A quick question

[ukhomerj]

As a very eager and new PPL student, can you guys please answer a question I have had for a long time.

When you issue a squawk code to an aircraft, how are these codes generated. Are they sequential or do different areas have a batch of codes for use?

Thanks dor your help.

[Bear 555]

ukhomerj,

Different Air Traffic units have their own codes, different functions have different codes (for example emergencies) - lots of variation.

I'm sure I saw a list in the AIP somewhere

Bear555

[Findo]

Local squawks are issued from a list at each SSR equipped unit. In most cases they are limited to a small block like 7201 to 7207 for one particular unit. These will normally be allocated for local flying in that ATC unit's area of responsibility.

For Airways traffic the squawks are generated from the UK allocated block and attached to the flight plan information which goes to every major UK unit. That means if you depart Heathrow and land at Aberdeen you will retain the same squawk and each ATC unit along the way will be aware of your squawk.

[SATCOS WHIPPING BOY]

Hi UKHOMERJ
The allocation of Squawks can seem confusing and complicated but there is some method in the madnessand it often it depends on the area in which you operate.
The ORCAM codes mentioned earlier are for transit ac and tend to apply to civ traffic flying airways. However, if you as a PPL holder tend to fly near Mil units and obtain a service from them then specific codes may be used, not only to help controllers identify you, but assist other controllers suss out who is working you and, to some extent, your flight conditions and type of service.

I work at RAF Linton on Ouse and, as an example, Linton Zone allocate squawks to Civ and Mil tracks dependent on Service (RIS RAS FIS), controller and task.
If I see a 4530 sqk I know that the ac is working my Zone, and receivinga Flight Information Service (FIS), so it is not unusual for multiple ac to have this sqk. This may seem strange but it allows adjacent units the opportunity to effect some coordination/traffic information if needs be; a 7000 (conspicuity)sqk could be talking to any one of about 8 units or indeed bimbling around talking to no one) whereas the 4530 lets all users know that he is at least two-way with Linton Zone. In this example RIS / RAS tracks tend to get issued sqks 4531 to 4537; if you happen to be the third radar service ac to call then expect 4533.
In addition to this Church Fenton Approach operate a similar policy but use the 4540 to 4547 series; Director has 450X, Approach 451X and departures 452X . In these examples the 45 signifies Linton, the third digit signifies the specific controller and the last digit gives either type of service(0=FIS) or track number. We follow a Code Allocation Plan and with this all operators within the approach room, and adjacent units, can quickly identify which particular controller is speaking to any ac under a service. This is of particular benefit when things get busy as we all know who to ask for info.
In this busy bit of airspace, Leeds, Teesside,Leeming, Humberside, Waddington etc all have their own allocations of sqks and issue them in a similar manner.
One important point for us as controllers is that some special sqks can imply an agreement by the pilots that they will follow a set procedure and operate not above (or below certain) levels, this allows us to effect 'deemed coordination' without disturbing either the aircrew or other controllers. In addition to all of this there are numerous County/National/International sqks that indicate what an ac is doing/experiencing/or intending to do ie radar calibration, police helo, para dropping , emergency, radio fail, unlawful interference, low level fixed-wing, low level climbout in need of radar assisted climb, royals, red arrows, etc etc etc.

As you may gather by now, the allocation of sqks is by no means random and it is important that sqks are allocated, validated and verified accordingly and that pilots not only adopt the correct sqk but remember to change it accordingly if they go 'on-route'

Hope this essay helps answer your question.
rgds
SWB:ok: :D

[FWA NATCA]

There are several methods for obtaining and issuing codes in the US.

1. Each radar facility (enroute and approach) have transponder code subsets that their facility owns that they can issue to aircraft.

In my approach control I type into the ARTS computer keypack the acft ID, press IFR or VFR and then enter, and I get a code that the computer selects in numerical order. We use 4600 range for VFR's and 5100 range for IFR's.

2. An IFR flight plan entered into the NAS computer, the computer assigns a transponder code. Sometimes an IFR acft uses the same code for its' entire flight and sometimes they have to change codes enroute.

