Mode S transponders

[MAN777]

Is mode S going to be compulsary for all aircraft ? and if so what exemptions are there likely to be, for the likes of military and government aircraft that dont wish their presence known to anyone that can afford the SBS receiver.

[clicker]

To quote the CAA website

"Within the UK FIR, Mode S Enhanced (EHS) has been mandatory for all aircraft flying IFR as GAT within notified Mode S airspace since 31 Mar 05 (with a 2-year transition period until 31 March 2007), as per AIC 49/2005 (YLO 171). It is now proposed to mandate carriage of a Mode S Elementary (ELS) transponder within remaining UK airspace by 31 Mar 2008. It is likely that there will be a 2-year transition period until 31 March 2010, to allow for any implementation difficulties. A Regulatory Impact Assessment (RIA) for the Mode S ELS proposal will be launched shortly."

However not all mode S transponders are the same, some give positional data, others don't. The UK military aircraft currently fitted don't and I would not expect them too either.

[BDiONU]

Is mode S going to be compulsary for all aircraft ? and if so what exemptions are there likely to be, for the likes of military and government aircraft that dont wish their presence known to anyone that can afford the SBS receiver.
Con Ops for Mode S in Europe have not yet been written. We do expect that some 20% of aircraft will be applying for various forms of exemption. This does, of course, include the military.

BD

[A7700]

Con Ops for Mode S in Europe have not yet been written. We do expect that some 20% of aircraft will be applying for various forms of exemption. This does, of course, include the military.
BD
What is happening in Europe and already in force :
http://www.eurocontrol.int/msa/public/standard_page/modes_docs_aics_aics.html#state
A mode S transponder is already mandatory if you need your T-CAS working...
and Major airports in Europe are installing Mode S multilateration system to track and identify traffic onthe ground.

[BDiONU]

What is happening in Europe and already in force :
http://www.eurocontrol.int/msa/public/standard_page/modes_docs_aics_aics.html#state
A mode S transponder is already mandatory if you need your T-CAS working...
and Major airports in Europe are installing Mode S multilateration system to track and identify traffic onthe ground.
But its all bits & pieces and note the dates on the information. There is still no joined up plan for Europe and certainly not one for the UK yet.

BD

[Radarspod]

Just to clarify a bit:

Mode S transponders are required for those aircraft that have to meet TCAS mandates, and anyone flying in the London TMA.

The best source of official info is in the relevant AICs:
AIC 49/2005 (Yellow 171) – SSR Mode S transition arrangements
AIC 105/2004 (Yellow 155) – Secondary Surveillance Radar (Mode S)

I'd expect the Mode S requirement to be extended to other areas outside of the TMA fairly soon.

With regard to broadcasting positional information, this requires a Mode S transponder with ADS-B capability, and is not mandatory. Something like the SBS equipment (which is technically illegal to use by Joe Public) can only use the ADS-B position reports. It cannot determine positions from normal Mode S surveillance replies to ground radars.

[Minesapint]

A mode S concept of ops is in the making. Its no easy task as it must take into account plans for Mode S ground surveillance at airports as well as Mode A and S 'mixed' operations. then there is the flagging of IFPS flight plans where the aircrfat is equipped and the flight is within contiguous Mode S airspace (/modesasp) - phew! How to ensure that a flight is activated by radar on departure if the downlinked Mode S identity is not correct is one question doing the rounds in Europe.

The transponders themselves have "issues" too. One type switches to standby in certain circumstances, one squawks 0607 for no apparent reason, one creates a ghost track 9.25Nm on the beam - there are others!

Mode S has a number of problems to overcome before it replaces Mode A, no matter how hard ICAO, Eurocontrol and the regulators push/

[Turn It Off]

So if Aircraft are being forced to carry Mode S are ATSU's going to be forced to be able to interrogate MODE S information?

TIO

[BDiONU]

So if Aircraft are being forced to carry Mode S are ATSU's going to be forced to be able to interrogate MODE S information?
TIO
Kinda chicken and egg :ooh: Although it would seem to make more sense to me to have aircraft on Mode S first so that ATC aren't spending a fortune on technology which is not going to be of use for several years. I know the opposite applies as well but a transponder is considerably cheaper than a radar head and all the downstream software!

