Transponders off at OSH - why?

dans2992

dans2992

En-Route
Joined
Jan 7, 2013
Messages
4,016
Display Name
Display name:
Dans2992
Subject line says it all. Can't ATC just ignore/filter the mass of pixels on their screen? Wouldn't ADS-B work OK even at that level of traffic?

Sure, it might not do you much good right up next to the field, but the NOTAM asks for them off within 30nm. What's the thinking there?
 
I think the density of the aircraft triggers non-stop traffic alerts for ATC.
 
Even if the planes are VFR, squawking 1200?
 
Dan,

ADS-B works at that level of traffic even with your transponder off. Our GDL88 / GTN650 setup did at KOSH anyway...FWIW.

Jim
 
dans2992 said:
Subject line says it all. Can't ATC just ignore/filter the mass of pixels on their screen? Wouldn't ADS-B work OK even at that level of traffic?

Sure, it might not do you much good right up next to the field, but the NOTAM asks for them off within 30nm. What's the thinking there?
Click to expand...

This was an issue for Center radar displays, I don't know that it's a problem with terminal radar systems. Transponders off has been part of EAA procedures for a long time. Could be the folks that are responsible for this stuff now are carrying it forward because they don't know why it came to be the way it is and they are hesitant to mess with it.
 
Related question....

I will be at OSH this year and thought it would be interesting to fly over the field at 4,500' or so for a aerial photo pass. For that I would be above Class D and not intending to land, though I would probably go out a little west of Ripon and descend into the VFR arrival que.

Would I leave the transponder on for that, even though I am within 30 miles of the field? I'm thinking yes, so that ATC can see what my altitude is. I would then turn it to standby as soon as I turn back in toward Ripon.
 
Here is my KOSH photo, no need to get your own.
 

Attachments

  • image.jpg
    image.jpg
    1.7 MB · Views: 160
flytime said:
Related question....

I will be at OSH this year and thought it would be interesting to fly over the field at 4,500' or so for a aerial photo pass. For that I would be above Class D and not intending to land, though I would probably go out a little west of Ripon and descend into the VFR arrival que.

Would I leave the transponder on for that, even though I am within 30 miles of the field? I'm thinking yes, so that ATC can see what my altitude is. I would then turn it to standby as soon as I turn back in toward Ripon.
Click to expand...

Yes, there's no problem with doing that and frankly as Steve points out you can probably leave the transponder on.

I do exactly this a dozen times or more during the show giving rides to volunteers. Takeoff and follow the departure (150 heading down low) procedure climb up to 4500 or so on the far side of the lake. Do a few passes over the show and then either fly the normal (if the person is a pilot and hasn't done the Ripon arrival yet) or the warbird approach back in.
 
sourdough44 said:
Here is my KOSH photo, no need to get your own.
Click to expand...
Or mine...

2014-07-29%2005.47.02.jpg
 
I can answer this, it is a pretty trivial answer, but why can't you ask Oshkosh questions over in the Oshkosh subforum?

Thanks,

Jim
 
All these pictures sure look great. T-minus 11 days till departure! :)
 
weirdjim said:
I can answer this, it is a pretty trivial answer, but why can't you ask Oshkosh questions over in the Oshkosh subforum?

Thanks,

Jim
Click to expand...


Ok, sorry, didn't realize that existed.
 
mkosmo said:
Getting in Saturday? We're planning to arrive Sunday.

Sent from my Nexus 9 using Tapatalk
Click to expand...
Saturday will be with our son and his wife in Minnesota.

We should be in the N40 by noon Sunday.

Unless the country looks like it does today. lol
 
Dan

Call the local tower and ask for a tour...probably be some paperwork, or ask a cfi to arrange it. get a first hand explanation why no transponders and no talking for KOSH arrivals.
 
They can filter the 1200 code but the "position symbol" or square still remains creating excessive clutter.
 
Too much clutter on the screen,also love to listen to ATC when none of the pilots are supposed to be not talking.
 
Hmmm. Sounds like a good way to civily protest the way the FAA is continuing to bend EAA over for their taxpayer-supported services during the convention week.

Crap, I've got ADS-B out. The traffic service doesn't work properly, but the part that broadcasts my name and address sure does.