3. A controller can randomly assign a code from the facilities subset, but they take a risk that the computer rejects that code because it is already assigned to another acft.

Mike
NATCA FWA

[Onan the Clumsy]

I get 46xx out of KDAL a lot and I was told the first two digits approximate to a controlling agency. I've had them issue a 02xx code as well promissing me that this will provide for a handoff. Usually with the 46xx codes, I'll get a "leaving my area. For further flight following squawk VFR and contact Ft Worth on <freq>"

Interestingly enough, it means my clearence out of KDAL boils down to two digits. It's always "Left turn 180, remain VFR at or below two thousand. Departure frequency is 125.2. Squawk Four Six ..... Three one"

and the 3-1 is the only part that's unknown.

[nitefiter]

just as a side issue ,when do you in atc expect to see a squawk code changed over to 7700?
A discusion arose recently during a sim check that we select 7700 in an emergency before we talk to atc,(emergency descent).
Do you as controllers expect to get the MAYDAY before that?,is it better to keep the assigned code then change when instructed??

[StillDark&Hungry]

Nitefiter

Good question, As usual I'm sure opinions will vary - At some units selection of 7700 will cancel any code callsign conversion in use so there is a possibility of "I've got an emergency on. . . . . . but who is it???"

Here at LACC our code callsign conversion is retained when 7700 is selected so we know immediately who's in trouble.

In my opinion put it on straight away, even before speaking to us. It even gives me a couple of seconds to get my head around the situation. Most of us are well aware that it's a busy time for you guys, so you don't want idle chat at the early stages of an incident. Selecting 7700 but not talking straight away would, to most ATCO's, show the seriousness of the problem, Just don't leave us in the dark too long please.
As an ECT assessor it's almost laughable to listen to some R/T exchanges in the sim like "Triple engine failure......request descent..... nearest suitable airfield....etc"
Only to hear in response; "Roger Sqawk 7700" !!!!!

[Arkady]

To add to SD&H, squawking 7700 will burn through any height filtering selected on the LACC kit. If a rapid descent is likely or desirable 7700 will help clear the sky below even before the usual round of tense telephone calls is made.

[Spank me baby!!!]

If you were to select 7700 and if you're in radar coverage. Every Air Traffic Control unit that displays the area you're in will have alarms screaming the instant the computers detect the change to 7700. The controller who's responsible for the airspace you're in will move every aircraft they can out of the way (eg. during rapid descent). The supervisor will immediately notify the Search and Rescue Co-ordination Centre. The controller will maintain a plot of your radar track until you drop below radar coverage and will attempt to call you to offer assistance. If another aircraft is close by and able to provide an escort, that aircraft will be turned on an intercept course to your flight path, or last observed position. Every attempt will be made to find out who you are, what the nature of the emergency is and what you need. If you've selected 7700, we already know WHERE you are.

...and when you make your MAYDAY call, add the number of persons on board and any dangerous cargo, because the first question we'll ask is "advise POB and dangerous cargo".

[StillDark&Hungry]

Have just been studying the UK MATS Pt 1 which states;

"To indicate an emergency condition pilots are encouraged to select code 7700 as soon as is practicable after declaring an emergency situation........"

However I still stand by my previous - don't be afraid to whack it on first:ok:

Would partly agree with Spanks, If you are carrying dangerous cargo we need to know. But I, for one, won't bother asking if you are or even for your SOB. There must be much more important things for us all to be doing!

[Cuddles]

Sort of lumped in with all this, I had an A0000 (SSR data unreliable) a few months back, and it was indicating FL560 or thereabouts.

We routinely run that sector with a height filter of FL 150, as the upper limit of the sector is FL65. Other 'odd' squawks, (ie the 77, 76, and 7500s) show up through the filter, irrespective of their level.

This A0000 didn't, and I was informed by another agency that it was operating at 2500ft. THANKFULLY I didn't have any traffic to affect, but if I had, I MAY not have popped the filter off, just to make sure, and I MAY have had an incident.

