Transponder code switching

[Ken Pruchnick]

What is the proper way to switch transponder codes? The way I have
been taught is to put the transponder in stand by, switch to the new
code. Then turn it to mode C
I had an instructor tell me to just change it to the new code without
turning it to stand by first.
Like to hear from controllers as to what they prefer.

[Bob Gardner]

I'm not a controller, but I do have a copy of the AIM that says in capital
letters (4-1-18) that you are supposed to have it on at all times, and in
4-1-19 regarding code changes, does not tell you to turn it off.

So the second instructor was right.

Bob Gardner

"Ken Pruchnick" > wrote in message
om...
> What is the proper way to switch transponder codes? The way I have
> been taught is to put the transponder in stand by, switch to the new
> code. Then turn it to mode C
> I had an instructor tell me to just change it to the new code without
> turning it to stand by first.
> Like to hear from controllers as to what they prefer.

[Mark Kolber]

On 6 Oct 2003 13:41:42 -0700, (Ken Pruchnick) wrote:

> Like to hear from controllers as to what they prefer.

We heard from a controller when this topic came up on another forum.
The word was, do not squawk standby unless they ask you to.



Mark Kolber
APA/Denver, Colorado
www.midlifeflight.com
======================
email? Remove ".no.spam"

[Teacherjh]

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.

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

Jose

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

[Mike Beede]

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

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?

Regards,

Mike

[Sven]

"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?

Not sure about assigning 7xxx codes...

I found a list of transponder codes besides the 1200/7500/7600/7700:

1255 is for VFR aircraft engaged in fighting forest fires
1277 is for VFR aircraft engaged in search & rescue operations
4000 is reserved for VFR military aircraft on training missions
4400-4477 are reserved for aircraft operating above FL600
At no time should 7777 be used, as this is for military interception
procedures
(Source: 2003-2004 Iowa Airport Directory page 135)

Are there others?

[John Harper]

Would be kind of cute to "accidentally" select 44xx and
see what altitude they assign...

"Sven" > wrote in message
news:Ewqgb.701786$uu5.115368@sccrnsc04...
> "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?
>
> Not sure about assigning 7xxx codes...
>
> I found a list of transponder codes besides the 1200/7500/7600/7700:
>
> 1255 is for VFR aircraft engaged in fighting forest fires
> 1277 is for VFR aircraft engaged in search & rescue operations
> 4000 is reserved for VFR military aircraft on training missions
> 4400-4477 are reserved for aircraft operating above FL600
> At no time should 7777 be used, as this is for military interception
> procedures
> (Source: 2003-2004 Iowa Airport Directory page 135)
>
> Are there others?
>
>

[Greg Burkhart]

"John Harper" > wrote in message
news:1065499936.802114@sj-nntpcache-3...
> Would be kind of cute to "accidentally" select 44xx and
> see what altitude they assign...


I doubt that they would confuse someone flying at FL065 with someone at
FL650.

The saying you won't hear: "Cessna Skyhawk, climb to FL650, Squawk 4444..."

[David Megginson]

"Sven" > writes:

> I found a list of transponder codes besides the 1200/7500/7600/7700:
>
> 1255 is for VFR aircraft engaged in fighting forest fires
> 1277 is for VFR aircraft engaged in search & rescue operations
> 4000 is reserved for VFR military aircraft on training missions
> 4400-4477 are reserved for aircraft operating above FL600
> At no time should 7777 be used, as this is for military interception
> procedures
> (Source: 2003-2004 Iowa Airport Directory page 135)
>
> Are there others?

Here are some Canadian default codes (uncontrolled, or no transponder
code yet assigned):

1400 VFR above 12,500 ft
1000 IFR in low-level airspace
2000 IFR in high-level airspace


All the best,


David

[Thomas Borchert]

Ken,

leave it on while switching. The AIM says so.

