Question on Sectional Chart Airspace

R

RobH

Filing Flight Plan
Joined
Oct 11, 2022
Messages
2
Display Name
Display name:
Rob
I am currently working through an online ground school for PPL and finishing a section on airspace. To practice, I pulled out the Detroit sectional chart and started going over the various airspace surrounding the airports. I came to MBS INTL (MBS) and was confused with this one. To me, it appears to be Class D airspace up to 3200; however there is another airspace sitting on top of it from SFC to 10,000. (I would post a link to the chart, but not allowed to do that yet.)

Can anyone explain what is going on with this airspace? I am sure it is something simple that I am just overlooking.

Thanks,
Rob
 
MBS is a Class Delta SFC-3200. The airport is busy but not busy enough to be a Class Charlie so there is a TRSA which is a radar service area. TRSA usage is voluntary and not required, however it would show good pilot judgment by using that. TRSA airspace coverage is SFC-10,000 in the inner ring and 3000-10000 in the outer ring. If you are transiting the Delta airspace, you are required to be in communication with either the TRSA or MBS tower. If you are transiting the TRSA it is optional. Hope that helps!
 
Thanks everyone for the very quick replies. I will review the information on TRSA as I have not seen that yet.
 
RobH said:
Thanks everyone for the very quick replies. I will review the information on TRSA as I have not seen that yet.
Click to expand...

Terminal Radar service area, optional usage airspace. Will be a question on your checkride, as long as you use the words radar service and optional but recommended to use, your examiner will move onto the next question. I use them if I have weather or in flight questions, and/or I feel like talking to ATC. Sometimes you want to be free and that means silence haha
 
I've been rusty a while now... TRSA's were a thing back when I was active but I thought they had gone away with the alphabet airspace coming in.
I suppose not.
I guess I should do a more thorough airspace review myself!
 
Brad W said:
TRSA's were a thing back when I was active but I thought they had gone away with the alphabet airspace coming in.
Click to expand...

Almost all of them are gone. They left a few because it's the FAA, and they aren't happy if something is unambiguous. ;)
 
RobH said:
Thanks everyone for the very quick replies. I will review the information on TRSA as I have not seen that yet.
Click to expand...

Kalamazoo and Muskegon also have them.
 
Jeff Oslick said:
Almost all of them are gone. They left a few because it's the FAA, and they aren't happy if something is unambiguous. ;)
Click to expand...

There are a lot more of them today than there were 20 years ago. I think four back then - PSP, GTF, FAR, and maybe AEX? Now there are around 30.
 
Flying Keys said:
There are a lot more of them today than there were 20 years ago. I think four back then - PSP, GTF, FAR, and maybe AEX? Now there are around 30.
Click to expand...

All the ones in Michigan have been around since before 2002, so more than 4 for sure. I am not aware of any that have been created since they went to A/B/C/D. I would go as far to bet that NONE have been created in the past 20 years. So all the ones around now were around then too. You just didn't encounter them, probably because you didn't have charts for the entire US like we do now.

Current list:
https://en.wikipedia.org/wiki/Terminal_radar_service_area
 
EdFred said:
All the ones in Michigan have been around since before 2002, so more than 4 for sure. I am not aware of any that have been created since they went to A/B/C/D. I would go as far to bet that NONE have been created in the past 20 years. So all the ones around now were around then too. You just didn't encounter them, probably because you didn't have charts for the entire US like we do now.

Current list:
https://en.wikipedia.org/wiki/Terminal_radar_service_area
Click to expand...

I did have WAC charts for the entire country in the mid to late 90s - I’ll have to dig them out of storage, for curiosity sake. Would be interesting to see how the NAS has developed since then.
 
TRSAs aren't controlled airspace. They were hoped to have been gone by now either grown up into class C or otherwise disposed of. Problem is many still don't meet the requirements for class C. Others have been subsumed. The DC tri-area class B was subsumed out of a TCA, TRSA, and an ARSA.

The other oddity that seems to have been removed from charts is the little R symbol that says radar services are available which were even more nebulous than the TRSA. There are a few airports like RDG that used to bear this mark but now you'd ever know unless you looked up the entry in the chart supplement (or perhaps the sectional chart margins for those still using paper charts).
 
Then there’s places like KCYS where if you try cold calling tower inbound they switch you over to Cheyenne approach and won’t talk to you until you do. Feels like they should have a TRSA at least.
 
kaiser said:
Then there’s places like KCYS where if you try cold calling tower inbound they switch you over to Cheyenne approach and won’t talk to you until you do. Feels like they should have a TRSA at least.
Click to expand...

Same thing at Reading, PA...the little Delta that thought it could, but actually shouldn't, doesn't, and never did.
 
To the OP (Rob), you're going to want to get comfortable with the sectional chart legend. Every single symbol and airspace depiction is called out there. Even if you're not familiar with what a TRSA is, it would've given you the name which you could then research. Deep dives on sectionals are excellent practice, keep at it! Back in the 90's during my training, I would literally come to bed with the SFO sectional and study it until falling asleep. This was back in the day before skyvector and EFB's....I was always curious was was north of Redding, so one day I bought the Klammath sectional just 'because' and was blown away by what existed to the north.