This has now been fixed, but, all of you who operate with height filters, beware.

[Andrew M]

Code Controlling Authority
0000 SSR Data unreliable
0001-0017 Allotted to France and Denmark
0020 Medivac - Air Ambulance emergency Helicopter
0021 Fixed wing (Receiving service from ship)
0022 Helicopters (Receiving service from ship)
0023 Aircraft engaged in actual SAR Operations
0024 Radar flight evaluation/calibration
0025 Not allocated
0026 Special tasks (MIL)
0027 London ACC FIS Ops
0030 FIR Lost
0031 Lost aircraft subsequently identified and co-ordination action taken with D&D
0032 Aircraft engaged in police air transport operations
0033 Aircraft Paradropping
0034 Antenna trailing/target towing
0035 Selected flights- Helicopters
0036 Helicopter pipeline/powerline inspection flights
0037 Royal Flights - Helicopter
0040 Civil Helicopters (North Sea)
0041-0057 Allotted to Belgium
0060-0077 Allotted to Ireland, Netherlands and Norway
0100 NATO
0101-0117 Transit Brussels (ORCAM)
0120-0137 Transit Germany (ORCAM)
0140-0177 Transit Amsterdam (ORCAM)
0200 NATO
0201-0227 RAF Leuchars
0201-0223 Stansted Approach (TC) Essex Radar
0201-0257 Ireland Domestic
0201-0257 RNAS Yeovilton
0220-0247 RAF Shawbury
0224-0243 Anglia Radar
0244 North Denes Conspicuity
0245-0267 Anglia Radar
0260 Liverpool Airport- IFR conspicuity purposes
0260-0261 Oil Survey Helicopters - Faeroes/Iceland Gap
0260-0267 Westland Helicopters Yeovil
0261-0267 Liverpool Airport
0270-0277 Not allocated
0300 NATO
0301-0377 Transit UK (ORCAM)
0400 NATO
0401-0420 Bristol Approach
0401-0427 RAF Leeming
0401-0437 Ireland Domestic
0401-0467 RAF Lakenheath
0421-0446 Farnborough Radar/LARS
0430-0443 Edinburgh Approach
0440-0467 RAF St Mawgan
0440-0467 ACMI( NSAR - Waddington)
0447 Farnborough LARS - Blackbushe Departures
0450-0456 Blackpool Approach
0450-0456 Farnborough Radar/LARS
0457 Blackpool Approach (Liverpool Bay and Morecambe Bay Helicopters)
0457 Farnborough LARS - Fairoaks Departures
0460-0466 Blackpool Approach
0460-0467 Farnborough Radar/LARS
0467 Blackpool Approach (Liverpool Bay and Morecambe Bay Helicopters)
0470-0477 Dutch Military
0500 NATO
0501-0577 Transit UK (ORCAM)
0600 NATO
0601-0637 Transit (ORCAM) Germany
0640-0677 Transit (ORCAM) Paris
0700 NATO
0701-0777 Transit (ORCAM) Maastricht
1000 NATO
1001-1077 Transit (ORCAM) Spain
1100 NATO
1101-1137 Transit (ORCAM) Rhein
1140-1177 Transit (ORCAM) UK
1200 NATO - Autonomous Fighter Ops
1201-1277 Channel Islands Domestic
1300-1317 Aircraft receiving service from AEW aircraft
1401-1407 UK Domestic
1410-1437 Superdomestic - Shannon to UK
1440-1477 Superdomestic- Dublin to UK
1500-1577 NATO - RAF Buchan
1600-1627 NATO - RAF Boulmer
1630-1647 NATO - No 1 ACC
1650-1657 Aircraft receiving a service from AEW aircraft
1660-1677 NATO - Plymouth (Military) Radar
1700 NATO
1701-1720 NATO - RNAS Yeovilton D School
1721-1727 NATO - Special Events (activated by NOTAM)
1730-1746 RAF Coltishall
1730-1747 Birmingham Approach, Glasgow Approach
1730-1757 Bournemouth Approach/LARS
