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Peter Armstrong
ZSE Controller
ZSE Controller
Joined:Fri Dec 11, 2015 8:05 am

Post by Peter Armstrong » Mon Jan 08, 2018 2:27 am


Whilst controlling recently, a Student OBS asked me a question – “what happens to a VFR flight after released by TWR, assuming APP is on line/off line”?

Not being a mentor/INS I feel that question should be answered by those qualified to do so.

I presume that there may be multiple choices in this answer – notwithstanding the Airspace involved!

Happy controlling/flying :beer:
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Frank Miller
ZSE Training Administrator
ZSE Training Administrator
Joined:Mon Oct 27, 2014 4:51 pm


Post by Frank Miller » Mon Jan 08, 2018 4:33 pm

Assuming no flight following, here is what a VFR pilot would do:

1. Class D. Tower approves a frequency change on leaving the Delta. Pilot switches to UNICOM, squawks VFR (which should be the case anyway in Delta airspace absent a local practice of assigning a squawk code for some reason) and proceeds on course.

2. Class Charlie. Tower approves a frequency change on leaving the Charlie at the surface level ring (i.e. VFR pilot did not climb up into the Charlie that is controlled by App/Dep). I’ve heard this referred to as a “punch out”. Tower instructs pilot to squawk VFR (which he might be doing or might not—-e.g. at Portland we assign squawk codes) and remain clear of the Charlie. Pilot switches to UNICOM, stays below the upper tier of the Charlie airspace, and proceeds on course.

If the VFR pilot wishes to climb up out of the Tower’s airspace but still in the Charlie (before leaving laterally), then Tower hands off to App/Dep, and that controller radar identifies the aircraft (assigning a squawk code if one hadn’t already been assigned) and stays with him until exiting the Charlie. At that point App/Dep terminates radar services, approves the frequency change and instructs the pilot to squawk VFR and remain clear of the Charlie. Pilot switches to UNICOM and proceeds on course.

3. Class Bravo. Same as Charlie except aircraft will definately have a squawk code and not need be instructed to remain clear of the Bravo (though often that is said anyway just so it is absolutely clear the previous Bravo clearance no longer applies to re-entry).

For any of these where the VFR pilot has asked for flight following services, the pilot will keep his squawk code and be handed off to App/Dep in all cases for that service (just like an IFR departure).

In VATSIM it is also possible that App/Dep/Ctr will be offline so no services are available. In this case, any handoff that would have been to App/Dep will simply be a “no further ATC available, monitor Unicom”. You would not need to have the pilot squawk VFR since the “simulation” remains that they are in the radar environment, just on UNICOM per VATSIM policy.

Two additional special situations:

1. I have observed Sea-Tac tower controllers hand off VFR pilots leaving the Bravo airspace below 2000 or so when crossing the shoreline west and heading over Puget Sound. This is incorrect as the Sea-Tac class Delta airspace actually extends further out, to Vashon Island even though the Bravo at that altitude only extends to the shoreline. Similarly to the east heading toward Lake Youngs. Tower can tell the VFR pilot he is clear of the Bravo but should not approve the frequency change until clear of the Delta as until then the pilot needs to be in two-way radio comms with Tower.

2. When departing Sea-Tac to the north, a VFR pilot may leave the Sea-Tac tower airspace below 2,500 but transition the contiguous Delta airspace for either Boeing Field or Renton. In these instances there should be a handoff to whichever controller is providing tower services for that airport (often Seattle Approach) for two reasons: (a) the VFR pilot may still be in the Sea-Tac Bravo, and (b) the VFR pilot is at the very least in KBFI/KRNT Delta airspace. A similar approach should be take for KPDX and KTTD, as well as KGEG and KSFF/KSKA.

Maybe others have other views or additional tips.

Hope that helps!


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