Skyvector was an amazing addition, but part of me was just a TINY bit sad that electronic charting meant paper charts' time were limited. I've fully accepted it now, but there was something special about taking a look at a new area for the first time on a paper sectional. The pros of EFB's 100% outweigh the cons, but in much the same way as IFR pilots earn their view of breaking out through the tops during a climb, I do remember the joy as a student pilot of seeing a new area for the first time on a sectional. Wonder if anyone else did the same?
 
flyingron said:
TRSAs aren't controlled airspace. They were hoped to have been gone by now either grown up into class C or otherwise disposed of. Problem is many still don't meet the requirements for class C. Others have been subsumed. The DC tri-area class B was subsumed out of a TCA, TRSA, and an ARSA.

The other oddity that seems to have been removed from charts is the little R symbol that says radar services are available which were even more nebulous than the TRSA. There are a few airports like RDG that used to bear this mark but now you'd ever know unless you looked up the entry in the chart supplement (or perhaps the sectional chart margins for those still using paper charts).
Click to expand...
Yeah, they don’t establish Controlled Airspace. But have you ever seen one that wasn’t in Controlled Airspace?
 
coma24 said:
To the OP (Rob), you're going to want to get comfortable with the sectional chart legend. Every single symbol and airspace depiction is called out there. Even if you're not familiar with what a TRSA is, it would've given you the name which you could then research. Deep dives on sectionals are excellent practice, keep at it! Back in the 90's during my training, I would literally come to bed with the SFO sectional and study it until falling asleep. This was back in the day before skyvector and EFB's....I was always curious was was north of Redding, so one day I bought the Klammath sectional just 'because' and was blown away by what existed to the north.

Skyvector was an amazing addition, but part of me was just a TINY bit sad that electronic charting meant paper charts' time were limited. I've fully accepted it now, but there was something special about taking a look at a new area for the first time on a paper sectional. The pros of EFB's 100% outweigh the cons, but in much the same way as IFR pilots earn their view of breaking out through the tops during a climb, I do remember the joy as a student pilot of seeing a new area for the first time on a sectional. Wonder if anyone else did the same?
Click to expand...
Putting an @ here to get @RobH ‘s attention. Did you ever take a https://aeronav.faa.gov/user_guide/20220908/cug-complete.pdf to bed with you and the Sectional for a ménage a trois?
 
luvflyin said:
Yeah, they don’t establish Controlled Airspace. But have you ever seen one that wasn’t in Controlled Airspace?
Click to expand...
In a word, yes. The one depicted in the original post shows pieces of the TRSA surface area encompassing area outside the class D. These are class G still. Most of it is within the class D or the overlying class E but not all.
 
flyingron said:
In a word, yes. The one depicted in the original post shows pieces of the TRSA surface area encompassing area outside the class D. These are class G still. Most of it is within the class D or the overlying class E but not all.
Click to expand...
Yup. Those short extensions of the surface part of the TRSA look just like Class D Surface Area Extensions. They’ll do that when they are very short, I don’t remember the number. Otherwise they make Class E Surface Area Extensions to the D. I think something may have got mixed up in Charting.
 
flyingron said:
In a word, yes. The one depicted in the original post shows pieces of the TRSA surface area encompassing area outside the class D. These are class G still. Most of it is within the class D or the overlying class E but not all.
Click to expand...
From JO 7210.3CC I highlighted the last sentence
12−1−3. TRSA
a. TRSAs are not officially designated by airspace action and were established solely to define an area within which a separation service will be provided. Therefore, at all TRSA locations it is intended that facilities must provide the full extent of TRSA services throughout the entire advertised TRSA area. Although the TRSA area extends downward to the surface within the surface area of Class D airspace at the primary airport, a base should be established outside this surface area of Class D airspace to permit free movement of nonparticipating aircraft. The base of the TRSA must not be below the base of an associated Class E airspace.
 
Well, something is in disagreement. The TRSA sticks out beyond the class D. While it looks like class D/E extensions the class D is perfectly circular without extensions.

The TSRA I'm familiar with (MDT) had surface area beyond the class D (it has extensions, but the TRSA extensions are even LONGER).
 
flyingron said:
Well, something is in disagreement. The TRSA sticks out beyond the class D. While it looks like class D/E extensions the class D is perfectly circular without extensions.

The TSRA I'm familiar with (MDT) had surface area beyond the class D (it has extensions, but the TRSA extensions are even LONGER).
Click to expand...
Yeah. My guess is the surface part of the TRSA Is coincident with old Control Zone. The radius of the round part of it looks like 5 SM. That would be 4.3 NM, the radius of the the typical Class D. This Class D is 4.8 NM. That was probably big enough to do away with the little nubby extensions. They just never got around to redrawing the TRSA when they established the new D.
 
Last edited:
That makes sense. I really hate that control zones went away. Now we just have "surface area of controlled airspace designated for an airport."
 
You must log in or register to reply here.
Back
Top