1747 RAF Coltishall Conspicuity
1750-1757 RAF Coltishall
1760-1775 Not Allocated
1776 Manchester VFR/SVFR (Outbounds)
1777 Woodford Entry/Exit lane (Manchester inbounds)
2000 Aircraft from non SSR environment
2001-2077 Transit (ORCAM) Shannon
2100 NATO - Autonomous Fighter Ops
2101-2177 Transit (ORCAM) Amsterdam
2200 NATO - Autonomous Fighter Ops
2201-2277 Superdomestic UK to LF, Le, LP, GC and FA
2300 NATO - Autonomous Fighter Ops
2301-2337 Transit Bordeaux (ORCAM)
2340-2377 Transit Brest (ORCAM)
2400-2477 NATO -RAF Neatishead
2500 NATO - Autonomous Fighter Ops
2501-2577 Transit Karlsruhe
2600 NATO - Autonomous Fighter Ops
2601-2620 Aberdeen Approach
2601-2640 RAF Spadeadam
2601-2640 RAF Cranwell
2601-2645 MOD Boscombe Down
2601-2657 Irish domestic westbound departures and eastbound arrivals
2601-2665 DERA Boscombe Down
2621-2630 Aberdeen (Sumburgh Approach)
2631-2637 Aberdeen (North Sea off-shore Approach)
2640-2657 Aberdeen (North Sea off-shore Sumburgh Approach)
2641-2642 RAF Cranwell - Lincolnshire AIAA Conspicuity
2646-2647 MOD Boscombe Down - High Risks Trial
2650 MOD Boscombe Down Conspicuity
2650-2653 Leeds/Bradford Approach
2651-2657 MOD Boscombe Down
2654 Leeds/Bradford Conspicuity
2655-2677 Leeds Approach
2660-2675 Middle Wallop
2660-2677 Aberdeen (North Sea off-shore Approach)
2676-2677 Middle Wallop Conspicuity
2700 NATO - Autonomous Fighter Ops
2701-2737 Transit Shannon (ORCAM)
2740-2777 Transit Zurich (ORCAM)
3000 NATO - Autonomous Fighter Ops
3001-3077 Transit (ORCAM) Zurich
3100 NATO - Autonomous Fighter Ops
3101-3127 Transit (ORCAM) Germany
3130-3177 Transit (ORCAM) Amsterdam
3200 NATO - Autonomous Fighter Ops
3201-3216 UK Domestic (London ACC special sector codes)
3217-3220 UK Domestic
3221-3257 Superdomestic - UK to Oceanic via Shannon/Dublin
3260-3277 UK Domestic
3300 RN Operations
3301-3307 London (Military) Radar - Special Tasks (Sector 38)
3310-3377 London (Military) Radar
3400 NATO - Autonomous Fighter Ops
3401-3477 Not Allocated
3500 NATO - Autonomous Fighter Ops
3501-3507 Transit Luxembourg (ORCAM)
3510-3537 Transit Maastricht (ORCAM)
3540-3577 Transit Berlin (ORCAM)
3600 NATO
3601-3632 Scottish ATSOCA purposes
3601-3637 RAF Waddington
3601-3647 Jersey Approach
3601-3657 Cardiff Approach
3640-3677 Aberdeen (North Sea off-shore)
3640-3677 RAF Marham
3641-3677 BAe Wharton
3660-3677 Southampton Approach
3700 NATO
3701 RAF Lossiemouth Local Traffic
3701-3710 Military aircraft under service from RN AEW aircraft in South West Approaches
3701-3710 RAF Coltishall/Norwich Approach
3701.3710 BAe Woodford
3701-3747 Guernsey Approach
3701-3757 RAF Brize Norton
3702-3734 RAF Lossiemouth/Kinloss
3711 Norwich Approach Conspicuity/ Woodford Entry/Exit Lane (Woodford inbounds and outbounds)
3720-3757 RAF Coningsby
3720-3767 RAF VAlley
3730-3776 Newcastle Approach
3760-3773 Gatwick Approach (TC)
3774-3777 Gatwick Tower
3777 Newcastle Approach Conspicuity
4000 NATO
4001-4077 Transit Aix-en-Provence (ORCAM)
4100 MPA/DEFRA/Fishery Protection Conspicuity
4101-4127 Transit Frankfurt (ORCAM)
