Squawk starting with 7

MSmith

MSmith

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Mark Smith
This weekend I did my first IFR XC training flight.

One odd thing about the flight was that my squawk assigned by McGuire Clearance was 7174. This is the first time that either I or my instructor has ever heard of a squawk being assigned starting with a 7. We had the controller repeat it twice.

Did we get used for tracking practice? Is there some other reason? Or were they just running out of numbers?
 
i dunno, as far as i know, squawks starting with 7 are generally avoided to prevent accidentally dialing in an emergency squawk. at least thats what i was told in ground school.
 
tonycondon said:
i dunno, as far as i know, squawks starting with 7 are generally avoided to prevent accidentally dialing in an emergency squawk. at least thats what i was told in ground school.
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That was probably true when we didn't have so many GA pilots on discrete squawks and stupid things like the Washington ADIZ eating up available codes. Kinda like the old AT&T national numbering plan with easily recognizeable differences between area codes and exchange prefixes.

AFaIK the only unuseable codes are 0000, 7700, 7600, and 7500.
 
lancefisher said:
That was probably true when we didn't have so many GA pilots on discrete squawks and stupid things like the Washington ADIZ eating up available codes. Kinda like the old AT&T national numbering plan with easily recognizeable differences between area codes and exchange prefixes.

AFaIK the only unuseable codes are 0000, 7700, 7600, and 7500.
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You can add 1277 to that list. It is a Coast Guard Squawk for an aircraft on a S&R mission in VFR conditions.
 
smigaldi said:
You can add 1277 to that list. It is a Coast Guard Squawk for an aircraft on a S&R mission in VFR conditions.
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I think there may be several others with specific meaning (like 1200 for instance), but those are all valid codes for "normal" ops. 7700,7600,7500 are as we all know emergency codes and 0000 is never used for reasons I forgot.
 
lancefisher said:
I think there may be several others with specific meaning (like 1200 for instance), but those are all valid codes for "normal" ops. 7700,7600,7500 are as we all know emergency codes and 0000 is never used for reasons I forgot.
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1277 is not a normal ops code. As I stated it is for search and recovery aircraft on a SAR mission. To use that code you have to be a valid aircraft and cannot just go squaking it because you are flying around.
 
0000 is used for target practice, IIRC. Its what the drones use when the military is testing missiles
 
tonycondon said:
0000 is used for target practice, IIRC. Its what the drones use when the military is testing missiles
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I think that gives us a good reason not to use it!
 
smigaldi said:
1277 is not a normal ops code. As I stated it is for search and recovery aircraft on a SAR mission. To use that code you have to be a valid aircraft and cannot just go squaking it because you are flying around.
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Scott,

Except for very few codes such as 1200 (VFR), 1201 (VFR in LA SFR), 1204 (VFR helo at VNY) and the emergency codes (7700,7600,7500) you should not squawk any other code without it being assigned to you.

I'm not sure you'd have any less trouble if you were squawking 1234 than 1277.

Joe
 
Areeda said:
Scott,

Except for very few codes such as 1200 (VFR), 1201 (VFR in LA SFR), 1204 (VFR helo at VNY) and the emergency codes (7700,7600,7500) you should not squawk any other code without it being assigned to you.

I'm not sure you'd have any less trouble if you were squawking 1234 than 1277.

Joe
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Don't disagree but lance said " but those are all valid codes for "normal" ops." I am stating that 1277 is not a normal ops code and is not to be used except for certain cirumstances, it is a reserved codes and once would not expect it to be assigned to them.
 
OK, now that we have that straightened out.

Does anybody know anything about the assignments of 7xxx codes (other than the designated 3)?
 
I've gotten IFR squawks of 7xxx
 
OK - I guess they're just using that range these days.

One theory is that they started using 7's because they were running out in the vicinity of the DC ADIZ. Southern NJ is not too far from there.
 
I've gotten VFR flight following squawks in the 7xxx range a couple of times. First time was when we found out that the XPDR in the 152 wouldn't go past 5777. heh.

But for safety sake, when given a 7XXX squawk, I always changed the numbers from right to left. When leaving a 7XXX squawk, I went left to right. I think that makes it impossible to hit an emergency code. (I could be wrong, I just woke up and the power had been off for 2 hours... power company red tagged the wrong meter... grr.)
 
wbarnhill said:
But for safety sake, when given a 7XXX squawk, I always changed the numbers from right to left. When leaving a 7XXX squawk, I went left to right. I think that makes it impossible to hit an emergency code.
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I thought about that, but I was setting it up on the ground on Standby anyway. When they cut me loose after cancelling IFR, my instructor changed the code because I was in the middle of an approach.
 