"Never mind..." ;)
 
Jay Honeck said:
Hmmm. Sounds like a good way to civily protest the way the FAA is continuing to bend EAA over for their taxpayer-supported services during the convention week.

Crap, I've got ADS-B out. The traffic service doesn't work properly, but the part that broadcasts my name and address sure does.

"Never mind..." ;)
Click to expand...

I just have to grin at this. Y'all bought into the ADS-B, spent the money, toed the line.

Now - when it's far too late, you want some kind of civil protest of the over-reach of the FAA and their handling of anything related to GA. It's one of those schadenfreude moments that only come along in rare instances.

Welcome to 1984. You're only 31 years too late. :rolleyes:
 
ADS-B or not, when you have that many aircraft arriving at once, their codes and tags would overlap so much that you wouldn't be able to make out who's who. That's the reason why in standard formations, lead squawks and everyone else is on standby. Just too much clutter.
 
Velocity173 said:
ADS-B or not, when you have that many aircraft arriving at once, their codes and tags would overlap so much that you wouldn't be able to make out who's who.
Click to expand...

Transponders-off within 30 NM is part of the VFR arrival procedure. These aircraft aren't receiving radar services so there are no tags and their VFR squawk is not displayed.

That's the reason why in standard formations, lead squawks and everyone else is on standby. Just too much clutter.
Click to expand...

Not really, formation flights are treated as a single aircraft so there's no need for any other aircraft to be squawking. The only change is adding a mile to the appropriate minima for a standard formation. Nonstandard formations are often assigned individual codes.
 
roncachamp said:
Transponders-off within 30 NM is part of the VFR arrival procedure. These aircraft aren't receiving radar services so there are no tags and their VFR squawk is not displayed.



Not really, formation flights are treated as a single aircraft so there's no need for any other aircraft to be squawking. The only change is adding a mile to the appropriate minima for a standard formation. Nonstandard formations are often assigned individual codes.
Click to expand...

Lol! Yes Steven, I aware of the arrival procedure. The answer I gave above for not having them on (1200) is straight from a tower sup who will be working OSH this year. I was giving a hypothetical if you did have people receiving service, their tags would be all over the place.

I also realize a formation is controlled as a single aircraft. I agree there would be no point in assigning a squawk to wingman in a standard formation. I was implying that if you did, you'd have serious overlap. Obviously in a nonstandard formation you need to know the boundary of the formation so seperate squawks are given. We only issued lead and trail.
 
Velocity173 said:
Lol! Yes Steven, I aware of the arrival procedure. The answer I gave above for not having them on (1200) is straight from a tower sup who will be working OSH this year. I was giving a hypothetical if you did have people receiving service, their tags would be all over the place.
Click to expand...

Radar services for VFR arrivals is not the issue. Even if the transponders-off procedure was not in place VFR arrivals would still not be receiving radar services.
 
roncachamp said:
Radar services for VFR arrivals is not the issue. Even if the transponders-off procedure was not in place VFR arrivals would still not be receiving radar services.
Click to expand...

Sure, I'd agree with that as well. All I'm saying is 1. Transponders off is to prevent 1200 code clutter and 2. if you were to try and use ADS-B in/out there would be so much clutter on both sides that it would be of little value to the pilot or controller. Best to keep your eyes outside than to look at a maze of alerts going off on a small screen.
 
Velocity173 said:
Sure, I'd agree with that as well. All I'm saying is 1. Transponders off is to prevent 1200 code clutter and 2. if you were to try and use ADS-B in/out there would be so much clutter on both sides that it would be of little value to the pilot or controller. Best to keep your eyes outside than to look at a maze of alerts going off on a small screen.
Click to expand...

There would be no 1200 code clutter even if the transponders were on as the codes are not displayed. As I said in an earlier message, this procedure goes back a long time, long before this airspace was forced on MKE approach. I first questioned the reason behind it in 1984, when ZAU had the airspace.

For radar data processing purposes ARTCC airspace is divided onto Radar Sort Boxes. Each RSB is assigned primary and backup ARSRs and altimeter setting sources. IIRC there is a limit to how many transponder returns can be displayed within a single RSB. That shouldn't be an issue for ZAU today as MKE approach has had that airspace from 13,000 to the surface since 2008.
 
You must log in or register to reply here.
Back
Top