4130-4177 Transit Dusseldorf (ORCAM)
4200 NATO
4201-4214 Heathrow Domestic
4215-4245 Superdomestic-Dublin inbound UK
4246-4247 Stansted Approach
4250-4277 BAe Filton
4250 Manston Conspicuity
4251 Manston Special/Test Flight conspicuity
4260-4277 Humberside, Aldergrove Approach
4300 NATO
4301-4306 Not Allocated
4307 Height Monitoring Unit
4310-4321 Gatwick Domestic
4322 Not Allocated
4323-4356 Manchester Domestic
4357-4377 UK Domestic
4400 NATO
4401-4427 Superdomestic-Brussels FIR to UK FIR
4430-4447 Superdomestic-UK to Eire and Oceanic
4500 NATO
4501-4520 Prestwick Approach
4501-4527 RAF Lyneham
4501-4547 RAF Linton-on -Ouse
4530 RAF Lyneham FIS Conspicuity
4530-4542 MOD Aberporth
4550-4567 Isle of Man
4550-4573 East Midlands Approach
4560-4573 RAF Odiham
4574 East Midlands Police ASU
4575 RAF Leeming/RAF Linton-on-Ouse/Southend Airport Conspicuity
4576-4577 Vale of York AAIA Conspicuity/RAF Colerne Conspicuity
4600 NATO
4601-4607 RAF Wittering/RAF Cottesmore
4601-4620 Plymouth (Military) Radar
4601-4677 Scottish ACC (Military)
4610-4640 RAF Cottesmore
4650-4651 Coventry Approach
4654 North Midlands Police ASU
4656 Cambridge Approach
4657 Cambridge Airport Conspicuity
4660-4677 Luton, Exeter Approach
4670-4677 MOD Llanbedr
4700 NATO
4701-4710 SAR Exercises/Special Event (activated by NOTAM)
4711-4757 Tactical Leadership Programme
4760-4777 Special Events (activated by NOTAM)
5000 NATO
5001-5012 Special tasks
5013-5077 UK Domestic
5100 NATO
5101-5137 Superdomestic - UK to Scandinavia and Russia
5140-5177 UK Domestic
5200 London ACC Saturation Code
5201-5260 Transit UK (ORCAM)
5261-5270 Transit Dublin to Europe (ORCAM)
5271-5277 Transit Channels Islands (ORCAM)
5300 NATO
5301-5377 Transit Barcelona (ORCAM)
5400 NATO
5401-5477 UK Domestic
5500 NATO
5501-5577 Transit Barcelona (ORCAM)
5600 NATO
5601-5657 Transit Paris (ORCAM)
5660-5677 Transit Reims (ORCAM)
5700 NATO
5701-5777 Transit Geneva (ORCAM)
6000 NATO
6001-6007 London D+D Cell
6010-6077 London (Military) Radar
6100 NATO
6101-6164 London (Military) Radar
6165-6177 Not Allocated
6200 NATO
6201-6210 Superdomestic-Shannon eastbound landing UK
6211-6225 Not Allocated
6226-6247 UK Domestic
6250-6257 Superdometsic - UK to Amsterdam
6260-6277 Superdomestic- Amsterdam to UK, Eire and Iceland
6300 NATO
6301-6307 Not Allocated
6310-6327 Pennine Radar
6320-6327 RAF Northolt
6330-6337 Hawarden
6340-6377 Superdomestic-London to Paris
6400 NATO
6401-6477 LJAO
6500 NATO
6501-6577 Not Allocated
6600 NATO
6601-6677 Transit Germany (ORCAM)
6700 NATO
6701-6747 Transit Reims (ORCAM)
6750-6777 Transit Aix-en-Provence (ORCAM)
7000 Conspicuity Code (Standard mode C initial contact code)
7001 Military LOw Level Climbout/Conspicuity
7002 Danger Areas General
7003 Red Arrows Transit/Display
7004 Conspicuity Aerobatics and Display
7005 Merseyside, Cambridgeshire Police
7006 Lancashire, Suffolk Police
7007 Open skies observation aircraft
7010-7013 Not Allocated
7014 Northumbria, Cheshire Police
7015 Northumbria, South/East Wales, South Yorkshire Police