Areeda said:
Scott,

Except for very few codes such as 1200 (VFR), 1201 (VFR in LA SFR), 1204 (VFR helo at VNY) and the emergency codes (7700,7600,7500) you should not squawk any other code without it being assigned to you.
...
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The BRITE slaved towers can give you a 12nn squawk. I've heard DPA tower give "IDENT" or "squawk 1201." PWK has on the ATIS "VFR departures squawk 1205 until 5nm from Palwaukee, then squawk 1-2-0-0." I suppose that clues in C90 where you came from when you show up so close to O'Hare.

At one Young Eagles rally at Meigs, the controller was giving out squawks to VFRs in sequence and we were supposed to keep them all day until we left. When I heard him say to plane behind me something like, "Cessna nnnn, squawk 1228" I thought there was something strange about that. So did the pilot who after a while came back and said he can't do that. He did admit he tried first. :p "Correction Cessna, squawk 1230"
 
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Squawks of 76XX and 77XX all set off alarms in the tower. Doesn't need to be 7600 etc.
But only 7500 sets off alarms.
See aim 4-1-19 e 1
So avoid all codes that start with 76 and 77
 
There are a couple of other 12xx reserved squawks for DC ADIZ ops. In any event, 7xxxx (other than 76xx, 77xx, and 7500) is not an unusual ATC squawk. Just be careful when dialing it in so you don't spin through 76xx or 77xx.
 
MSmith said:
This weekend I did my first IFR XC training flight.

One odd thing about the flight was that my squawk assigned by McGuire Clearance was 7174. This is the first time that either I or my instructor has ever heard of a squawk being assigned starting with a 7. We had the controller repeat it twice.

Did we get used for tracking practice? Is there some other reason? Or were they just running out of numbers?
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I've had a 7xxx code twice, both within the last 6 weeks or so. Once was with my CFII, and he commented "Those are the codes you need to tune VERY carefully." The other was just a week ago when I flew my first "real" IFR (read: I didn't have to climb to 7,000 to get some actual) trip.

Threw me for a loop too, but I guess it's normal. Figure there can be 6000-8000 planes in the air, IFR, over the US at busy times, and we only have (8^4)-7 = 4089 codes to work from. (minus 0000, 7500, 7600, 7700, 1200, 1234, 1277.) I know there are blocks that are reserved for certain areas and can be reused (for instance, VFR aircraft in MSN airspace get a 04xx squawk and "Local IFR" aircraft that aren't leaving MSN airspace get a 01XX squawk) which is how we manage to have more aircraft than codes at any given time. There's probably a block of codes for aircraft staying within one Center's airspace too.

FWIW, my 7xxx code last weekend was for a flight from STE (Minne Center) to MSN (Chicago Center). Did you cross a center boundary during your flight?
 
Ron Levy said:
Just be careful when dialing it in so you don't spin through 76xx or 77xx.
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Ron, is the problem 76xx, 75xx, 77xx or is it 7600, 7500, 7700?

In other words if you spin through 7623 is that a problem?

-Skip
 
In addition to what the others have said.... Also note that any (normal op.) transponder code that ends in 00 (eg: XX00) is a NON-descrete beacon code.

Descrete and non-descrete environments are defined as: NOTE-
A code environment is determined by an operating position's/sector's equipment capability to decode radar beacon targets using either the first and second or all four digits of a beacon code.

If you all are looking for more codes that ATC can't assign (due to special purposes), check out Chapter 5, section 2 of the FAAO 7110.65R: (specifically 5-2-6)
Jason
 
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Ron Levy said:
Just be careful when dialing it in so you don't spin through 76xx or 77xx.
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For years I have been in the habit of turning my transponder to standby while dialing to avoid that.
 
Skip Miller said:
Ron, is the problem 76xx, 75xx, 77xx or is it 7600, 7500, 7700?

In other words if you spin through 7623 is that a problem?

