Transponder code switching

"Mike Beede" wrote in message
...

The only time it really makes a difference is if you accidentally
switch it to the 7500+ neighborhood. A good rule of thumb is to roll in
the first number (which at least in the Minneapolis area is never 7) and
then do the rest.

Do people get 7xxx codes elsewhere in the United States?

FWIW, in most of the rest of the world the conspicuity code ("VFR", in
effect) is 7000 rather than 1200. There's rather more room for error of the
sort you're thinking of.

Moreover, when the question is asked on forums in Europe, controllers
suggest that *any* random code can cause problems because if you happen upon
one that has been assigned to IFR traffic, the radar system picks up the
squawk and labels you as that airways flight, which is time-consuming for
ATC to fix. Is there no similar issue in the US because of different ATC
systems? The issue is less about momentary selection as you pass through the
digits and more about cockpit distraction meaning that the wrong code gets
left on for a while.

Julian Scarfe

"Julian Scarfe" wrote in message ...
"Mike Beede" wrote in message
...

The only time it really makes a difference is if you accidentally
switch it to the 7500+ neighborhood. A good rule of thumb is to roll in
the first number (which at least in the Minneapolis area is never 7) and
then do the rest.

Do people get 7xxx codes elsewhere in the United States?

FWIW, in most of the rest of the world the conspicuity code ("VFR", in
effect) is 7000 rather than 1200. There's rather more room for error of the
sort you're thinking of.

And people do get 7XXX codes in the US, just not 75XX, 76XX, 77XX.

Teacherjh,

AIM or no AIM, I'd put it to standby while changing the squawk.


Yeah, right. And while we're at it, why not ignore runway markings,
visibility requirements and whatever else is in the AIM, too? Jeeze!

--
Thomas Borchert (EDDH)

And while we're at it, why not ignore runway markings,
visibility requirements and whatever else is in the AIM, too? Jeeze!


AIM is not gospel, and although it represents distilled (good) judgement, it
should not =replace= judgement.

Jose

--
(for Email, make the obvious changes in my address)

Teacherjh,

AIM is not gospel, and although it represents distilled (good) judgement, it
should not =replace= judgement.


Of course not. But there was no judgement in your post.

--
Thomas Borchert (EDDH)

But there was no judgement in your post.

Sure there was. I made the judgement that it was better for me to briefly not
reply to a ping than to reply inappropriately as I was switching numbers.

Jose

--
(for Email, make the obvious changes in my address)

Teacherjh wrote:

But there was no judgement in your post.


Sure there was. I made the judgement that it was better for me to briefly not
reply to a ping than to reply inappropriately as I was switching numbers.

It takes at least two sweeps and sometimes as many as 5 sweeps before
the radar will tag you up on a code you're squawking.

Newps writes:

It takes at least two sweeps and sometimes as many as 5 sweeps before
the radar will tag you up on a code you're squawking.

Is that true of all radar equipment? I've sometimes been assigned a
new squawk code then heard "radar contact" within a couple of seconds
(usually, though, it's more like 20-30 seconds, which would agree with
what Newps writes).


All the best,


David

Teacherjh wrote:

AIM or no AIM, I'd put it to standby while changing the squawk. You're not
supposed to squawk an incorrect code either, and if you're not on standby,
that's what you're doing while changing.

And just how glacially do you change codes? Center radar antennas
rotate at 12 seconds per sweep, terminal radars at 6 seconds per sweep.
When you are changeing codes the target on the scope coasts for
several sweeps until your new code stays the same for about three sweeps.



I suspect it doesn't make much difference as it's over in a moment.

Exactly.