In article ,
Newps wrote:

Hamish Reid wrote:

Since it was me you originally responded to, let's review the sequence
of events: I was on a pre-filed IFR clearance to Stockton (KSCK), went
missed on the ILS, went back to NorCal and cancelled IFR, requesting
multiple practice approaches. I got the standard "Maintain VFR..." at
that point, then did three practice approaches with NorCal: two at
Stockton, then the one at Tracy (KTCY) that caused the issue (Tracy's
VOR/DME GPS-A approach starts close to Stockton, so it's a natural on
currency flights like this). When I reported back on the missed at Tracy
and requested flight following back to Hayward (KHWD) I was asked to
cancel IFR. That made absolutely no sense at that point, since I hadn't
been on an IFR clearance since going missed on the ILS at Stockton some
30 or 40 minutes earlier. No mode C changes were made, which is (IIRC)
SOP with NorCal at Stockton.

OK, I can see what maybe happened here. You were IFR then went VFR.
When you're IFR you will be on a code that will show low altitude
warnings, this is not necessary when VFR. Your data block on the radar
scope while you were IFR is standard. One quick look at it and
everybody knows that you are IFR. Facilities can use any type of data
block for VFR aircraft. An IFR data block looks like this:

N12345
070 15
/
/
/
N
A way to show an aircraft is VFR is to put a "V" after the 15.
Here at BIL we will take the same airplane when he's VFR and it will
look like this:

TC345
070 15
/
/
/
N

So there's no way to mistake whether or not an aircraft is IFR or VFR.
The TC stands for twin Cessna. We have abbreviations for a lot of
different types.
So it's possible that after you changed to VFR the controller simply
forgot you were VFR, maybe forgot to put the letter in the data block.
This is why our system here at BIL is vastly superior to using full data
blocks.

Thanks -- a clear explanation from a controller's point of view. Seems
pretty damn plausible to me, especially since NorCal usually gets this
sort of thing right, and the controller who originally fielded my IFR
cancellation seemed in no doubt that I was VFR from that point on. If he
just forgot to update the data block, oh well...

Hamish