-Skip
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Not ron but the first two letters of our first name are the same, which is good enough for 76xx and 77xx. 7500 doesn't have this problem.
According to the AIM 7623 would raise an alarm, where 7523 wouldn't.
 
wbarnhill said:
But for safety sake, when given a 7XXX squawk, I always changed the numbers from right to left. When leaving a 7XXX squawk, I went left to right. I think that makes it impossible to hit an emergency code.
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Yes, covered that in ground school a couple of decades ago. First record I have of being assigned a 7xxx squawk was in 1989. Don't think this is very new.

Regards,
Joe
 
smigaldi said:
Don't disagree but lance said " but those are all valid codes for "normal" ops." I am stating that 1277 is not a normal ops code and is not to be used except for certain cirumstances, it is a reserved codes and once would not expect it to be assigned to them.
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I guess I couldn't come up with a better description than "normal ops", but I meant non-emergency, not "out flying around", but what I was really thinking was that all that the rest are assigned by the FAA. All other codes are assigned one way or another. 1277 is likely assigned by some letter of agreement or similar document. 1200 is assigned by FAR. Others are assigned by FAA procedures etc. But even 7700, 7600, and 7500 are assigned to aircraft in distress by FAA decree or reg so my distinction is kinda falling apart.
 
lancefisher said:
I guess I couldn't come up with a better description than "normal ops", but I meant non-emergency, not "out flying around", but what I was really thinking was that all that the rest are assigned by the FAA. All other codes are assigned one way or another. 1277 is likely assigned by some letter of agreement or similar document. 1200 is assigned by FAR. Others are assigned by FAA procedures etc. But even 7700, 7600, and 7500 are assigned to aircraft in distress by FAA decree or reg so my distinction is kinda falling apart.
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The master list of which organization gets which code is the National Beacon Code Allocation Plan. I haven't been able to find it published anywhere and suspect that it's classified. You can glean parts of it from Section 5-2 of the Contoller's Handbook which Jason gave a reference to earlier. That section makes clear that all other codes are not assigned by the FAA, some belong to DOD. Other codes which may be assigned by the FAA have special purposes, eg: only for flight above FL600. Discrete codes 1255 and 1277 similarly have special status.

The NBCAP also details which Centers have which pools of codes. The plan tries to keep adjacent facilities from sharing the same pool so that there's no confusion when radars overlap. There's a similar allocation for Approach Controls but I don't know if it's handled at the National or Center level.

Regards,
Joe
 
flyingcheesehead said:
Figure there can be 6000-8000 planes in the air, IFR, over the US at busy times, and we only have (8^4)-7 = 4089 codes to work from. (minus 0000, 7500, 7600, 7700, 1200, 1234, 1277.)
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There are a few more codes that can't be used, but it's not a significant number. However, it's the Center computers that manage the codes, not a national one, so one code can be in use in several centers at once. There's an interconnect to check for simultaneous use when an aircraft will transit several Centers' airspace on its flight, and block that code in all affected Centers, but other than that, a single block of codes (e.g., 41xx) could be used for VFR traffic in SoCal, Potomac, Chicago, and Dallas TRACONs all at the same time. Thus, the ATC system can have a lot more aircraft in it at one time than the math above suggests.
 
Ron Levy said:
There are a few more codes that can't be used, but it's not a significant number. However, it's the Center computers that manage the codes, not a national one, so one code can be in use in several centers at once. There's an interconnect to check for simultaneous use when an aircraft will transit several Centers' airspace on its flight, and block that code in all affected Centers, but other than that, a single block of codes (e.g., 41xx) could be used for VFR traffic in SoCal, Potomac, Chicago, and Dallas TRACONs all at the same time. Thus, the ATC system can have a lot more aircraft in it at one time than the math above suggests.
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That probably explains why when I was flying to KC a couple of weeks ago on a handoff from Chi-Center to KC-Center I got a squawk change. I did not get one on they way back, must have been no conflict.
 
Ron Levy said:
There are a few more codes that can't be used, but it's not a significant number. However, it's the Center computers that manage the codes, not a national one, so one code can be in use in several centers at once. There's an interconnect to check for simultaneous use when an aircraft will transit several Centers' airspace on its flight, and block that code in all affected Centers, but other than that, a single block of codes (e.g., 41xx) could be used for VFR traffic in SoCal, Potomac, Chicago, and Dallas TRACONs all at the same time. Thus, the ATC system can have a lot more aircraft in it at one time than the math above suggests.
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Aha... That is more efficient than my guess of some codes being restricted to intra-Center use only.

I guess I didn't think the ATC computers were actually that sophisticated. :rofl:
 
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