7016 Height monitoring unit
7017 Humberside, Western Counties Police
7020 Strathclyde Police
7021 Greater Manchester Police
7022 Sussex Police
7023 Essex Police
7024-7025 London Heathrow Met Police
7026 Thames Valley Air Ambulance
7027 Not Allocated
7030-7047 Thames Radar-Special VFR
7030-7076 Teesside Airport
7030-7077 Aberdeen (Northern North Sea Offshore)
7050-7067 Thames Radar-London City Approach
7070-7073 Thames Radar-Heathrow
7074-7076 TC Heathrow Approach
7077 Thames Radar-Battersea Helicopters
7077 Teesside Airport Conspicuity
7100 Thames Radar-(Flying Eye)
7101-7177 Transit Brussels (ORCAM)
7200 Thames Radar-(Flying Eye)
7201-7247 Transit Vienna (ORCAM)
7250-7257 Superdomestic-UK to France and Barcelona FIR
7260-7267 Superdomestic-Shannon/Dublin to France and Barcelona FIR
7270-7277 Plymouth Radar Superdomestic for destinations in UK and France
7300 Chiltern Police
7301-7307 Superdomestic-Shannon eastbound landing UK
7310-7327 Superdomestic-UK to Netherlands
7330-7347 Superdomestic-Netherlands to UK
7350-7361 MOD Ops in EG D701 (Hebrides)
7350-7373 Manchester Approach /RAF Benson
7350-7377 RNAS Culdrose
7362 MOD Ops in EG D702 (Fort George)
7363 MOD Ops in EG D703 (Tain)
7374 RAF Odiham
7375 Manchester TMA and Woodvale local
7376 Luton Airport TWR, West Yorkshire Police
7377 Cumbria, West Midlands Police
7400 Chiltern Police
7401-7407 ScoACC Special Sector codes
7410-7477 UK Domestic
7500 Hijack Code-Special Purpose Code
7501-7537 Transit Geneva (ORCAM)
7540-7547 Transit Bremen (ORCAM)
7550-7577 Transit Paris (ORCAM)
7600 Radio Failure-Special Purpose Code
7601-7677 Superdomestic - UK to USA
7700 Emergency-Special Purpose Code
7701-7717 Superdomestic - UK to France and Spain
7720-7727 Transit Amsterdam (ORCAM)
7730-7757 Superdomestic-Shannon eastbound landing UK
7760-7775 Superdomestic-UK to Channel Islands
7776-7777 SSR Monitors

Sorry about the length of the post !

[nitefiter]

Thanks guys looks like 7700 right away then.
Andrew M
You need help!!

[Andrew M]

You need help!!

thank you, my pleasure..... :D

[FWA NATCA]

Nitefiter,

I've seen pilots that are receiving radar service declare emergencies and never squawk 7700, most instances where I have seen 7700 is when the acft isn't recieving ATC services (VFR) and encounters a problem and sqawks 7700 and yells Mayday on the Guard freq.

If you are just flying around VFR (1200 code) and turn your transponder to 7700 I will see your VFR tag change to 7700 and the letters EM, plus an alarm will sound in the tracon.

If you are VFR or IFR and on a descrete code receiving ATC services I will see "EM" flash in you data tag, plus I will see a message in my systems area with your aircraft ID and the word Emergency and the alarm will sound.

Example: IFR acft
N1234CH
040 120EM

VFR acft:

* - 7700 EM
085 120

This data tag will flash to draw my attention to it.
The first line is your acft ID, the second line is altitude and airspeed. The EM is what I see in you data tag that tells me that you are squawking 7700.


Mike
NATCA FWA