New Squawk???

[Hufl]

Hi
I´m just wondering what´s it all about with the new squawks??? Sometimes you fly 12 hours with one squawk and sometimes you get 3 new in half an hour, especially in Europe!
So, do you get payed for assigning new squawks???

Hufl:D

[Carbide Finger]

Hufl,

Squawks are issued on a regional basis. Certain routes attract certain squawks. I think there's an ORCAM (Originator Region Code Allocation Something or Other) in the AIP somewhere www.ais.org.uk Page ENR 1-6-2-4 to be exact

If you are coming through Swanwick's airspace, you may get a squawk change due to an AU message (your A/C doesn't enter via the expected entry fix). When the AU is given a proper route NAS will automatically issue another code from London FIR's batch.

Also, if you change to another unit (Swanwick Mil, for instance), the unit handing over will change the squawk before handing you over.

In answer to your 12 hour statement. If you fly across the Atlantic. The squawk issued over there is transmitted via the ATC network with the estimates for various FIRs

Hope this helps.

Regards

CF

[jEtGuiDeR]

Yes, we also get a bonus for getting you to "ident"!! :p

[DFC]

It might also be worth pointing out that the UK does not have an integrated ATC system for civil data as such and in order to identify who is working certain aircraft each unit is assigned certain groups of codes.

On the airways system the single UK computer is used by all and thus you keep the code from start to finish. Leave the airways and each unit will give you a new code simply because they have to in order to show other units that they are talking to you.

Many other places have an integrated system and you keep the same code from start to finish and the ATCOs simply right click and change the return data label to show who is working the aircraft.

Mode S will change all that......so what is the UK plan for ensuring that radar units are aware of who (if anyone) is working G-ABCD plodding along about to get in front of the IFR (RAS) inbound?

Regards,

DFC

[5milesbaby]

Not give the RAS in the first place, oops wrong thread :E

Squalk saturation plays a little part too, so if an appropriate ORCAM code isn't available, a domestic one is issued and will probably need changing by every new centre you talk to. Another problem is that if you are only in the first centres airspace for a short time, your code can be reissued quickly, which may then still be worn by the previous a/c inside a much larger FIR when you enter, hence new squalk needed.

[Scott Voigt]

In the US you will only have to change your code if it is already being used by someone else when you enter the next enroute facility. (Yes we do run out of codes from time to time with all the aircraft...)

regards

Scott

[threemiles]

Here are the documents that are explaining all the squawk stuff. This is a highly regulated procedure that reaches from the Atlantic to the Pacific trying to make best use of the 4096 squawks available.

(Unfortunately the second document take 200 pages or so)

General rules:
http://www.icao.int/eurnat/edocs/CAL_Ed2_Amd3_PartA.pdf

Table listing of squawk groups:
http://www.icao.int/eurnat/edocs/CAL_Ed2_Amd3_PartB.pdf

[DFC]

Don't you just love the old.........we are so short of codes..........4096 codes give us so few to assign that when it gets busy the system can not cope without having to asign local codes.

Rubbish (to a certain extent).

If the system was so short of codes then why do units like Franborough assign individual codes to VFR flights in class G airspace getting only a flight information service?

Why not give all such flights the same code (tells everyone who is working the aircraft) and give the codes thus made available back into the pot to be assigned to enroute allocations where there can be a shortage at peak times?

Regards,

DFC

[5milesbaby]

If they were all on the same code then they wouldn't be identified or verified, therefore pointless. That's what 7000 is for. By each having its own code then the units that can decifer the working agency can work out if the code is validated and verified.

[DFC]

One could ask why identify and verify VFR flights on FIS?

How about FIS being a common service regardless of unit be it Area FIS, APP or LARS. Perhaps then pilots would understand it a bit better and not expect more than they get.

However, as I undestand the rules 7000 can not be used to establish identity and consequently the level can not be verified.

There is nothing in the rules however that prevent you using primary radar techniques to identify an aircraft that is on a 7000. :)

If however, a LARS unit gave all the VFR flights a single assigned code then everyone knows that they are in contact with.

