Sorry if this has been asked before.  I didn't see an explanation in the manual under Airspaces.

The Airspaces information tab for KLEX lists multiple sources for Airspace information; Three are from Navigraph and last two appear to be from the default BGL file.  The Navigraph entries include lines labeled 'Multiple code: B', 'Multiple code: Z' and 'Multiple code: A'.

Could you tell me what those designations mean?  BTW, the information able Z and A are duplicates.

Interestingly, at least to me is that KCVG has dual entries for Class B, but doesn't have an entry for the inside zone like Lexington does.

Thanks,
Ernie

Edited April 10, 20233 yr by airernie

1) Double, overlapping displaying under LNM map - look at "Scenery Library", "Airspace Library", when both options "Simulator" and "Navigraph" are ticked they are double displayed, so it's necessary switch off one of them. I use Navigraph, as simulator's data can be obsolete

2) No they aren't duplicates. IMHO "Z" is an artificial designator (such zone doesn't exist in B-class around Cincinatti) displayed everywhere as it shows lateral borders of this B-class, so it will be showed at every real sector. But Z vertical limits are  SFC-A100, so it doesn't show real vertical borders of B-class. So, B-class is exactly where A-L designators shows.

What can Z designator be used for? For many things where lateral borders are required, for example - in B-class is speed limit for VFR traffic set to 200KIAS max, but it's not only in B-class zones but also below - down to the ground. So Z designator lets display on your navigation screen** whether you are inside B-class lateral border or not.
To understand idea of B-class in USA (only busiest big airports) you have to imagine reverse many-decker wedding cake - A-L zones have got different lower limits, but all ends up at 10000.
So flying VFR through L zone area (KCVG) but at A035 you are below B-class (not in vertical L limits), but still  FAA 200KIAS speed limit is required here as it's inside B-class lateral borders.

I hope this helps you better understand idea of B-classes in USA. 
FAA regulations and "philosophy" are slightly different than ICAO regulations 🙂 (I know this problem as a man from Europe)

Regards,
Piotr

**I've mentioned real aircraft's navigation systems for example, not only LNM exists ...  😛

 [edit]
ps. it's very nice showed on KCVG VFR Flyway planning chart (look at Skyvector) 
ps2. letter designators are probably generated automatically during Navigraph's conversion or taken direct from external sources.

 

Edited April 10, 20233 yr by ppgas

Thank you for the explanation. Not sure that I understand all of it, but I do more than I did and it will help in further studies..

Ernie

 

Wow! Thanks @ppgas! Just learned something new. Didn't know about the speed limit extending to the ground.

Alex

Just now, albar965 said:

Wow! Thanks @ppgas! Just learned something new. Didn't know about the speed limit extending to the ground.

 

But remember this is specific FAA's regulation so valid only in USA 🙂

Exactly 200KIAS limit in USA looks like:
1) for B class - in VFR corridors through B class and below B class area (everywhere)
2) for C and D classes - at or below A025 in radius of 4NM around primary airport of C/D class
3) exception of above - if minimum safe airspeed for aircraft is greater than 200KIAS it can operate in its minimum safe speed

See FAA CFR par. 91.117 regulation.

Some years ago I've migrated virtually to North America division on IVAO (online flying), so I had to learn some local USA and Canada regulations (BTW Canada's got own separate non-FAA regulations). For European pilot it's sometimes kind of "exotic" like LAHSO procedure  or OPTION procedure during performing circuit pattern.
But IMHO it's worth to know when someone is planning to fly over USA 🙂


Regards,
Piotr