There are a lot of lines on sectional charts. It’s confusing to know which ones we must pay attention to or not. This should help demystify those lines. Of course you can look at the sectional chart’s legend to see what the lines are but that doesn’t make it clear what they really mean to us.
Most lines are not restrictive. Many are either land features (like powerlines), some are cartographic like longitude lines or elevation lines, and the rest define airspace of some sort.
These charts are intended to supplement what’s in Chapter 9 of the PPG Bible but can help anyone better understand U.S. Aviation Sectional charts, a treasure of information that sometimes can be buried a bit too well. Full resolution versions of these will be used in an upcoming issue of Powered Sport Flying Magazine.
Here’s a good reason to always get new charts or go online. The Double Eagle, AEG, airport (below) does not now have a tower. But it will!!! It’ll be in the next issuance of the chart. Consequently, there will be D airspace around it out to 5 miles. If you casually came in to fly nearby and didn’t have the new chart, you’d have no way of knowing you’re committing an FAR violation.
This is a clean example of B airspace. Most are shaped weirdly to accommodate the airflow patterns around an area.