BD

[Denti]

Over here (germany) its a bit more mixed, they distinguish between new and all aircraft (all meaning that all have to be retrofitted) and ifr and vfr.

since march 31st 2004 new aircraft flying ifr have to have mode s equipped, the retrofit period is 3 years so that all aircraft flying ifr have to have mode by march 31st 2007.

VFR aircraft flying in airspaces C and D (D not ctr) and transponder mandatory zones have to be equipped with mode s since march 31st 2005 if new and retrofits have to be installed til march 31st 2008.

There are a few more restrictions. All aircrafts that had to be equipped with Mode A/C (that includes Ultralight aircraft if they fly within TMZs or airspace D) need to either retrofit or have Mode S since factory, required is Mode S elementary surveillance if the max TOW isn't above 5.7t or the max true air speed in cruise isn't above 250kts, all aircrafts exceeding those values need Mode S enhanced surveillance. If you're required to have enhanced surveillance installed your aircraft/transponder system needs to be able to report in addition to the normal enhanced surveillance data

heading and speed report
track and turn report
selected vertical intention


Of course you can allways try to get an excemption, and i would think that state aircraft (including military) will be excempted to most of that as usual.

As far as i know only radar stations around FRA and MUC are equipped with Mode S so that all the nice and shiny new transponders are largely unused.

[Minesapint]

In short, if you want to fly in UK controlled airspace you will require a Mode S transponder.

Mode S Elementary Surveillance (ELS) Implementation Timescales

IFR Airborne Implementation

For aircraft flying IFR as General Air Traffic (GAT), the latest dates for the carriage and operation of Mode S ELS airborne equipment in designated airspace are as follows

New production aircraft to be compliant by 31 March 2007.
Completion of aircraft retrofits by 31 March 2007.


VFR Airborne Implementation

All aircraft flying VFR in designated airspace are required to carry and operate Mode S ELS airborne equipment by 31 March 2005 with the following Transition Period:

New production aircraft to be compliant by 31 March 2005, although there is now a general relaxation until 31 March 2008.
Completion of retrofits, irrespective of date of first CoA issue, by 31 March 2008.

http://www.eurocontrol.int/msa/public/standard_page/modes_homepage.html

[Radarspod]

Kinda chicken and egg :ooh: Although it would seem to make more sense to me to have aircraft on Mode S first so that ATC aren't spending a fortune on technology which is not going to be of use for several years. I know the opposite applies as well but a transponder is considerably cheaper than a radar head and all the downstream software!
BD

From the groundstation side, the CAA won't renew any non mode S licences to operate beyond 2012, so within 5 years all the ground side should be Mode S capable anyway. :ugh:

[robin]

.. but for aircraft in the ELS category outside designated airspace, there is a notional implementation date of around 2010 (always assuming that the forthcoming RIA, starting next month and the delivery of a cost-effective LAST can be achieved)

[Pierre Argh]

military and government aircraft that dont wish their presence known for that, they can always switch to O.F.F. mode... providing the flight is conducted iaw appropriate regulations and clearances

[threemiles]

As far as i know only radar stations around FRA and MUC are equipped with Mode S so that all the nice and shiny new transponders are largely unused.

All radar sites are under implementation of Mode-S as these are not only used by the terminal ATC, but also by Maastricht etc. Implementation is planned to end late 2006.

[Minesapint]

What are the plans for UK airports? For 'real' contiguous Mode S airspace we require Mode S ground surveillance equipment to validate the Mode S flight identity prior to departure.

[Radarspod]

Only know of NATS ones, all NATS owned SSR will be Mode S by 2012.......if the other operators don't do the same, they wont be able to operate Mode A/C only as they will have no licence!:=

[NorthSouth]

Just to clarify:
1) can the current Mode S SSRs in the UK (the new NATS en route radars for example) also interrogate (and understand the replies from) Mode A/C transponders?
2) if the answer to that is yes, is there some equipment in these radars that will simply be switched off on the mandatory Mode S implementation date?
3) are current TCAS designs activated by both Mode A/C and Mode S transponders?
4) assuming the answer to that is yes, will all TCASs be altered from the mandatory Mode S implementation date so that they only respond to Mode S transmissions?

