Welcome Guest. Sign in or Signup

6 Answers

Additional Control Area Limit

Asked by: 3451 views Instrument Rating

On the low IFR chart, what's the function of the brown "additional control area limit"? I see often this brown circling some airports on the chart but cannot identify its purpose. At first I thought it signified the E airspace but it doesn't look like it given that many airports surrounded by E airspace on the VFR chart do not have the circle line on the low IFR chart.

Ace Any FAA Written Test!
Actual FAA Questions / Free Lifetime Updates
The best explanations in the business
Fast, efficient study.
Pass Your Checkride With Confidence!
FAA Practical Test prep that reflects actual checkrides.
Any checkride: Airplane, Helicopter, Glider, etc.
Written and maintained by actual pilot examiners and master CFIs.
The World's Most Trusted eLogbook
Be Organized, Current, Professional, and Safe.
Highly customizable - for student pilots through pros.
Free Transition Service for users of other eLogs.
Our sincere thanks to pilots such as yourself who support AskACFI while helping themselves by using the awesome PC, Mac, iPhone/iPad, and Android aviation apps of our sponsors.

6 Answers



  1. Mark Kolber on Feb 03, 2017

    Sometimes it helps to mention an airport where you have seen it on the off-chance that looking at it might give a clue.

    When the FAA reclassified airspace into today’s alphabet soup in the early 90’s there were some areas that didn’t quite fit. Offshore control areas were one and were designate by the names Control ###. Take a look at this chart snippet. Is this what you are referring to?
    https://skyvector.com/?ll=44.53812173661153,-124.14083862509926&chart=302&zoom=2&fpl=JAMIE%203750N07549W

    +1 Votes Thumb up 1 Votes Thumb down 0 Votes



  2. Lemontree on Feb 03, 2017

    I’m sorry Mark. I wanted to include the picture or the link, but I didn’t know how to do it and I still don’t know.The one I had in mind was “Bowman Regional(BWW).” If you type the three letter and click on the “go” button in Skyvector, you’ll see it. Not just that airport. Many airports around it have the brown circle surrounding them.

    0 Votes Thumb up 0 Votes Thumb down 0 Votes

  3. Best Answer


    EAD on Feb 03, 2017

    If you notice, the BWW airport underlies the MOA. In this case the Powder River 3 Low MOA starts at 500 AGL EXCEPT for the area within the brown circle, where it starts at 2000 AGL.

    +1 Votes Thumb up 1 Votes Thumb down 0 Votes



  4. Lemontree on Feb 04, 2017

    That was why!. Thank you EAD>

    +1 Votes Thumb up 1 Votes Thumb down 0 Votes



  5. Mark Kolber on Feb 04, 2017

    Isn’t that a magenta circle? Either way, see how easy it is with a chart reference? A solid circle with some text pointing to it. The text usually tells you exactly what it is.

    0 Votes Thumb up 0 Votes Thumb down 0 Votes



  6. Russ Roslewski on Feb 05, 2017

    Mark he’s looking at the Low Enroute chart, where it looks brown to me (versus magenta on the VFR sectional).

    0 Votes Thumb up 0 Votes Thumb down 0 Votes


The following terms have been auto-detected the question above and any answers or discussion provided. Click on a term to see its definition from the Dauntless Aviation JargonBuster Glossary.

Answer Question

Our sincere thanks to all who contribute constructively to this forum in answering flight training questions. If you are a flight instructor or represent a flight school / FBO offering flight instruction, you are welcome to include links to your site and related contact information as it pertains to offering local flight instruction in a specific geographic area. Additionally, direct links to FAA and related official government sources of information are welcome. However we thank you for your understanding that links to other sites or text that may be construed as explicit or implicit advertising of other business, sites, or goods/services are not permitted even if such links nominally are relevant to the question asked.