Transponder on while taxiing

[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.