NS

[BDiONU]

Just to clarify:
1) can the current Mode S SSRs in the UK (the new NATS en route radars for example) also interrogate (and understand the replies from) Mode A/C transponders?
Yes.
2) if the answer to that is yes, is there some equipment in these radars that will simply be switched off on the mandatory Mode S implementation date?
No because some aircraft will be exempt from carriage of mode S transponders. Current estimate is about 15-25% of all aircraft.

3) are current TCAS designs activated by both Mode A/C and Mode S transponders?
Assume so but I'm ATC systems not aircraft systems.
4) assuming the answer to that is yes, will all TCASs be altered from the mandatory Mode S implementation date so that they only respond to Mode S transmissions?
I would assume no, see answer to 2.

BD

[NorthSouth]

No because some aircraft will be exempt from carriage of mode S transponders.Very interesting. So there will be two categories of non-Mode S aircraft from 31-3-08: those that still have an SSR response because they're transmitting Mode A/C, and those that have no transponder at all.
So what's the problem with allowing some aircraft to carry on with Mode C, as an exemption to the mandatory Mode S requirement? Surely it's better than an exemption which allows an aircraft to have no transponder at all?
NS

[BDiONU]

Very interesting. So there will be two categories of non-Mode S aircraft from 31-3-08: those that still have an SSR response because they're transmitting Mode A/C, and those that have no transponder at all.
Correct.
So what's the problem with allowing some aircraft to carry on with Mode C, as an exemption to the mandatory Mode S requirement? Surely it's better than an exemption which allows an aircraft to have no transponder at all?

Because the rules, which have been decided by the EU, state that if you have a transponder which is not going to be mode S after the implementation date mean you have to apply for an exemption. Personally I don't see a problem with non transponder equipped aircraft and those with yea olde Mode A/C. Except if you want to fly in airspace where the carriage of a suitable transponder is a mandatory requirement :) Then you're going to have to have an exemption :ok:

BD

[PH-UKU]

Certainly not the VFR pilot struggling to meet current high bills and over legislation. :*

I currently operate out of Class D. I don't have a transponder. It has never been a problem for ATC - who are fantastically helpful by the way. I am operating VFR in Class D for perhaps 5 minutes until I get out into the open FIR where I then 'see and avoid' and don't speak to any ATC provider - cos there is no radar or radio cover in the mountains.

I think we (or rather the desk pushers who make the rules) have a real tendency in the UK to try to over control VFR traffic, and this (Mode S) will just make it much much worse. Perhaps a sad reflection of the fact that so few ATCOs (or pen pushers) actually fly or understand that there is a huge amount of legitimate aviation outside of the sacred lo-costs ? Witness the large amount of mixed GA successfully integrated with big jets all over the USA imagine that in the UK ...

But back to Mode S ..... I've seen the cluttered radar displays all around the UK, particularly in local areas and mil training areas. Look at the displays at Scottish Centre - tiny 20 inch screens for 150-250 mile sectors - every SSR label is about 15 (yes 15) miles across.

Imagine if EVERY flying machine now has to squawk. Every glider, microlight, balloon or binbag. You are going to be faced with one glowing cluttered screen. And before someone says that you can height filter out ... not if you are operating below FL100 or outside Controlled Airspace as standard.

But the real issue is that I am expected to pay for someone elses supposed commercial gain. If it costs me or my company a (compulsory) £3000-£3500 to buy fit and test for each aircraft, who will compensate me for my loss ? What benefit is there to me ? I really would like to know. Rachael Reid (Corporate Comms) of NATS at one meeting said NATS might pay for fitting Mode S ... I'll believe it when I see it.

If someone forces me out of my house to build a new road (for other peoples benefit), I would be compensated, and rightly so.

