I was piloting outside of Class B airspace in an area well known for being difficult from which to contact ATC via radio because of mountainous terrain. When I did get cleared into Class B, I was only about a mile outside of Class B airspace. Immediately, another controller took over (different gender / same frequency), revoked the clearance, and said to stay clear of Class B and scolded me for only being one mile outside of Class B. (I complied with that request, never entering Class B – so there was no violation.)

Question: Can you legally be “uncleared” into Class B after receiving a clearance into Class B? Could you speculate on what may have happened?

  • $\begingroup$ Unless you are in an emergency, you are required to comply with all ATC instructions, so yes, a clearance can be revoked. Just like a landing clearance or crossing clearance. The controller shouldn't have scolded you though, you were clear of the airspace, unless you were coming in at a fast rate. Ideally you'd like to get clearance quite a bit before that. I like to contact Class C at least 20 miles out, and for Class B I'd get flight following if possible as I left my origin. $\endgroup$ – Ron Beyer Aug 22 '16 at 3:03
  • $\begingroup$ Sure, a clearance can be changed or even revoked. It happens all the time. The traffic situation may change, equipment could fail, an emergency could appear, etc. Air traffic control is extremely dynamic - the work of the controller can change 100% in as little as 5 minutes. $\endgroup$ – J. Hougaard Aug 22 '16 at 4:22
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    $\begingroup$ I'd listen to the conversation on liveatc.net and make sure that it really did happen as you recall. If it did, I'd file an ASRS report: as you described it, it seems that the handover from one controller to another wasn't done well. If the second controller "scolded" you then s/he was presumably unaware of the previous clearance issued, and that shouldn't be the case. $\endgroup$ – Pondlife Aug 22 '16 at 13:33
  • $\begingroup$ @Pondlife It doesn't sound like a frequency change to me. More likely, a supervisor cut in after the other controller already gave the clearance because they weren't comfortable with the potential situation. I hear this happen every once in a while. $\endgroup$ – Lnafziger Aug 24 '16 at 1:38
  • $\begingroup$ @Lnafziger That's an interesting idea, I didn't think of that. But then why would the supervisor scold the pilot if the mistake was on the ATC side? I actually understood it was a controller change, not a frequency change. $\endgroup$ – Pondlife Aug 24 '16 at 13:09

Every clearance can be cancelled or revoked, irrespective of the type of clearance.


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