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When am I allowed to change my transponder code to 1200?

Is it after clearing the boundary of regulatory airspace (ie. airspace requiring radio contact and an operating transponder)?

Ryan Mortensen
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Konrad Reiher
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    Why are you so desperate to change to 1200? When squawking a discreet code (e.g. one given by ATC), they will keep an eye on you on the radar - making sure you do not collide with other traffic or enter restricted airspaces. When squawking 1200, they lose this ability, and you essentially lose a very strong safety net that could prevent dangerous situations. – 60levelchange Jun 08 '16 at 07:45
  • @J.Hougaard changing to 1200 and dropping radar service doesn't make you invisible to ATC. One great reason to drop ATC is for area maneuvers. It can be annoying to have to get permission every time you want to turn. So, for lessons; that's one reason. – Ryan Mortensen Jun 08 '16 at 07:56
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    @RyanMortensen Sure, you are not invisible. But you are anonymous. Even if ATC can see two 1200 tracks on a collision course, there is not much they can do about it, since they do not know who it is. As for "getting permission every time you want to turn", I don't see any correlation between squawking a discreet code and being under ATC control. If you are in uncontrolled airspace, you can "do as you want" - no matter what your transponder code is. – 60levelchange Jun 08 '16 at 08:01
  • @RyanMortensen You can request/advise (depending on previous instructions) to “maneuver” while staying on VFRFF. This frees you from needing to request/advise every turn, climb/descent, etc. while still getting traffic and being in contact if ATC needs to move or restrict you for some reason. They will often assume this if you’re headed into a known practice area. – StephenS Feb 13 '21 at 16:00
  • @StephenS I don't expect a VFR pilot to request permission for altitude or heading changes unless they were explicitly instructed to fly a specific heading or at a specific altitude. Aside from that case, you're VFR, you do what you want. If you're in a congested area an advisory might be appreciated prior to an altitude change but it isn't required. – randomhead Dec 05 '21 at 21:16
  • @randomhead I’ve been on VFRFF before, no restrictions, and within a few seconds of making an unexpected turn or climb/descent, the controller called me to ask what I was doing—and maybe make sure I was okay. So, I always try to advise (not request) first. – StephenS Dec 05 '21 at 22:12

2 Answers2

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ATC will tell you something like, "N1234R radar service terminated. Squawk VFR. Frequency change approved; good day" which you will repeat back as an instruction.

You do not change from the assigned transponder code until instructed.

If you're in a hurry to get away from ATC, you may request to terminate radar service as soon as you are out of their regulatory airspace.

Ryan Mortensen
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-4

Normally, as a courtesy, you terminate radar service by notifying ATC in a handshake as in Mortensen's answer. In most cases this never happens, because as soon as you leave their zone ATC will terminate service unilaterally--you don't have to ask for it.

If you are flying under IFR rules in any airspace except G, you must have a clearance and be using the code currently assigned to you under the clearance.

If you are flying VFR, you normally use code 1200. You can change to 1200 whenever you want, but if you previously had a clearance, you will immediately lose your clearance when you switch to 1200.

Therefore, the general principle is that you can switch to 1200 whenever you are flying VFR and do not require a clearance to be where you are. In class B, C, and D you are required to be in "voice contact" with ATC, which could be construed to require a handoff. In class E you are only required to be in voice contact if you are in the vicinity of a towered airport, in which case you have to be in voice contact with the tower (not ATC). So, basically what this means is that if you are in G or E (not near an airport) you can go to 1200 whenever you want. In B, C, D you should always do signoffs ("Cessna 5678 Golf terminating radar service"). If you are in an area that requires a clearance, you must get permission to terminate radar service.

So, your own statement is basically correct: once you leave a radio-contact required area, you are free to go VFR. Note that if you abandon a flight plan and go VFR without notifying ATC, even if you are in a radio-free zone, they can get miffed about that because it messes up their rack, so it is always a good practice to explicitly terminate your service/flight plan before switching to VFR and going numberless.

Example: You are flying VFR through a restricted military operating area and have a clearance to do so. You must stay on code as long as you are in the restricted area, because you require a clearance to be there.

Tyler Durden
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  • @RyanMortensen State the reg, paragraph number, that requires a pilot flying VFR to get ATC permission to switch from an assigned code to 1200. – Tyler Durden Jun 08 '16 at 13:35
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    It may not be your intention, but your wording suggests that pilots can just switch from a squawk assigned by ATC to 1200 if they feel like it, which isn't the case (see 14 CFR 91.123(b)). And you might want to modify your last example: VFR flights don't need a clearance to enter a MOA. – Pondlife Jun 08 '16 at 14:20
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    @RyanMortensen Where is it stated that you cannot fly IFR in class G airspace? If true, it must be a rule specific to the FAA. IFR in class G happens daily at my local airport. – 60levelchange Jun 08 '16 at 14:24
  • @J.Hougaard this may be a great "primary question" for someone to post. I left the possibility that I am mistaken open as a possibility up there ^^. Turns out I was wrong indeed; it is legal. However, the research I just did revealed a general consensus by those discussing it that was, "it is legal until you get violated by 91.13 for careless or reckless operation." +1 for calling that out. – Ryan Mortensen Jun 08 '16 at 15:09
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    @TylerDurden Pondlife is right. ATC providing you with a squawk code and telling you to use it is an instruction, and it has no void time. You need to tell them you want to drop service or wait for them to tell you that they are dropping service. – Ryan Mortensen Jun 08 '16 at 15:13
  • @Pondlife I said a RESTRICTED military operating area. – Tyler Durden Jun 08 '16 at 15:30
  • There's no such thing as a "restricted MOA"; there are restricted areas, and there are MOAs, and the rules are different for each one. See section 4 of the AIM. – Pondlife Jun 08 '16 at 15:37
  • @Pondlife I meant a restricted area for military use, which I called an "MOA" sorry for the confusion. As far as terminating radar service, a pilot can terminate it at any time by switching to 1200. The CFR you cite is only when deviating from a required clearance and it is the pilot's intention to maintain that clearance. Radar service is just that: a SERVICE, not a requirement. – Tyler Durden Jun 08 '16 at 15:45
  • @TylerDurden It is a service in which you receive ATC instructions. It isn't about it being a voluntary service, it's about the agreement with ATC to follow their instructions. See: When has a pilot legally accepted an ATC clearance or instruction?. Being in an area where ATC contact isn't required does not give a pilot the authority to go AWOL after agreeing to use a certain transponder code. A new agreement is then required for 1200. – Ryan Mortensen Jun 08 '16 at 16:22
  • @RyanMortensen That is not true. It's called a service because that is what it is. I have already read Pondlife's opinions and do not think they are legally supported in any way. Just as one example, if I am in Class E I can turn off my radio and I do not have to even listen to ATC at all if I don't want to. There is no legal requirement to talk to ATC if you are out of a voice contact zone. – Tyler Durden Jun 08 '16 at 17:45
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    @TylerDurden once again, it isn't about a requirement to talk to ATC where you are. It is about following the ATC instructions that you have already accepted. Also, once again, 14 CFR 91.123(b) "(b) Except in an emergency, no person may operate an aircraft contrary to an ATC instruction in an area in which air traffic control is exercised." Squawking a specific code is an instruction. ATC control is exercised in class E airspace. – Ryan Mortensen Jun 08 '16 at 17:50
  • @RyanMortensen Radar service is not an "instruction". A pilot may drop radar service whenever they want, except in Class A or other specially restricted airspace. – Tyler Durden Feb 14 '21 at 08:39