--
Thomas Borchert (EDDH)

[Thomas Borchert]

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)

[Newps]

Ken Pruchnick wrote:
> What is the proper way to switch transponder codes? The way I have
> been taught is to put the transponder in stand by, switch to the new
> code. Then turn it to mode C
> I had an instructor tell me to just change it to the new code without
> turning it to stand by first.
> Like to hear from controllers as to what they prefer.

Just change the numbers, it doesn't matter how you do it. On my plane
the transponder never goes into standby, there's no good reason to ever
turn your transponder off of the ALT position if it is working properly
and you have an avionics master.

[Newps]

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.

[Newps]

And there are other codes that cause alarms that are secret, so don't
worry about it and just switch the numbers.

Sven wrote:

> "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?
>
>
> Not sure about assigning 7xxx codes...
>
> I found a list of transponder codes besides the 1200/7500/7600/7700:
>
> 1255 is for VFR aircraft engaged in fighting forest fires
> 1277 is for VFR aircraft engaged in search & rescue operations
> 4000 is reserved for VFR military aircraft on training missions
> 4400-4477 are reserved for aircraft operating above FL600
> At no time should 7777 be used, as this is for military interception
> procedures
> (Source: 2003-2004 Iowa Airport Directory page 135)
>
> Are there others?
>
>

[Chip Jones]

"Newps" > wrote in message
news:3Gzgb.514047$Oz4.370169@rwcrnsc54...
> And there are other codes that cause alarms that are secret, so don't
> worry about it and just switch the numbers.

Awww Newps, now we have to kill you...

Chip, ZTL

[Steven P. McNicoll]

"Ray Andraka" > wrote in message
...
>
> I put mine in the alt position after clearing the runway. That way, next
> time I turn on the avionics I'm not squawking an IFR code that might be in
> use.
>

I assume you meant to write "stby" in place of "alt".

[Ray Andraka]

I put mine in the alt position after clearing the runway. That way, next
time I turn on the avionics I'm not squawking an IFR code that might be in
use.

Newps wrote:

> Ken Pruchnick wrote:
> > What is the proper way to switch transponder codes? The way I have
> > been taught is to put the transponder in stand by, switch to the new
> > code. Then turn it to mode C
> > I had an instructor tell me to just change it to the new code without
> > turning it to stand by first.
> > Like to hear from controllers as to what they prefer.
>
> Just change the numbers, it doesn't matter how you do it. On my plane
> the transponder never goes into standby, there's no good reason to ever
> turn your transponder off of the ALT position if it is working properly
> and you have an avionics master.

--
--Ray Andraka, P.E.
President, the Andraka Consulting Group, Inc.
401/884-7930 Fax 401/884-7950
email
http://www.andraka.com

"They that give up essential liberty to obtain a little
temporary safety deserve neither liberty nor safety."
-Benjamin Franklin, 1759

[Montblack]

("Chip Jones" wrote)
> > And there are other codes that cause alarms that are secret, so don't
> > worry about it and just switch the numbers.
>
> Awww Newps, now we have to kill you...


Newps, quick, hide in the FAR's!!!


Just saw this play (again) this past week. One of my favorites.

From A Man for All Seasons, by Robert Bolt

Setting - Sir Thomas More has declined to employ Richard Rich, who has just
left the room.

Wife: Arrest him!
More: For what?
Wife: He's dangerous!
Roper: For all we know he's a spy!

Daughter: Father, that man's bad!
More: There's no law against that!
Roper: There is, God's law!
More: Then let God arrest him!

Wife: While you talk he's gone!
More: And go he should, if he were the Devil himself, until he broke the
law!

Roper: So, now you give the Devil the benefit of law!
More: Yes! What would you do? Cut a great road through the law to get after
the Devil?
Roper: Yes, I'd cut down every law in England to do that!

More: Oh? And when the last law was down, and the Devil turned 'round on
you, where would you hide, Roper, the laws all being flat?

This country is planted thick with laws, from coast to coast, Man's laws,
not God's! And if you cut them down (and you're just the man to do it!), do
you really think you could stand upright in the winds that would blow then?

Yes, I'd give the Devil benefit of law, for my own safety's sake!

