What to do when ATC asks you to switch to ‘ground mode’?
Thread Starter
Joined: Sep 2018
Aviation Qualifications: ATPL
Posts: 402
Likes: 240
From: Seattle
What to do when ATC asks you to switch to ‘ground mode’?
I did a search but didn’t find anything helpful.
Some airports/ATC have asked crew to switch their transponder to ‘ground mode’ after vacating the runway. On the A320 there is no specific switch that directly says ground mode.
What exactly is ATC asking for? Turning off Mode S? In which case selecting the transponder from “ON” to “AUTO” would be the correct selection?
A similar but separate question for the A320 - if you select transponder “ON” but ALT RPTG to “OFF” in your altitude still transmitted?
Thanks,
BD
Some airports/ATC have asked crew to switch their transponder to ‘ground mode’ after vacating the runway. On the A320 there is no specific switch that directly says ground mode.
What exactly is ATC asking for? Turning off Mode S? In which case selecting the transponder from “ON” to “AUTO” would be the correct selection?
A similar but separate question for the A320 - if you select transponder “ON” but ALT RPTG to “OFF” in your altitude still transmitted?
Thanks,
BD
Joined: Jul 2015
Posts: 176
Likes: 230
From: UK
I did a search but didn’t find anything helpful.
Some airports/ATC have asked crew to switch their transponder to ‘ground mode’ after vacating the runway. On the A320 there is no specific switch that directly says ground mode.
What exactly is ATC asking for? Turning off Mode S? In which case selecting the transponder from “ON” to “AUTO” would be the correct selection?
A similar but separate question for the A320 - if you select transponder “ON” but ALT RPTG to “OFF” in your altitude still transmitted?
Thanks,
BD
Some airports/ATC have asked crew to switch their transponder to ‘ground mode’ after vacating the runway. On the A320 there is no specific switch that directly says ground mode.
What exactly is ATC asking for? Turning off Mode S? In which case selecting the transponder from “ON” to “AUTO” would be the correct selection?
A similar but separate question for the A320 - if you select transponder “ON” but ALT RPTG to “OFF” in your altitude still transmitted?
Thanks,
BD
Joined: Mar 2023
Posts: 25
Likes: 8
From: Madrid
Apparently it depends on the aircraft, in our CEOs according to FCOM if you have XPDR auto it will only transmit mode S on the ground but if you keep it ON it will not disable XPDR modes A & C on the ground, with our NEOs responding as you described; but for the OP it is not possible to disable XPDR Mode S without turning the whole XPDR to SBY, and they most likely are requesting you to just put XPDR to AUTO and TCAS to SBY so you still respond to Selective interrogation.
Joined: Jun 2007
Posts: 54
Likes: 3
From: Montreal, Canada
The terminology “ground mode “ is not a typical term in the industry . What ATC wants is for your transponder to be operating with ALT ON + TCAS OFF . Depends on the airplane , you may have the following ( STBY, ALT OFF, ALT ON, TA ONLY , TA/RA ,AUTO ) on your ATC/TCAS control panel, or other device to control the transponder and the TCAS. Just select ALT ON, or AUTO (Auto is typically designed to turn the TCAS on or off based on weight on wheel status ) and you’d be good. ATC needs a working transponder to enable the detection of airplanes on ground at most major airports with surface movement detection such as the ASDE-X which can use different techniques to track airplane including ADS-B OUT which will be working in any position other than STBY.
note : ALL MODE S ARE INHIBITED from replying to a mode s all call, which is what SSR (ATC ) uses to acquire airplanes flying around and put them on the roll call for future individual mode s interrogations.
note : ALL MODE S ARE INHIBITED from replying to a mode s all call, which is what SSR (ATC ) uses to acquire airplanes flying around and put them on the roll call for future individual mode s interrogations.
