport, and there are a list of conditions which apply (WX reporting, com, etc.)
  4. The Class E description is always in the order or addendums.
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  • $\begingroup$ After statement "Using the OP example of Yuma, Appendix E of the order says:", you need to explain that description that follows lies within a section of JO 7400 that is titled as follows: "Class E Airspace Areas Designated as an Extension to a Class D or Class E". Unlike the section that describes the OTHER kind of Class-E-to-surface airspace, that section does NOT bear the title "Class E Airspace Areas Designated as a Surface Area", nor is the title of that section followed by the descriptive sentence "The Class E airspace areas listed below are designated as a surface area for an airport"" $\endgroup$ – quiet flyer Oct 11 '18 at 22:50
  • $\begingroup$ Including those details would make your reference to JO 7400 much more meaningful-- but it also might force a substantial rewriting of your answer and even a change in your ultimate conclusions. This statement in particular would need to be deleted-- "When Class E extends to the surface, it is ALWAYS associated with an airport" $\endgroup$ – quiet flyer Oct 11 '18 at 22:51
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A special dispensation for ultralight pilots:

Clip and save:

“My navigation of the national airspace system is informed by the Final Rule published by the FAA in the October 5 1993 edition of the Federal Register (volume 58). The section entitled “Background”, on the third column of page 51966, states that the language of FAR 91.157(a) as it existed immediately prior to that time, which included the phrase “Within the lateral boundaries of the surface areas of … Class E airspace designated for an airport”, would not include any Class E airspace located above the floor of any 700’ or 1200’ AGL E5 transition area that was defined to overly the surface-level Class E airspace. Thus the FAA felt there was a need to modify the phraseology of FAR 91.157(a) to include more airspace. The language was changed to read “within the airspace contained by the upward extension of the lateral boundaries of the controlled airspace designated to the surface for an airport". I note that FAR 103.17 was never similarly modified and still contains phraseology identical to the earlier phraseology of FAR 91.157(a), and thus according to the logic of the October 5 1993 Final Rule, FAR 103.17 does not require prior authorization for ultralight flight in any surface-level Class E airspace (E2, E3, E4 airspace), so long as said flight is conducted above the base of a 700’ or 1200’ AGL E5 transition area that is defined to also cover the area covered by said surface-level Class E airspace.”

Clip above this line ............................................................................

This is completely absurd, of course, but who are we to argue with the FAA?

Consider for example FAR 91.303(c) prohibiting aerobatic flight "within the lateral boundaries of the surface areas of... Class E airspace designated for an airport"-- does this also not apply above 700' in most surface-level Class E airspace? And likewise FAR 101.33(a), the prohibition on operating unmanned free balloons below 2000' AGL "within the lateral boundaries of the surface areas of... Class E airspace designated for an airport" -- does this also not apply above 700' in most surface-level Class E airspace?

For a saner view, see this answer.

A piece of trivia-- during the rule-making process leading up to the 1993 "alphabet" airspace re-designation, at one point the plan was that when the airspace formerly known as "control zones" (which in most cases extended up to the base of the Continental Control Area at 14,500' MSL) where converted into surface-level Class E (and higher) controlled airspace, the surface-level Class E airspaces would have specific defined ceilings comparable to what was planned for the Class D airspaces. But, that was never implemented-- the plans changed before the Final Rule was issued.

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  • $\begingroup$ This relates to questions 2, 4, and 6. $\endgroup$ – quiet flyer May 6 at 13:02
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Related--

(Q) What indication has the FAA given that phrases like "surface area of Class E airspace designated for an airport" do or don't include E4 "extensions"? ,

(A) What indication has the FAA given that phrases like “surface area of Class E airspace designated for an airport” do or don't include E4 “extensions”?,

and

(A) In the US, how does the distinction between E2 and E3/E4 airspace affect pilots?

In short, the situation is ambiguous as to whether ultralights may fly in the "extensions" without "prior authorization".

What is not ambiguous, however, is that if we answer "no", then we must recognize that the airspace we are talking about extends upwards indefinitely, due to the "within the lateral boundaries of" language used in the regulation. The same is true of E2 "surface area" airspace (example KONP), which is not an "extension" and which is unambiguously within the scope of the airspace addressed by the regulation (103.17) and therefore off-limits (without prior authorization) for ultralight flight.

The idea that the off-limits airspace somehow has a cap at 700' AGL or 1200' AGL, or in the case of an "extension", at the ceiling of the adjoined Class D airspace, is not supportable at all.

The truth is that the FAA is deeply divided as to whether phrases in the FARs like "surface area", "designated for an airport", and "surface area of controlled airspace designated for an airport" should or should not be construed to include surface-level Class E "extensions".1 Ambiguity around this issue has existed ever since the 1993 "alphabet" airspace re-designation.2 There's some consideration of a future rule-making effort to address this issue.3 It's possible that the language in AIM 3-2-6, as well as in the legend of the Chart Supplements, that reads "Surface area arrival extensions become part of the surface area and are in effect during the same times as the surface area" will be changed in the future to avoid implying that all regulations that apply to the core "surface area" should automatically be construed to apply to the surface-level Class E "extensions" as well.4

Footnotes:

1,2,3,4) Source-- comments made by high-level FAA staffers during April 2021 airspace charting meeting.

