# Transponder Mandatory Zone
**URL:** https://forum.safesky.app/t/transponder-mandatory-zone/1104
**Category:** Nederlands
**Created:** [April 28, 2023, 5:30pm UTC](https://forum.safesky.app/t/transponder-mandatory-zone/1104 "2023-04-28T17:30:58Z")
**Posts on this page:** 8
**Page:** 1
### Author:  [@Sunrader](https://forum.safesky.app/u/Sunrader)
#### Post date: [April 28, 2023, 5:30pm UTC](https://forum.safesky.app/t/transponder-mandatory-zone/1104/1 "2023-04-28T17:30:59Z")
Beste lezers, de ontwikkelingen gaan snel. vliegend met een OGN T-beam (softRF) ben ik goed en snel (circa 5 sec Delay) zichtbaar op binnen SafeSky.
Ook mijn maatjes vliegend die met Flarm, FAnet vliegen zijn goed zichtbaar.
Nu even over de zichtbaarheid; als de app actief is tijdens het vliegen werkt deze voor en door alle systemen om me heen.
**Is deze zichtbaarheid voldoende om in een TMZ** (Transponder Mandatory Zone) te vliegen? We hebben namelijk nog wel enkele gebieden om ons heen waar we zouden moeten vliegen met een transponder. zou de actieve App als “transponder” kunnen functioneren?
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### Author:  [@tnowak](https://forum.safesky.app/u/tnowak)
#### Post date: [April 28, 2023, 7:48pm UTC](https://forum.safesky.app/t/transponder-mandatory-zone/1104/2 "2023-04-28T19:48:43Z")
I would say NO, it can’t be used in a TMZ. A TMZ requires your aircraft to respond to radar interrogations. SafeSky can’t do this…
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### Author:  [@rvt](https://forum.safesky.app/u/rvt)
#### Post date: [April 29, 2023, 7:23am UTC](https://forum.safesky.app/t/transponder-mandatory-zone/1104/3 "2023-04-29T07:23:24Z")
Easy Easa says :
_Transponder mandatory zone (TMZ)_
_All flights operating in airspace designated by the competent authority as a transponder mandatory zone (TMZ) shall carry and operate SSR transponders capable of operating on Modes A and C or on Mode S, unless in compliance with alternative provisions prescribed for that particular airspace by the ANSP._
So no, you are not allowed in a TMZ.
To add to that. if you use SoftRF with OGN, you are only visible to other aircraft that also use OGN and/or SafeSky. Not knowing exact statistics but there are not a lot of gliders/GA aircraft that use OGN in NL. If they have any conspicuity at all it would be Flarm. I know one glidefield that uses Flarm and a other one that are on ADSB (don’t know exactly what version…)
If you use the OGN/Safesky setup just assume you are not visible at all to anybody.
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### Author:  [@Sunrader](https://forum.safesky.app/u/Sunrader)
#### Post date: [April 29, 2023, 8:14am UTC](https://forum.safesky.app/t/transponder-mandatory-zone/1104/4 "2023-04-29T08:14:32Z")
Thanx for the first part and the regulation mentioned. helpfull🤙
last sentence however🤔
I think this is not totally the case, since the possibility of using the app and seeing and hearing other planes approach within my preset boundary. works fine within GA at our positioning in the Netherlands [Safesky](https://youtu.be/obInKnT28Qo)
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### Author:  [@rvt](https://forum.safesky.app/u/rvt)
#### Post date: [April 29, 2023, 11:15am UTC](https://forum.safesky.app/t/transponder-mandatory-zone/1104/5 "2023-04-29T11:15:57Z")
I was reading you last sentence like this : _If other traffic will see **you**._
I was reading it because you mentioned flying in a TMZ. Flying in a TMZ means that ATC will see you because of ADSB + Interrogation on MODE-s (because Transponder is Mandatory).
When you fly without ADSB, ATC will only see a bleep.
Hope that clarifies how I was reading your question.
Edit: Clarification based on Pascal’s remark.
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### Author:  [@Sunrader](https://forum.safesky.app/u/Sunrader)
#### Post date: [April 29, 2023, 2:57pm UTC](https://forum.safesky.app/t/transponder-mandatory-zone/1104/6 "2023-04-29T14:57:27Z")
Thank you for the clear explanation 👍 I understand now the way communication has to work in TMZ
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### Author:  [@Pascal](https://forum.safesky.app/u/Pascal)
#### Post date: [April 30, 2023, 9:56am UTC](https://forum.safesky.app/t/transponder-mandatory-zone/1104/7 "2023-04-30T09:56:59Z")
Sorry but Your sentence shall be corrected:
yes the ADS-B alllows to provide additional data as aircraft position and velocity, BUT with mode S transponder without ADS-B allows the ATC radar to display your 4 digits assigned transponder code, your aircraft registerd ident, and the altitude of your aircraft, then not only a radar “bleep”…
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### Author:  [@Mariko](https://forum.safesky.app/u/Mariko)
#### Post date: [May 25, 2023, 4:05pm UTC](https://forum.safesky.app/t/transponder-mandatory-zone/1104/8 "2023-05-25T16:05:01Z")
All the italian airspace is a TMZ for GA and Advanced Ultralight Machines. But a mode A,C trasponder is enough to accomply that rule.