Now, perhaps the one advantage in mode S I can see would be if the fast pointy jets were also fitted with compulsory ACAS/TCAS to see other traffic. But they won't be. If you look at the Big Bumper Book of Airmisses, you will see fast.pointys feature very very highly - rough check about 40%. That tells me there IS a problem with military jets seeing and avoiding other users.

[BDiONU]

Imagine if EVERY flying machine now has to squawk. Every glider, microlight, balloon or binbag.
Excellent idea and one which the EU seem to be striving for as industry are developing a low cost, lightweight transponder. You could almost (if they were identified by ATC) have a totally known traffic environment
Now, perhaps the one advantage in mode S I can see would be if the fast pointy jets were also fitted with compulsory ACAS/TCAS to see other traffic. But they won't be.
Correct. We reckon the largest appications for exemption from mode S will be from the military. You almost have to laugh because the eurofighter, latest addition to the European military fleet, is not even 8.33Mhz capable!

BD

[Minesapint]

NorthSouth, take a look at the link I posted above to the Eurocontrol site. There is lots of info there, including on TCAS and TCAS2. Mode S radar's allow the downlinking of the flight identity and recognise mode A returns, there will be no need to turn anything off and mode A/C will be around for many years.

The RIA is out for review, have you seen it?

[PH-UKU]

Quote:
Originally Posted by PH-UKU
Imagine if EVERY flying machine now has to squawk. Every glider, microlight, balloon or binbag.

BDiONU wrote in reply
Excellent idea and one which the EU seem to be striving for as industry are developing a low cost, lightweight transponder. You could almost (if they were identified by ATC) have a totally known traffic environment

BDi
"Excellent idea" ? You have taken my point out of context. Do you REALLY believe that ? If so then I think you are too much of a control freak :}

Military traffic being exempted removes any likelihood of a known traffic environment. And anyway, it may be sensible around busy airports, but in the highlands and islands, what use is Mode S when you get no radio or radar cover amongst the mountains anyway ?

And another thing :hmm: it is difficult enough getting LARS (even if we could get it in Scotland) when the controller is busy. Imagine how much busier you will be if everyone who has to carry Mode S decides to call you up ... and believe me they will (if only to prove the point). Beware creating a rod for your own backs and over-controlling .......... :=

We should all remember that basically EVERYONE has an equal right to use airspace. Whether that be military, commercial ops, pissed punters going to Spain, flying training, gliding, micro-lighting or recreational. The way things are going it seems that 'recreational' is considered by some (in the CAA and NATS) to be dispensable and a nuisance. It is a sad attitude and reflects a woeful appreciation of the full gamut of aviation activities in the UK.

Just because someone is flying for recreation, shouldn't mean they get disregarded.

[BDiONU]

BDi
"Excellent idea" ? You have taken my point out of context. Do you REALLY believe that ? If so then I think you are too much of a control freak :}
As an ex military controller I'd much rather know what the blip flying around the area I'm giving a service in is, even if only an unverified squawk.
Military traffic being exempted removes any likelihood of a known traffic environment.
But the military do have transponders and they do squawk when flying low level (7001).
And anyway, it may be sensible around busy airports, but in the highlands and islands, what use is Mode S when you get no radio or radar cover amongst the mountains anyway ?
ADS-B :)
We should all remember that basically EVERYONE has an equal right to use airspace. <snip> The way things are going it seems that 'recreational' is considered by some (in the CAA and NATS) to be dispensable and a nuisance. It is a sad attitude and reflects a woeful appreciation of the full gamut of aviation activities in the UK.
Just because someone is flying for recreation, shouldn't mean they get disregarded.
I would disagree, the UK's DAP (Directorate of Airspace Policy) are very mindful of the GA fraternity IMHO of course :)

BD

[London Mil]

You almost have to laugh because the eurofighter, latest addition to the European military fleet, is not even 8.33Mhz capable!

BDIONU, is that something like 8.33 kHz spacing? :p

Furthermore, I wasn't aware that 8.33 had expanded into the UHF band.:ok:

[BDiONU]

BDIONU, is that something like 8.33 kHz spacing? :p
Furthermore, I wasn't aware that 8.33 had expanded into the UHF band.:ok:
8.33 spacing, apologies for the smelling pistake :)

BD