View Full Version : Stansted TMZ. Mode S now Mandatory
Please note that the exemptions which allowed Modes A and C transponders in the Stansted TMZ expired on 13 September.
If you do not have a Mode S transponder, and you wish to transit the TMZ, you now have to obtain a clearance from either Farnborough Radar or Essex Radar. (132.8 or 120.625)
North Weald still have a non transponder proceedure. Please phone for details.
pudoc
17th Sep 2012, 20:03
Question RE the TMZ. I regularly hear pilots on Farnborough requesting TMZ transit (this is all pre 13th Sept.). Also, whilst flying beneath the TMZ inbound to Stapleford Farnborough have approved the QSY but told me to retain the squawk as I was under the TMZ.
My view was that the TMZ means exactly that, you need a mode S transponder switched on. I didn't think it meant you needed to squawk anything. Am I correct? If so, why has Farnborough asked me to retain the squawk multiple times? This is all pre 13th Sept and happened before and after the Olympics.
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My view was that the TMZ means exactly that, you need a mode S transponder switched on. I didn't think it meant you needed to squawk anything.
Also, whilst flying beneath the TMZ inbound to Stapleford Farnborough have approved the QSY but told me to retain the squawk as I was under the TMZ
If you are in the TMZ (you cannot be under it, as it goes down to the ground!) then you must be squawking...i.e. transponder selected on, altitude selected on, and the appropriate number selected e.g.7000, 0013( the listening squawk), 7010 (North Weald squawk) ...or as requested by Farnborough.
And yes they might ask you to retain the squawk once you leave their frequency...
See here for the AIC.
http://airspacesafety.com/media/527/stn_tmz_aic.pdf
pudoc
17th Sep 2012, 20:51
Yes - in the TMZ!
Thanks for clarifying. Why do they ask me to retain a squawk? I'm no longer in contact with them so isn't 7000 not enough?
soaringhigh650
18th Sep 2012, 00:11
Thanks for clarifying. Why do they ask me to retain a squawk? I'm no longer in contact with them so isn't 7000 not enough?
Squawks are designed to uniquely identify a flight.
Not really supposed to identify who's talking to who.
Not really supposed to identify who's talking to who.
Actually they are!
0013 indicates that an aircraft is listening to Stansted or Luton.
7010 indicates that an aircraft is in two way contact with the nearest airfield under the Stansted TMZ e.g. North Weald, Andrewsfield etc.
If there is a potential problem it allows Essex or Farnborough Radar to readily get in contact with the aircraft or airfield that it is talking to.
chevvron
18th Sep 2012, 03:07
Unlike Essex Radar, Farnborough cannot access mode 'S' information, therefore if you go to 7000 they will 'lose' your identity, so in order to continue tracking you after you leave their frequency, they ask you to retain the assigned code.
tmmorris
18th Sep 2012, 06:09
Isn't it great how they have tried to mandate carriage of Mode S equipment in aircraft (which we have to pay for) when there isn't even decent coverage at ATC units (which they have to pay for)?
Though I gather the new radar at Oxford has mode S; if so then full marks to them.
Tim
soaringhigh650
18th Sep 2012, 12:40
Not really supposed to identify who's talking to who.Actually they are!
That's simply bad design. :=
eglnyt
18th Sep 2012, 22:10
That's simply bad design.
Actually for the last 20 years it has been a very effective way of identifying who is talking to who in a non sectorised environment. Simple and effective is pretty good design.
eglnyt
18th Sep 2012, 22:17
Isn't it great how they have tried to mandate carriage of Mode S equipment in aircraft (which we have to pay for) when there isn't even decent coverage at ATC units (which they have to pay for)?
The NATS radars have national Mode S coverage. Mode S was mandated to solve issues with radio spectrum efficiency and the limited number of Mode A codes not because of the enhanced information it can provide.
chevvron
19th Sep 2012, 01:07
Radars at airports are paid for by the airport operator; mode 'S' facilities are expensive in that the SSR comes from NATS En-Route Ltd and is overlaid on the airport radar, the airport operator then having to pay NATS for the data and pay BT for the telephone line rental to receive the data and BT's charges alone ain't cheap.
As regards using unique A/C codes to identify who is actually talking to a particular aircraft, this has been used for at least 40 years not 20; LonMil and probably other Military ATCRUs certainly used it in the early '70s, the system at LonMil as far as I can recall was the first two digits indicated the unit, the third the console number and the fourth was unique to the aircraft. (may be wrong but you get my drift)
chevvron
20th Sep 2012, 09:58
Hm I was at Lindholme (on the civil consoles) for much of 1973, and as far as I recall, having only passive decoding, they only assigned the first two digits, but this could have changed after I left. I remember each miltary 'suite' had controller, tracker (operating the 'store dots') and height finder operator whereas the civl 'suites' had controller, tracker and an assistant on an edge lit perspex board on which flight data was written who ran over to the height finder if needed!
soaringhigh650
20th Sep 2012, 17:04
Actually for the last 20 years it has been a very effective way of identifying who is talking to who in a non sectorised environment. Simple and effective is pretty good design.
So why haven't you sectorized? How are people going to get a meaningful traffic/deconfliction advice when everyone is talking to someone else in the same area of airspace??!
ShyTorque
20th Sep 2012, 17:59
Because UK Class G airspace is the open FIR and in most of it it's not mandatory to carry a radio or a transponder. It could be argued that we have enough airspace restrictions already, in a relatively small and shrinking "free" environment.
soaringhigh650
20th Sep 2012, 22:10
You don't need to carry a radio or transponder even if you have sectorized.
It just means ATC is organized better, so when you want to use the radio in "the open FIR" you know who to call, rather than 7 to choose from.
reportyourlevel
21st Sep 2012, 08:25
Radars at airports are paid for by the airport operator; mode 'S' facilities are expensive in that the SSR comes from NATS En-Route Ltd and is overlaid on the airport radar, the airport operator then having to pay NATS for the data and pay BT for the telephone line rental to receive the data and BT's charges alone ain't cheap.
Not always true, we are commissioning a mode S radar that has zero to do with NATS. Paid for by the airport, our kit, our comms, our data.
chevvron
21st Sep 2012, 10:21
Your airport operator must be rich then!!
I was under the impression that all civil airports with radar had to upgrade to mode s capable but that the time frame for this had slipped a bit?
Rod1