Part 103 vs. The lateral boundaries of the surface area of Class E airspace

[Capt. Geoffrey Thorpe]

Ok, you can't operate a part 103 vehicle "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." 103.17

The AIM says:
"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."

The AIM wording would lead me to believe that the airspace referred to in 103.17 is limited to the "magenta dashed line circle plus sometimes a big dashed rectangle" and not the "magenta fade line around an airport" airspace. Am I right, or is it more insidious than that?

 

[EdFred]

That is how I interpret it.

 

[Capt. Geoffrey Thorpe]

I think I just found the answer to my own question. Order JO-7400.9y has an enumerated list of "Class E Airspace Areas Designated As A Surface Area" which appears to line up with dashed magenta lines or is a part time class D.

 

[BarryCooper]

yes dashed lines

 

[MAKG1]

I agree.

The "magenta faded line around an airport" is the 700 AGL Class E (i.e., the IFR transition area), not the surface area.

FWIW, Class E surface areas don't contain all instrument procedures, despite what the AIM says. None of the approaches for South Lake Tahoe (KTVL) are contained, even if you consider that to apply only once they have entered. For the VOR approach, for instance, the feeders cross the surface area, the IAF is on the boundary, and the procedure turn is outside.

 

[ChemGuy]

I would agree as the dashed lines go to the surface and the faded areas are class E from 700' agl instead of the usual 1200'.

Since the reg specifically says "surface area" that means the dashed lines.



edit: too slow on the buttons.....but great minds think alike

 

[RussR]

I agree.

The "magenta faded line around an airport" is the 700 AGL Class E (i.e., the IFR transition area), not the surface area.

FWIW, Class E surface areas don't contain all instrument procedures, despite what the AIM says. None of the approaches for South Lake Tahoe (KTVL) are contained, even if you consider that to apply only once they have entered. For the VOR approach, for instance, the feeders cross the surface area, the IAF is on the boundary, and the procedure turn is outside.

All those segments are already contained in Class E airspace, the "1200 ft floor" type.

 

[midlifeflyer]

You have your answer, but note that the concept of the lateral boundaries of airspace designated for a airport appears in a number of FAR provisions, including one that was drummed into our heads pretty early in our primary training (although since it's a standard FR question for me, I know a lot of folks don't pick it up). It's the basic VFR weather minimums that require a 1,000' ceiling and 3 miles visibility to takeoff and land at a Class E or greater airport (the common error is thinking the rule applies only to towered airports).

 

[midlifeflyer]

I think I just found the answer to my own question. Order JO-7400.9y has an enumerated list of "Class E Airspace Areas Designated As A Surface Area" which appears to line up with dashed magenta lines or is a part time class D.

Some part-time Class Ds. Some part time Class D airports become surface area Class Es when the tower is closed; others become Class G.

 

[MAKG1]

Some part-time Class Ds. Some part time Class D airports become surface area Class Es when the tower is closed; others become Class G.

Though I don't know for sure that's the difference, the distinction appears to be whether or not the airport has AWOS or ASOS. No weather reporting = Class G.

 

[EdFred]

Though I don't know for sure that's the difference, the distinction appears to be whether or not the airport has AWOS or ASOS. No weather reporting = Class G.

KCMI - Class C.
Class G when Tower Closed

KGRR - Class C
Class E when Tower Closed.

Neither list an ASOS/AWOS Frequency, only ATIS, and an ASOS telephone number.

 

[Bill]

Ok, you can't operate a part 103 vehicle "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." 103.17

The AIM says:
"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."

The AIM wording would lead me to believe that the airspace referred to in 103.17 is limited to the "magenta dashed line circle plus sometimes a big dashed rectangle" and not the "magenta fade line around an airport" airspace. Am I right, or is it more insidious than that?

That is how I interpret it.

As do I. The two major hang gliding areas near here both have 103 pilots flying in the 700AGL class E areas.

 

[midlifeflyer]

Though I don't know for sure that's the difference, the distinction appears to be whether or not the airport has AWOS or ASOS. No weather reporting = Class G.

I have no idea of the reason either. But i don't think that's it. To sort of tag onto EdFred's post, there are airports that have AWOS or ASOS that don't broadcast it when the tower is open but do - over the ATIS frequency - when the tower is closed.

So, here's an example of a Class D airport that becomes Class G after hours and has weather reporting.

