ATC did ask her to stop ModeC, they did not know how to do it, so they just
turned it off.
Good thing they were not inside the Class B Mode C Veil or need to
transition it on the return flight.

BT

"Robert M. Gary" wrote in message
...
On Nov 25, 10:38 am, " wrote:

Reason for cancelling flight following (my rational) was that an
improperly mode C reporting Xponder was worse then no Xponder.
Doesn't do Center any good to see us at an altitude we were not at.
Since we were in a busy sector of KJAN, troubleshooting while with
them wasn't a viable option. Since we didn't know how to turn off
Mode C, I figured shut the thing down.

You probably had no choice. ATC doesn't seem to mind you not having
mode C (I've had to go out over Los Angeles and was still given my IFR
clearance) but they really don't want incorrect readings. My guess is
that if you couldn't turn off the mode C ATC would ask you to turn off
the transponder and therefore give up the FF. Perhaps if you were in
the middle of nowhere it would be different but when you have lots of
ATC personell working the same area at different altitudes I don't
think they want to spend their day talking to each one explaining what
is going on everytime you change controllers.

-Robert