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18-1-2. CLASS E SURFACE AREAS

Class E Surface area extend upward from the surface to a designated altitude; or to the adjacent or overlaying controlled airspace


103.17 No person may operate an ultralight vehicle within Class A, Class B, Class C, or Class D airspace or within the lateral boundaries of the surface area of Class E airspace designated for an airport

*** The within the lateral boundaries = this means the area inside the dashed magenta. The dashed magenta line does not exist past certain altitudes. = to a designated altitude; or to the adjacent or overlaying

Example- If referring to a non towered airport, the dashed magenta line (lateral boundary) stops at 700' agl. (Its all Class E, it's now Class E 700' boundary. This means there is no longer a surface area boundary past that altitude)

You can fly over the dashed magenta above 700' agl because thats the "designated altitude" and its no longer a "surface area". It is now Class E 700, then that lateral boundary stop at Class E 1200.

Below 700' agl you would be crossing the dashed magenta (lateral boundaries) that exists below 700' and operating within.

Cant remember where I got this from, helps explain rather well.

Class E Airspace: Controlled airspace is officially defined by exclusion, which often does not tell you much. By that reasoning, Class E airspace is controlled airspace that is not Class A, B, C or D or G (explained below) airspace. Not too helpful, but you can be sure that there is a lot of Class E airspace, so much that one could think of it as "E" for Elemental or Everywhere airspace, the airspace out of which all other types are carved. It is the filler that fills in under Class A, ie; below 18,000' msl, and between Classes B,C and D and over the top of Class G (described below). Its volume is vast. If we ignore the upper cover of Class A airspace, it is safe to say that there is a lot more E than all the other kinds combined. Ultralights fly freely in most of Class E space with one exception described below.

Class E almost always has one of four lower limits: those being surface, 700' AGL, 1200' AGL, or 14,500' MSL (discussed below). Most of the country has a Class E lower limit of 1200' AGL. Where it drops to 700' AGL it is shown by a broad magenta line with a fuzzy side. The fuzzy side is the side where the floor of Class E is 700' AGL. The floor may also drop to the surface where it is called "Class E Surface Area". A dashed magenta line indicates the boundary of the Class E Surface Area. So on the image, you can see the dashed magenta line around the airport indicating the outer boundary of the Class E Surface

enter image description here

Class E Surface Areas and Floors

Area and outside of that a meandering wide magenta line showing where the floor of Class E goes from 700' agl to 1200' agl as you go away from the airport.

The major exception to ultralights being allowed in Class E Airspace is: FAR, Part 103.17 -- "No person may operate an ultralight vehicle within [snip] the lateral boundaries of the surface area of Class E airspace designated for an airport unless that person has prior authorization from the ATC facility having jurisdiction over that airspace."

"Class E Surface Area," looks much like Class D but only in dashed magenta, not dashed blue. Notice there is no upper altitude number within a box like there was in Class D. The question then becomes... what is the upper limit? How is this airspace boundary defined?

The FAA has a definition for "Class E Surface Area" that includes an upper limit. It is the height of the surrounding Class E floor just outside the lateral boundaries of the Class E Surface Area. For example in the image (above), the upper limit of Class E Surface Area is 700' agl meaning you could fly your ultralight vehicle over this airport but you must remain at least 700' agl as you fly over. fly over.

enter image description here

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  • $\begingroup$ In all my time flying through Class E airspace that extends to the surface, I have never encountered a dashed magenta line. My understanding is that these exist on the two-dimensional sectional chart only, and do not have any vertical dimension. $\endgroup$ – J Walters Feb 7 '17 at 19:54
  • $\begingroup$ @JWalters they are depicted as a two dimensional area on the chart, but they have height, and when associated with an airport, which is the only instance that Class E begins at the surface, they have a volume by virtue of their extension upward to the underlying controlled airspace. Most of the time that airspace is Class E, beginning at 700 feet AGL. $\endgroup$ – mongo Oct 24 '17 at 18:40
  • $\begingroup$ Hi Mike. We've gone round and round about this on another forum. This is just not accurate at all. Specifically the statement "The FAA has a definition for "Class E Surface Area" that includes an upper limit. It is the height of the surrounding Class E floor just outside the lateral boundaries of the Class E Surface Area." Admittedly the some of the FAA definitions are written in rather obtuse language-- hence my very long answer exploring that language--- but your interpretation is not correct. I recognized your argument long before I noticed the name at the end and it just won't fly. $\endgroup$ – quiet flyer Oct 12 '18 at 9:09
  • $\begingroup$ As someone else said in another comment on another related forum aviation.stackexchange.com/questions/35407/…, "within the lateral boundaries of" has no implied altitude restriction. That term, in English, implies surface to outer space". Or are we to believe that they were only banning aerobatics below 700' AGL, as far as the Class-E-to-surface is concerned? Something to think about-- $\endgroup$ – quiet flyer Oct 12 '18 at 9:11
  • $\begingroup$ Noting that "within the lateral boundaries of the surface area of Class E arpce dsgntd for an airport" appears in both FAR 103.17 and FAR 107.41 (pertains to Small Unmanned Aircraft), one could use one of the on-line forums for commercial drone operators a sounding board for ideas like "we're fine to overfly Class-E-to-surface surrounding an airport at 701'", or "the dashed magenta lines not in effect if the wx is above standard Class E minimums". Read more: forum.hanggliding.org/… Unmanned Aircraft $\endgroup$ – quiet flyer Oct 12 '18 at 15:14

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