MATZ squawks

[ozplane]

I've just returned from Wickenby and was working Cottesmore. I asked for Flight Info and was given the squawk 4640 (I think). A few minutes later another a/c came on frequency and was given the same squawk. I queried this and in the nicest possible way the lady controller informed me it was the common code for Flight Information Service ex Cottesmore. Whenever I've done this before the squawks have been sequential e.g.4640,4641 etc. I would have thought that 2 a/c using the same squawk would have caused confusion or am I missing something?

[NinjaBill]

Each matz only has 10 numbers each, so on a busy day, they would run out if they gave everyone a separate number. At leeming, it seems to be common for aircraft who are only requesting FIS in VFR to be given 0401, ie aircraft not under control of that radar, and the other 9 to be given to aircraft that need an individal squark, ie those requesting RIS/RAS or flying IFR

NB

[Circuit Basher]

On Sunday, all VFR aircraft passing through Fenton zone requesting FIS (at least for the duration I was in radio contact with Fenton) seemed to be given a squawk of 4640. Linton LARS had shut down by the time we were trying to talk to them, so I still have never yet had the benefit of a LARS service!

[topcat450]

I've often heard several a/c on one frequency get the same squawk. IIRC, near Birmingham somone there (Cov?) gave VFR FIS one squawk code, and IFR another. But all the Cessna's buzzing around had the same code.

[Bright-Ling]

It is used, not for positive identification, but has its benefits. Other units know who to phone if seen to conflict with their traffic, also helps them if one of the maggots on the screen is still wearing there squawk 80 miles out....... you forgot to dump the traffic!!

Everyone wearing the same squawk is also being used by the FIS London FIR - 0027 is it not?

[Chilli Monster]

ozplane

As FIS is technically a non-radar service it doesn't matter if you all wear the same squawk. Most military units now have a 'FIS' squawk (have a look at the SSR allocation plan in the UK AIP). The reason for it is just to 'tag' you as traffic working that unit. Should you be working that unit and require a RIS or RAS you'll find you will be issued a different squawk unique to you while you work that unit.

[FlyingForFun]

Last Saturday, Lyneham gave me the same squawk as others on frequency. This wasn't just for a FIS either, it was for clearance to transit their Class D. And they were able to use their radar to inform me when I was entering their airspace, and to give me my position when they handed me over to the next frequency, despite what Bright-Ling says. They identified me by having me squawk Ident after giving me the squawk, and I presume the traffic was light enough that having identified each aircraft they could remember which was which. I'd also imagine that since I was not being given an official radar service, they wouldn't be allowed to give me radar vectors, but I don't know?

Not sure what this adds to the conversation, but I thought I'd say it anyway!

FFF
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[eyeinthesky]

Bright-ling:

Careful, the 0027 squawk is ONLY allocated by London FIS to traffic to which they are talking and which is requesting a join or cross of controlled airspace. It is used to identify that particular 'maggot' from all the other 7000s out there when they ring the relevant sector and ask for joining clearance.

0027 is not for general use without being asked to put it on, otherwise it loses its effectiveness.

[BEXIL160]

FFF...

Actually outside the class D all you got was a FIS. The fact that you were issued a squawk and even identified by the controller means nothing more, nothing less.

Even crossing the class D you were not (officially) in reciept of a radar service, unless the contoller uttered the magic words "RADAR CONTROL SERVICE" as you entered the Zone. You were in receipt of an Approach Control Service and Issued with a (Procedural) Crossing Clearance.

The fact that the controller identified you just made the issuing of the crossing clearance easier for him/her. You are right. No RADAR service (RCS/RAS/RIS), no headings.

Point to remember however. In Class D separation is not required to be provided by the controller between VFR and VFR flights, or between IFR and VFR flights. Traffic info will be provided and most ATCOs in the UK will attempt to "de-conflict" IFR and VFR flights, if not provide full separation. This is a BIG discussion point in itself and if you want to open a really big can of worms, post a question about it on the ATC forum.

Best rgds
BEX

[Flyin'Dutch']

Been in the fortunate position to visit West Drayton and Swannick over the last month.

