Transponder Standby Mode

[MarineGrunt]

Yeah, Grunt, it takes a little time to "warm up". Just what is warming up, I don't know, but as I understand these little GA transponder boxes, everyone I have operated, the reply light come on when you first turn from "Off" to "SBY, and stays on for a 20-30 second period, then goes out. This is the warm-up time. The light going out indicates it is warm and ready to reply.

Great. Thats the answer I was looking for. Thanks!

 

[Vector4fun]

Re: Hey Vector

Whats up with ATC tellin us to switch sqawk codes in flight sometimes? Like just get a hand off then they are like Colgan sqawk 4513. Seems like it happens more often when we get big short cuts, or is that just my imagination?

If it's happening shortly after you get handed off to a sector or facility associated with a different Center, then most likely, the HOST has recognised that you're sharing the same beacon code with another flight in, or proposed for that Center. So HOST decided you should get a new, un-shared beacon code all your own.

My facility (AUS) is tied into ZHU, but we get arrivals from the North that have just left ZFW's airspace, so often, we get an arrival strip about 20 minutes early, then a new beacon code for the arrival about 5 minutes before they get to our airspace, and often, the ZHU controller is just getting those arrivals on the new code as they're being handed off to us. Never happens when the arrivals are coming from another direction, because they've either been changed long ago, or originated in ZHU's airspace, or never needed to change.

Some folks aren't aware, but there's days when the NAS is really busy, we run short of transponder codes, and have to make a keyboard entry to request one when you call to pick up your clearance. Normally, a discrete code is automatically assigned when the proposal is generated 30 min before your P-time. One reason for you on-demand folks to try to keep from filing multiple flight plans, and tell us when you decide not to use one, so we can remove it.

Also, sometimes a flight plan just gets so botched up, or there's a processing problem, it's just easier to drop the old flight plan, and enter a new one, than to try to fix the old one. That will generate a new code. Happens more often with VFRs or military though, than with scheduled IFR traffic with canned flight plans.

On the local level, each terminal facility gets it's own code bank. My facility has 02xx. SAT and GRK have their own as well. Within those code banks are catagories, depending on local programming. For example, 0201-0207 are reserved for local operators which we have an LOA with. Police, Medevac, traffic watch etc. They keep the same code day after day. 0210-0257 are local VFR codes. 0260-0267 are local IFR codes. They differ because they trigger the Minimum Safe Altitude Warning (MSAW) processing. The VFR codes won't, but the Conflict Alert will still function with the VFR codes. If I gave you a local VFR code, and then you asked for a local IFR clearance to descend through low clouds, I'd have to re-assign one of our local IFR codes which has MSAW processing when I gave you the IFR clearance to be 100% legal. (Doesn't always get done...) Also, depending on local programming, some codes are only generated from some keyboards. Some show you in "arrival status" vs "departure status" or some such, which is useful to the programmers who may have a traffic count or other patches installed etc., but is of little interest to the controllers, and even less to the pilots.

Somebody from automation could write a book about this stuff, and I don't understand a tenth of it, but somehow, it most often works. But when it fails, it drives us all nuts.....

 

[flyifrvfr]

Then if they tell you to change transponder codes while you're inside the ADIZ, you're screwed, because you're almost certainly going to get painted at least once before you get the correct code set in whether you go to standby or not.

If they tell you to switch codes while inside of the ADIZ then the new code you are issued is the correct code for that moment.I have yet in the two years the ADIZ has been around,never been told to change codes.They have it down to a science now.