From the AFD for Front Range Airport (KFTG):

WEATHER DATA SOURCES: AWOS–3 119.025 (303) 261–9104.
COMMUNICATIONS: CTAF 120.2 ATIS 119.025 UNICOM 122.95
DENVER APP/DEP CON 128.25
TOWER 120.2 (1400–0400Z‡) GND CON 124.7
CLNC DEL 124.7 (1400–0400Z‡) DENVER CLNC DEL 121.75 (0400–1400Z‡)
AIRSPACE: CLASS D svc 1400–0400Z‡ other times CLASS G.
​

 

[Bill]

FWIW, Class E surface areas don't contain all instrument procedures, despite what the AIM says. None of the approaches for South Lake Tahoe (KTVL) are contained, even if you consider that to apply only once they have entered. For the VOR approach, for instance, the feeders cross the surface area, the IAF is on the boundary, and the procedure turn is outside.

IIRC, the dashed magenta lines are used only at airports that have precision approaches and as such inbound IFR aircraft need protection down to the DH, etc. And I would assume the dashed areas only enclose those portions of the approach that are below the 700AGL class E shelf.

 

[EdFred]

IIRC, the dashed magenta lines are used only at airports that have precision approaches and as such inbound IFR aircraft need protection down to the DH, etc. And I would assume the dashed areas only enclose those portions of the approach that are below the 700AGL class E shelf.

That's not entirely the case either as KBIV has an ILS, and it has the E700 floor. Someone once told me it was because there was scheduled airline flights, but I'm not so sure about that either. I've seen CESA's where I'm 99.9% sure there are no scheduled airline flights.

 

[MAKG1]

That's not entirely the case either as KBIV has an ILS, and it has the E700 floor. Someone once told me it was because there was scheduled airline flights, but I'm not so sure about that either. I've seen CESA's where I'm 99.9% sure there are no scheduled airline flights.

South Lake Tahoe has a Class E surface area (and a permanently closed tower), and has no part 121 traffic.

It did once, but that was decades ago.

Moffett is Class E at night and it has never had any scheduled airline service, and only very limited civil traffic.

 

[EdFred]

The more I think about it, I think it's just a random number generator that determines which places get E surface areas and which C/D's go to E/G.

 

[poadeleted20]

The AIM wording would lead me to believe that the airspace referred to in 103.17 is limited to the "magenta dashed line circle plus sometimes a big dashed rectangle" and not the "magenta fade line around an airport" airspace. Am I right,

Yes.

or is it more insidious than that?

No.

 

[Capt. Geoffrey Thorpe]

You have your answer, but note that the concept of the lateral boundaries of airspace designated for a airport appears in a number of FAR provisions, including one that was drummed into our heads pretty early in our primary training (although since it's a standard FR question for me, I know a lot of folks don't pick it up). It's the basic VFR weather minimums that require a 1,000' ceiling and 3 miles visibility to takeoff and land at a Class E or greater airport (the common error is thinking the rule applies only to towered airports).

If it was mentioned to me back in the 1970's, I have since forgotten. But I do recall that TCAs are a big deal.

 

[BillTIZ]

IIRC, the dashed magenta lines are used only at airports that have precision approaches and as such inbound IFR aircraft need protection down to the DH, etc. And I would assume the dashed areas only enclose those portions of the approach that are below the 700AGL class E shelf.

Not true, TPH (Tonopah NV) has surface Class E with no precision approaches.

 

[midlifeflyer]

If it was mentioned to me back in the 1970's, I have since forgotten. But I do recall that TCAs are a big deal.

...which is why I ask the question when I do flight reviews.

I recall TCAs too, but the difference is that Class E surface areas still exist by that name.

 

[midlifeflyer]

The more I think about it, I think it's just a random number generator that determines which places get E surface areas and which C/D's go to E/G.

I suspect it is a traffic issue of some sort, whether present or some time in the past, but I'd go with your answer

 

[poadeleted20]

The more I think about it, I think it's just a random number generator that determines which places get E surface areas and which C/D's go to E/G.

It's not random -- it's covered by an FAA Order. Wally Roberts explained it some time ago over on the Red Board, but I forget the details. The one requirement I do remember is weather reporting. IIRC, the presence of air carrier traffic is also a factor, and once it's done it's very hard to undo even if the air carrier pulls out.