Primarily for general aviation discussion, but other aviation topics are also welcome.
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By 2Donkeys
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#1859280
An IFR Flight in airways on an airways squawk gets close to its VFR-only destination and is dropped out of controlled airspace with a phrase along the lines of

Cleared to leave controlled airspace by descent. Freecall Anytown radio on 123.455 goodbye.

Under these circumstances, what is the expected transponder behaviour?

- Leave airways squawk on until outside controlled airspace and then set 7000

- The same but set 2000

- Leave the airways squawk on until landing.

- Something else.


I ask out of genuine curiosity since controllers almost never refer to the transponder setting under these circumstances in my experience.
By johnm
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#1859285
I'd squawk 2000 if continuing IFR outside controlled airspace or 7000 if changing to VFR, but it's an interesting question as to whether one should hold onto a squawk from a unit you are no longer talking to, Radar should discourage them reallocating it and ending up with 2 versions of the same squawk.
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By GrahamB
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#1859289
johnm wrote:I'd squawk 2000 if continuing IFR outside controlled airspace or 7000 if changing to VFR, but it's an interesting question as to whether one should hold onto a squawk from a unit you are no longer talking to, Radar should discourage them reallocating it and ending up with 2 versions of the same squawk.

AFAIU, on an airways flight the squawk is allocated to you by Eurocontrol, not an ATC unit, for the duration and remains with that FPL until closed (either explicity or implicitly).

When I've conducted an IFR 'airways' flight where I've dropped out of CAS and gone back in, if I've had to change to something else when outside, on re-entry it's my experience to be given the squawk I started with.

In the case where you're leaving by descent when close to destination, who's to say you may not need to re-enter in order to divert to alternate?
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#1859298
All answers are pretty valid when it’s VMC OCAS

If it’s IMC, I would keep my airways squawk as there is a high risk of going back in CAS again with clearance to my alternate, the I-FPL should be alive in Brussels computer with your TXP code until you land?

Same story in other countries, they ask for “cancel IFR, set 7000” on leaving CAS by descent or descending bellow MVA to somewhere VFR (even when you are 5000ft above MSA), if you do that you have to be bloody sure the destination is not IMC or you are locked out of the system forever, if it’s VMC, the point is moot…
Last edited by Ibra on Sat Jul 17, 2021 7:00 pm, edited 7 times in total.
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By 2Donkeys
FLYER Club Member  FLYER Club Member
#1859299
Interesting to see the diversity of answers from a number of people I know to be instrument rated pilots. If nothing else, it underlines my sense that this is not a particularly clearly understood topic.

My own practice, has been to hold onto the squawk until landing unless otherwise instructed. Would be interesting to hear a view from ATC.
#1859302
Hi 2Ds

I think that once one has left 'airways' ATC has the prerogative to re-issue the ORCAM code (or whatever it might be called these days) and terminate any code/callsign conversion (if applied). ANSPs operating Class E and Class G airspace are going to be more interested in whether your SSR response is IFR or VFR, and would expect a conspicuity squawk, and not necessarily be bothered about your historic flight ID whilst on airways. I have to say I am a little surprised to hear that such lax SSR code management has not apparently improved, and that you have not been instructed to 'squawk conspicuity' on leaving airways. Many on here would, yet again, tell me that I do not know what I am talking about, and that I am living in the past, so I would endeavour to seek out a definitive procedure in a definitive document instead. However I too am distracted by refreshment to be bothered right now....
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#1859305
Depends on how much time you have until destination, if you (ever) call London Info in the meantime (they are helpful to get the last weather) they will ask you 1177C, will you do it :wink: ?

It’s less trivial, assuming hardcore IMC and you just left CAS by descent with no handovers, what about calling out of blue a VFR destination with own conspicuity squawks (Redhill) or IFR destinations not connected to airways (Cambridge) or procedural (Lydd), they may give you new TXP, how do you handle it with TXP ID from EC?

In VMC OCAS not talking to anyone VFR/IFR, one is still allowed to put lot of choices on their TXP without asking ATC…
#1859313
Naughty/lazy controller should really tell you to squawk conspicuity.

So if they don’t, keep the squawk and fly the next 100miles or so with everyone saying “why is he squawking that”

And most will damn the lazy ATCO. Until someone reallocates the squawk and you become BAW001 or sumpfink.

Gash work really. Unless leaving Farnborough for the Bushe or dropping out of the TMA for Stapleford etc and then to be fair, you will be down and no longer radar tracked within 5 mins.
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By James Chan
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#1859318
I'd continue with the squawk as it's allocated to me for the duration of the flight, unless asked to change it by another unit I may work.


Same here. I think the problem with self-setting any other code is that it can trigger some undesired effects at ATC.
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By PeteSpencer
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#1859320
I've usually got
' \Basic service outside controlled airspace ' when they drop me/I announce I want to continue VFR.

They usually hang onto me for a while OCAS with same squawk then when they dump me its
'Squawk conspicuity, freecall xxx.xxx'
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By JonathanB
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#1859329
It often depends on the unit you’re going to. E.g leaving CAS for Gloucester but working Brize in between then you’d keep the airways squawk. Being transferred directly to Gloucester then you should be asked to squawk conspicuity. Leaving for Exeter or Oxford then you just stay on airways squawk. Leaving for Newquay then you’ll be given a Newquay squawk. If you’re free calling anywhere then it should be a “Squawk conspicuity”.