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When descending on an ILS you can descend to 100' above the TDZE if you have the approach lighting system in sight. Cody Johnson wrote an article explaining how one pilot mis-interpreted what the rules allowed him to do, descended below 100' when there were obstructions in the way and crashed into a hill. (https://iflyamerica.org/misunderstanging_part91.asp )

Section 91.129(e)(3), Operations in Class D Airspace, is also extremely applicable in this accident. It says, 'An airplane approaching to land on a runway served by a visual approach slope indicator shall maintain an altitude at or above the glide slope until a lower altitude is necessary for safe landing.'

Class C and B incorporate Section 91.129(e)(3) by reference, so the rule applies in that airspace as well. It doesn’t specifically apply to operations at airports in Class E airspace.

My question is are there any ILS approaches in Class E airspace? Is there a a rule that prohibits them, or conversely, only allows them when there is a tower?

DeltaLima
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JScarry
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4 Answers4

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There are plenty of ILS approaches in Class E surface area (e.g. KCLM, KHQM, KPWT). In fact the presence of an ILS will usually require that some kind of controlled airspace extends to the surface. For an untowered airport this means a Class E surface area.

Steve Kuo
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Visalia, CA (KVIS) is an uncontrolled airport with a Class E surface area and an ILS with 200' minimums.

pericynthion
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  • Now that I know that there are some, I wonder why the descent rule doesn’t apply to them. – JScarry Feb 23 '17 at 23:56
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    ILS approaches are even possible in Airspace G. – pcfreakxx Feb 24 '17 at 11:36
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    @pcfreakxx please name one. I ask because the FAA has ruled that IFR is Class G is illegal (see https://www.faa.gov/about/office_org/headquarters_offices/agc/pol_adjudication/agc200/interpretations/data/interps/2016/Lamb%20-%20(2016)%20Legal%20Interpretation.pdf) – Steve Kuo Feb 24 '17 at 22:25
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    @SteveKuo -- no, IFR in G without a clearance is illegal. – UnrecognizedFallingObject Feb 25 '17 at 01:01
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    @SteveKuo Actually you need a RMZ (or airspace F). One example is EDGS aerodrome. – pcfreakxx Feb 25 '17 at 08:27
  • @Steve Kuo That letter specifically says that the FAR's are silent on the issue. The issue is addressed in this question. The example given is where the pilot took off into IMC from uncontrolled airspace when ATC refused clearance. They could not provide separation and IMC meant he couldn't see-and-avoid so they said it was reckless to take off without clearance. – TomMcW Feb 25 '17 at 19:48
  • @pcfreakxx RMZ and class F don't exist under FAA – TomMcW Feb 25 '17 at 19:48
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    @TomMcW But they do exist according to ICAO – pcfreakxx Feb 25 '17 at 19:49
  • @pcfreakxx -- member states are free to have documented variances from ICAO's rules – UnrecognizedFallingObject Feb 25 '17 at 22:46
  • @UnrecognizedFallingObject Did I say anything else?? NO! But my example was EDGS which is in germany and therefore regulated by ICAO – pcfreakxx Feb 25 '17 at 22:48
  • @pcfreakxx -- we're trying to point out that pointing out a German example isn't really relevant on a question tagged [faa-regulations] m8 – UnrecognizedFallingObject Feb 25 '17 at 23:29
  • @SteveKuo ILS 7 to LPR. The ILS takes you down to 200' AGL, but class E ends at 700 AGL. – NathanG Feb 27 '17 at 07:51
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    @UnrecognizedFallingObject ('s first comment): IFR anywhere without a clearance is illegal. – Vikki Feb 04 '20 at 03:45
  • @SteveKuo -- re"@pcfreakxx please name one."-- an example is KCVO-- see https://flightaware.com/resources/airport/KCVO/IAP/all/pdf – quiet flyer Jun 08 '20 at 23:56
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Around airports, instrument approaches are what class E is all about. That's what results in the "keyhole" shape of class E 700ft and surface area extensions.

Class E surface area surrounding an airport is usually used for airports that do not have a tower or at times when the tower is not operating.

From AIM 3-2-6 §e.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.1

<p>(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).</p>

But Class E extensions are also used to protect approaches to towered airports in B,C, or D areas.

AIM 3-2-6 §e.2. 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.1

Anywhere there are instrument approaches not protected by class B, C, or D airspace you can expect a class E extension. Anywhere aircraft on approach are expected to go below 1000 feet there will usually be a class E surface extension.2

1FAA Aeronautical Information Manual[PDF]

2 Russ Roslewski, How are Class E surface area extensions determined?

TomMcW
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KPNE has an ILS for their 24 runway they are class D airspace between 1100-0400Z and class E all other times. The approach, as far as I know, remains on while the airport is class E.

Dave
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