The whole idea is simply to leave more codes available for aircraft getting or more appropriately, needing a radar service.

Regards,

DFC

[Pierre Argh]

DFC

allocate a single squawk to FIS tracks... brilliant, but actually that's what many units do already? Check the SSR Code Allocation Table and you will find many units have their own conspicuity codes. These are used to distinguish to adjacent radar units traffic that whose SSR Mode C (height readout) is unverified... (i.e may be unreliable for height separation purposes)that's all, no guarantee that the track is either VFR or under FIS... but likely.

For myself, if I get a lot of traffic working close to our zone (or transiting through it) I will allocate individual squawks to maintain track identity... the pilot's not getting a radar service, but it speeds up/simplifies the process if/when I need co-ordination. We have a small code block... but manage OK, with multiple use of the conspicuity code when necessary... Funny how often I allocate this and another pilot will chirp up and say "I'm already squawking ****!).... well done for paying attention.

There are few rules for use of a unit's SSR Codes, and at many controllers use them at their discretion... What has always puzzled me is why there are so many separate codes for Police helicopters... I assume they rarely operate in the same airspace, are VFR/FIS most of the time... and one code is surely enough (like air ambulances & SAR helos have)?

The original question has been well asnwered... units have their own codes, there is at present no system in the UK to carry the codes forward from one unit to the next... but as someone has said that may be one of the advantages of Mode S?

[Another_CFI]

DFC, As a pilot who receives a FIS from Farnborough many days per week I believe that their allocation of individual squawks to aircraft receiving only a FIS is a matter of pragmatism. In addition to the aircraft to whom they are providing a FIS they are also handling their own IFR inbounds/outbounds plus those from the Farnborough clutch.

Due to the number of aircraft in the open FIR, plus the gliders from Lasham it is often necessary for the EGLF controllers to negotiate with an aircraft receiving a FIS and agree a temporary limitation on their operation (eg “not above 2400ft”, “route to the east of the field”, etc) in order for the EGLF inbound/outbound to be handled efficiently. Without individually identifiable aircraft this would not be possible.

[spekesoftly]

What has always puzzled me is why there are so many separate codes for Police helicopters... I assume they rarely operate in the same airspace .............

In the North West, for example, there are at least five Police Air Support Units (N.Wales, Lancashire, Merseyside, Manchester and Cheshire ASUs), and quite often there can be three or more of their aircraft simultaneously working either Manchester or Liverpool ATC. Discrete SSR codes for each ASU therefore works well. It just a shame that when the ASU callsigns were re-organised, a while back, that Merseyside's and Cheshire's now sound so similar! :(

[Minesapint]

DFC

I am afraid that we are short of codes, most of the European core states are (not Spain, Germany or France though - yet). The problem is that only certain codes can be used in certain areas. For example, domestic codes should only be used within the country that they are allocated to and then only to within 30Nm of the FIR boundary (PANS ATM or EUR CAL). Transit codes are used for crossing PA boundaries and then there are superdomestic and supertransit, sub domestic and military not forgetting NATO.

I am reliably informed that the UK may well have a problem prior to Mode S circa 2012 (ish). Hey, just in time for the Olympics! I actually believe the current plan is to replace Swanwick systems in 2012 too, now that will be fun!!!

[Evil J]

I was actually thinking the other day how often I see our local police helicopter up near Hull; looked it up and turns out the one based up there has the same assigned squawk-so I wouldn't say they could use the same one-mind you the Helimeds do and that works OK...?

[Minesapint]

DFC

I am afraid that we are short of codes, most of the European core states are (not Spain, Germany or France though - yet). The problem is that only certain codes can be used in certain areas. For example, domestic codes should only be used within the country that they are allocated to and then only to within 30Nm of the FIR boundary (PANS ATM or EUR CAL). Transit codes are used for crossing PA boundaries and then there are superdomestic and supertransit, sub domestic and military not forgetting NATO.

I am reliably informed that the UK may well have a problem prior to Mode S circa 2012 (ish). Hey, just in time for the Olympics! I actually believe the current plan is to replace Swanwick systems in 2012 too, now that will be fun!!!