--
Montblack

[Teacherjh]

>>
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)

[Tom S.]

"Montblack" > wrote in message
...
> ("Chip Jones" wrote)
> > > And there are other codes that cause alarms that are secret, so don't
> > > worry about it and just switch the numbers.
> >
> > Awww Newps, now we have to kill you...
>
>
> Newps, quick, hide in the FAR's!!!
>
>
> Just saw this play (again) this past week. One of my favorites.
>
> From A Man for All Seasons, by Robert Bolt
>
> Setting - Sir Thomas More has declined to employ Richard Rich, who has
just
> left the room.
>
> Wife: Arrest him!
> More: For what?
> Wife: He's dangerous!
> Roper: For all we know he's a spy!
>
> Daughter: Father, that man's bad!
> More: There's no law against that!
> Roper: There is, God's law!
> More: Then let God arrest him!
>
> Wife: While you talk he's gone!
> More: And go he should, if he were the Devil himself, until he broke the
> law!
>
> Roper: So, now you give the Devil the benefit of law!
> More: Yes! What would you do? Cut a great road through the law to get
after
> the Devil?
> Roper: Yes, I'd cut down every law in England to do that!
>
> More: Oh? And when the last law was down, and the Devil turned 'round on
> you, where would you hide, Roper, the laws all being flat?
>
> This country is planted thick with laws, from coast to coast, Man's laws,
> not God's! And if you cut them down (and you're just the man to do it!),
do
> you really think you could stand upright in the winds that would blow
then?
>
> Yes, I'd give the Devil benefit of law, for my own safety's sake!
>

You definitely need less caffeine. :~)

[Thomas Borchert]

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)

[Ray Andraka]

No, I only squawk on the ground. That way no one knows where I am ;-).

Guess it is old age catching up with me, huh?

"Steven P. McNicoll" wrote:

> "Ray Andraka" > wrote in message
> ...
> >
> > I put mine in the alt position after clearing the runway. That way, next
> > time I turn on the avionics I'm not squawking an IFR code that might be in
> > use.
> >
>
> I assume you meant to write "stby" in place of "alt".

--
--Ray Andraka, P.E.
President, the Andraka Consulting Group, Inc.
401/884-7930 Fax 401/884-7950
email
http://www.andraka.com

"They that give up essential liberty to obtain a little
temporary safety deserve neither liberty nor safety."
-Benjamin Franklin, 1759

[Teacherjh]

>> 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)

[Newps]

Ray Andraka wrote:
> I put mine in the alt position after clearing the runway. That way, next
> time I turn on the avionics I'm not squawking an IFR code that might be in
> use.


Doesn't matter as the software in the radar is calibrated so as not to
display a code on the airport. We have ours set so no transponder
returns show until you get more than 1/2 mile away from the antenna,
otherwise the airport would be a clogged mess of returns. And you're
not worried about a code that is in use but one that is not yet in use.

[Newps]

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.

[David Megginson]

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

[Newps]

Dark lonely night and you are the only airplane in the airspace
squawking VFR. You call up for service I'll give you a code and radar
contact in the same breath.

David Megginson wrote:
> 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
>
>
>
>

[unknown]

"Thomas Borchert" > wrote in message
...
> Ken,
>
> leave it on while switching. The AIM says so.
>

This is a really silly argument. Does the AIM say when you can pick your
nose or scratch your ass? Guess you better not then! What the heck are you
guys getting all worked up about? It's people who rely on a book to do all
their thinking that scare me....no ability to use common sense in an
emergency, they'll be sitting there thumbing through the AIM or the FARs
wondering what to do.....

Its too bad there's not a way to test for the ability to differentiate
between what is important and what is not. Wow....

> --
> Thomas Borchert (EDDH)
>

[Roy Smith]

"unknown" > wrote:
> Its too bad there's not a way to test for the ability to differentiate
> between what is important and what is not. Wow....

There is. Look at the age on death certificates.

[Julian Scarfe]

"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

[Ron Natalie]

"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.