transponder codes

"Guy Elden Jr." wrote in message
...

On the way back up, as we were departing Roanoke, the tower controller and
then departure controller gave me some weird transponder codes. I was
wondering if anybody here could enlighten me as to what may have been
happening. First, I was told to squawk 7000 (this was an IFR trip, btw).


The 7000 code block is used by Washington ARTCC for departures that will be
exiting their airspace. But only discrete codes would be assigned from that
block; 7001, 7002, etc. If you're departing a non-ARTS facility, which I
assume ROA is not, the computer assigned code will time-out after one hour
and revert to the non-discrete base code, i.e., a 7032 code would become
7000. If the aircraft does depart within the next hour a new discrete code
will be generated when the departure is entered in the computer.



After liftoff, tower hadn't handed me off to departure like I expected, so
I
asked if I should change frequencies. He responded that he was waiting for
another transponder code for me to try before handing me off... new one
was 1234.


Codes 1201-1272, unless otherwise allocated, are used for DVFR aircraft.



At this point I began to suspect I was about to be a victim of some
cruel ATC joke, and I knew I was when he handed me off to departure, who
assigned me yet another new code... 0123.


Codes 0100-0477 are assigned for terminal operations, radar services to VFR
aircraft and local IFR operations not entered in the flight data processing
computer.