So good to have a look at the other side of the fence. Should be made compulsory for any PPL student.

They are a rather super bunch of folk working very professionally and having to cope at times with some pretty lousy amateurs from our midst, just have a listen to 124.6 on a sunny day and you see what I mean.

Ozplane :

Not surprising you asked (if in doubt always do) because I am sure there are many many GA pilots who don't know about this use of TXPDR codes.

The more I know the more I know that I don't know.

Have fun

FD

[FlyingForFun]

Bex - you are absolutely right, I did receive a FIS outside of controlled airspace. Inside controlled airspace, I received more, though, so my point about shared squawks being used for more than just a FIS is still valid.

I'm aware that I don't get any separation in Class D, and I don't expect any. But I do find it scary how few pilots are actually aware of what separation they do and don't get in each class of airspace - I remember sitting in the canteen at the CAA's office at Gatwick, the night before my ATPL Air Law exam, trying to figure out a way of helping a fellow student, and an experienced military pilot, remember the rules. But this is probably a topic for another thread, if anyone's interested enough to start one.

FFF
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[Evil J]

Perhaps some military ATCO's on here could help, but I think the military have different rules about identification. Flying around Scotland last year I was frequently identified on the basis of a 7000 ident. So it MAY be the case that a FIS conspicuity squawk issued and then idented could be good for an ident? I don't know that but I think it slightly pressumptious to apply civil regs to military units who may not be singing from the same hymn sheet.

[Whipping Boy's SATCO]

Evil J, aircraft can be identified in a plethora of ways. Sticking with SSR, there are basically 3 methods:

1. Observance of compliance with an instruction to set an assigned 4 digit code (ie "GABCD Sqk 1234").

2. Observance of a pre-assigned 4 digit code (ie, ac gets given sqk on taxy, the radar controller observes the assigned code on departure).

3. Observance of an "ident" after a pilot has been instructed to operate the ident facility (regardless of code).

In all these cases (and especially the third), controllers should, where possible, also ensure that the location of the observed code correlates with other radar or non-radar derived info. For example, if you sqk ident having informed the controller you are over the Forth Road Bridge but he/she sees the ident over Dundee they must make further efforts to positively identify you.

Finally, a controller may allocate the same sqk (from his allocated block) to any number of ac regardless of type of service. The only problem is that this will quickly lead to confusion!

[ShyTorque]

Coventry also give multiple aircraft the same squawk, 4650 for VFR and 4651 for IFR. I understand this is for the benefit of Birmingham, who control the overlapping airspace, as Cov have no SSR of their own.

It's also my understanding that you can request and receive a radar information or even a radar advisory outside class A or D airspace. Whether you get it or not is subject to ATC agreement and ability to do so. If not, I've been hoodwinked for a number of years now.

I can't actually think of an occasion when I've NOT been given "radar control" when crossing class D, even when VFR. I always accept (because otherwise ATC will probably ask for the present heading and give the reciprocal to vacate the airspace).

[BEXIL160]

Shy...

Quite right, outside Class ABCD you may request a RIS or a RAS, it's up to you to ask irrespective of your flight rules (IFR or VFR) and flight conditions (IMC or VMC). Provision of that service is down to the ATCU concerned. They may be able to help you, they may not. It depends on a lot of factors (controller workload, your alt, radar coverage, are a few examples). Don't be afraid to ask.

Inside class D (or A/B/C) you don't get a choice. You are either placed under a Radar Control Service or you aren't. It's not a question of accepting the service or asking for it. Now if you are operating under VFR and have been given a crossing clearance based on that fact, the controller concerned might ASK if you can accept radar vectors if neccesary, AND MAINTAIN VMC. If you can't he will have to think of another plan.

It's entirely possible to cross class D and NOT receive a Radar Control Service. You would be in receipt of a "procedural" crossing clearance and would be under an Approach Control Service. Given that you are VFR, its doesn't mean a whole lot, as the controller concerned isn't responsible for your separation from everyone else, you are.

See, can of worms isn't it? Throw in "Duty of Care" and you will see why some ATCOs have serious problems with VFR ops in class D airspace.

Rgds BEX