Transponder on while taxiing

[Correcting]

I'm a fractional guy, so more often than not, I'm at an airport where I don't have to operate with the transponder on while taxiing. So when I get to a place that does have that requirement (like IAD), I sometimes forget to leave/turn it on. It's never been a big deal (yet) but I still hate when I forget.

My question for you controllers, is...

What if I just left my transponder turned on while taxiing at every controlled airport I go to so that I get in the habit of always having it on for taxi? Would it cause problems for controllers at those airports that don't have the ground radar in operation?

 

[Seadogrun]

I don't know about a problem with controllers, but from a pilots perspective there's nothing like going into an uncontrolled airport and getting an RA on short final.

 

[CA1900]

I don't know about a problem with controllers, but from a pilots perspective there's nothing like going into an uncontrolled airport and getting an RA on short final.

If your TCAS is working properly, that shouldn't happen.

 

[Spooky 2]

If your TCAS is working properly, that shouldn't happen.

Exactly right!

 

[Booker]

I could be mistaken, but I believe one major carrier's SOP is to have it on from push to parking, regardless.

 

[atl pilot]

Since I work at ATL (where you have to have it on) I say leave it on....but I am biased. There are days when I feel like I am the transponder-police. This is for your safety. The AMASS (safety feature on the ground radar) can only work truly properly if its on.

 

[Lrjtcaptain]

At ORD we want it on because of ASDE-X but you would be suprised at how many planes forget to turn it on. Now in low visibility we may get a bit edgy about it if one of our planes comes up missing on the ASDE-X however in okay visibility we can look at the window and see you. The main reason we want it on is becuase the built in saftey logic which doesn't work all that great but with it on if you go across a protected area it will imediatly alert us to a potential conflict I.E. landing or departing traffic that may hit you if you continue to cross an active runway while lost. I'm not a big fan of using ASDE-X other then its saftey logic. If you forget to turn it on, so what....more then likely the controller knows where you are. As for uncontrolled fields etc.... Well, my first airport was a class D. We had a few issues with aircraft on final asking if someone was on short final when in fact someone in the runup had there transponder on. I know it shouldn't be an issue but it sometimes is where a plane goes around due to an RA but its a small issue. Leaving the transponder on wont really hurt anyone but can cause some issues sometimes with some TCAS systems. I wouldn't worry about it. I would do what ever your company does. If your at ATL or ORD or wherever that they want you to turn it on and you forget, we will remind you but its not like "hey idiot turn on your transponder." We know most airports dont have the requirment and we know that most pilots turn it off when the clear the runway. Our ATIS has a "ASDEX operations are in affect, pilots shall have transponder with mode c on while operating on the airport." Our ATIS is like 5 minutes long. I personally don't expect every pilot to remember the little snipit of info. Do what you want, but remember, I don't know any controller that is going to get upset, they will just remind you. I remind 5-10 planes an hour and I never unkey and say idiot. Im a pilot myself. I was trained to turn it off when I land. After a while it will be come so routine with the changes in equipment that its going to be the norm to leave it on. You are in a grace period. Don't worry about it, who cares.

 

[SSDD]

What about the likelyhood of two airplanes with the same code? Say, an airplane comes in with a certain code and sits for an hour or so, in the mean time another airplane comes in, or is ready to depart, and is issued the same code.

 

[Thedude]

Or like in PVG where they dont even give you time to clear the rwy before they are crying about turning of the transponder

 

[Lrjtcaptain]

Well, if a plane landed with the same code and he is at the gate the transponder should be off. Also we he arrived, the system should remove his strip from the ARTS and the NAS and any other plane with the same transponder will then show up. The problem with ASDEX in our case is it doesn't respond with any primary targets so even if you were to taxi with a 1200 code then at least we can see a target in low visibility and the saftey logic would in turn work. Planes taxi with the wrong codes all the time, we don't get their data blocks but at least we can see a target which is better then nothing.

 

[atl pilot]

The ASDE will show a "DUP ID" in the time share of the data block, but will continue to show your callsign as well. This happens at ATL all the time, nothing unusual.
Nice post....LRCapt. - great expalnation.

 

[brett]

Some transponders, "time-out"

A quick note to add here for controllers, some of you may already know. Some transponders shut off automatically on the ground in a few minutes even after you've manually turned them on.

I'm pretty good about remembering mine when I start out at CLT, ATL, etc, but it's hard to catch the automatic time-out and turn it back on immediately when you're busy taxiing.

 

[Makesheepnervus]

Landed at toronto the other day and switched the xpndr from "TA/RA" to "On" (No mode C) when we left the runway. As we taxied into the ramp at Landmark the Ground controller told me to turn the xpndr off. Was this because we were now leaving his jurisdiction or because they never wanted it on in the first place?

Also, my understanding of leaving the transponder on while taxiing was to just have it in the "on" position, vs the "Alt" or mode C position, which is correct?

 

[Booker]

Also, my understanding of leaving the transponder on while taxiing was to just have it in the "on" position, vs the "Alt" or mode C position, which is correct?

It's only half an answer, but some ASDE airports specify in the ATIS to operate the transponder in Mode C. See Lrjtcaptain's post, number 7.

 

[CA1900]

Landed at toronto the other day and switched the xpndr from "TA/RA" to "On" (No mode C) when we left the runway.

If you're deliberately disabling the Mode C, I don't recommend that. With no altitude information, tower displays and TCAS displays at all altitudes will show you as a potential target (and call out a "Traffic, Traffic" if the trajectory is right). Many tower displays (those without the new ground radar) will filter out traffic on the ground, but they can't do that without altitude information.

The "TA ONLY" mode would be more appropriate for what you're trying to do, but changing it really isn't necessary, as that mode is selected automatically below a certain altitude AGL anyway.

Short version: If you have a transponder on, have Mode C on as well, unless it's giving erroneous altitude information.

 

[jackpilot]

Hey guys,

I don't troll the ATC forums much, however I saw a reply from an ORD controller.

Just wanted to say, you guys are absolutely phenomenal...day in, and day out.

I'm sure being an ATC controller is mostly a thankless job. Like most jobs. But from an airline guy who has been flying out of there for years, you guys are awesome and we all appreciate you very much!

 

[Makesheepnervus]

OK thanks, the memo I had seen on this indicated I should leave the transponder in the "on" postition only with no mode C.

Leaving the Mode C on makes more sense to me given the circumstances.

 

[CallmeJB]

After you hear Transponder On in the ATIS, rip the corner off of some piece of paper and stick it on the transponder switch. Done! Now you'll never forget. If you're a super nerd like me, when you reach to turn it off and see the piece of paper, move the paper to something in the shutdown check (seat belt sign, windshield heat); then you'll remember to turn it off after you park.

Sounds dorky but it works every time.

 

[avbug]

I could be mistaken, but I believe one major carrier's SOP is to have it on from push to parking, regardless.

You'd be mistaken. Our policy is to turn it on (unless required otherwise) while entering the runway for takeoff, and it goes off as part of the after landing flows.

 

[Booker]

You'd be mistaken. Our policy is to turn it on (unless required otherwise) while entering the runway for takeoff, and it goes off as part of the after landing flows.

Thanks for the correction. I didn't realize you flew for the airline whose name I didn't mention.

Not that it matters, but I just checked one of the flight manuals for said airline, and indeed the transponder is selected on at push and isn't selected to standby until parking.