Mode S. Pipe dream or practical unit?

[blue up]

I recall a couple of years ago, at a UK CAA safety evening, some chap from the ministry (ex RN helo driver?) telling us that the L.A.S.T. transponder was soon going to be here at a projected £250. Now, having no electrics on my wooden aeroplane I was keen on getting a battery power unit with enough oomph to paint me on every radar within miles.

Has anyone got a believeable update on the efficacy of the current crop of Mode S transponders with regards to range, power output, radiation effects, weight and price?

I visited the approach control at a Major UK international airfield (well, Cardiff) and was interested to note that they didn't have mode S info displayed (or maybe not displayable?) Is it ready to roll out or is they system slipping behind schedule?

Does it work? Will it work? Can I afford it? Can I not afford it? Do I need to get some lead-lined underpants?

I'm sure the info is "out there" somewhere but a lot seems to be either out of date or a bit 'sensationalist'.

[IO540]

There is no prospect of a "cheap" transponder until Mode S is mandatory for all traffic, and this is obviously not going to happen for many years, if ever.

I don't know why the CAA was claiming there would be one - such a claim (which I heard too, in their conferences etc) was never going to happen. It made no commercial sense because none of the existing manufacturers is going to bomb the market price and cut their own throats, and no newcomer is going to get aggressive until the much enlarged market is assured.

Most European airports don't have Mode S and won't for years.

The radiation from any transponder is very low because it is in very short bursts.

[Rod1]

The original CAA sponsored low power mode s transponder is a dead duck. Trials showed significant problems and it did not comply with international standards. The CAA has categorically stated it will not mandate mode s for all aircraft due to the insurmountable technical problems in getting something to work, and not braking rules such as minimum empty weight (critical for micros).

If you want a protable mode s unit which works the only one I know of is;

TRT 800A Mode S Transponder at £1729 inc vat

GS 7 Mobile Housing For TRT 800 at £403 inc vat

This is not a light weight solution!

Rod1

[jxk]

Put it in a pipe and dream.

[vee-tail-1]

From this and other threads :confused:

Mode S & TCAS won't work for GA. Not enough aircraft fitting the transponders, and even if they did, not enough ATC units able to receive mode S.

Ballistic parachutes can not be used at low level where most risk of midairs occurs.(Manoevering at airports, OHJs, mixing VFR with IFR etc)

See & Avoid is less than 50% effective even in perfect conditions when you know the traffic is there.

So what else can we do to minimise the risk of a midair? Would the fitting of VERY big and bright alternate flashing strobe lights be cost effective, or useless?

Flying is not without risk, perhaps we should just accept that fact and consider the effects of our accidental deaths on our families.:(

[chrisN]

Rod wrote [snip] TRT 800A Mode S Transponder at £1729 inc vat

GS 7 Mobile Housing For TRT 800 at £403 inc vat

Rod, Hi. What about the aerial - does the unit include it or do you need a stick-on or something? And what about the battery to drive it?

Chris N.

OK, found the answer:

GS 7 Mobile Housing For TRT 600 / 800
With rechargable battery. Add the price of the transponder to get the complete price. Charger extra. Antenna fitted to top of unit is included. Available only when ordered with a transponder and not on its own; this is for certification and warranty reasons.

CN

[blue up]

I guess that the £2500 price still stands after you add VAT, fitting and a short man from the ministry coming over to sign your piece of paper.

I've had a go at a Red Arrows type smoke generator on my Healey. Injects dirty diesel into the exhaust pipe about 10 inches below the exhaust valve. Makes a lovely puff of smoke. I noticed the Arrows dropping puffs as they turned base leg. Makes them quite visible. Probably better than Mode S, anyway.

Any ideas on the current/wattage of the current Mode S systems? Are we talking AA batteries or a fat one from a burglar alarm?

Are new Mode A/C fitments banned in the UK? I recall hearing something to that effect. Seemed a little.....y'know.....unwise to stop adding them especially as they've become so cheap on the secondhand market.:rolleyes:

[gasax]

Strobes help - particularly the double or more flash units. But when the ambient light levels are high they are much less visible.

If Mode S came with TIS then I would buy a set this year. At the moment it adds nothing to my Mode C and so is a complete waste of money.

2 years ago Kinetic announced their LAST unit complete with a price tag. Since then I can only suppose they have either proved it does not work, or it is not cost effective for them to tool up (of hire a sub-contractor to do this) to produce the unit.

I also remember that the CAA were touting a 'strobe detection' device which IIRC was being developed by Quiniteq. Strangely (or not perhaps?) I've heard nothing more in recent years.

[RatherBeFlying]

The European glider community along with many helicopters and g/a has gone over to FLARM; there's 11,000 units installed.

576 Euros, low weight, low power and includes obstacle database.

The real problem is the aviation authorities who are doing their best to hang on to horse and buggy technology -- transponders and TCAS:}

[Steve N]

Flarm doesn't trigger SSR or TCAS only another Flarm. There is no UK terrain database I could find. Mainly used and very useful around the Alps as I understand. Our local gliding club told me few in their members planned to fit it. I know one UK non gliding related GA aircraft fitting one and he was given it. ADS-B does what Flarm does and works without a ground station in range. It is the way forward. Ask the FAA.

My 2p

Steve

[Radarspod]

Rod1,

When you say "portable Mode S unit", in what way? Mode S transponders have to be set up with the Mode S aircraft address of the airframe they are attached to. Is this being used by more than one aircraft, or just portable as in not permanently installed?

As an aside, you may be interested in this Safety Notice on the TRT800, http://www.easa.europa.eu/ws_prod/c/doc/Safety_Info_Reports/SIB%202008-72R1%20Funkwerk%20(Filser)%20TRT-800A%20Transponders.pdf

RS

[Rod1]

“Mode S transponders have to be set up with the Mode S aircraft address”

Correct! However most of the low cost units have the facility to enter the code from the front panel and some will allow more than one to be stored.

I am not selling the TRT800, I was just answering the portable question.

Rod1

[gpn01]

Hi Radarspod, useful link. Makes for interesting reading, particularly:

"flight trials have shown that the unit fails to perform as expected, particularly when operated in areas with high SSR interrogation rates."

Wonder if that's being experienced by other Mode-S devices ?

[chrisN]

Blue up, information I have seen is that typical current usage of modern solid state Mode S transponders (Filser, Garrecht etc.) is about 1 A or less. A 7-AH battery should give 4-6 hours use before the voltage drops too much, at low altitudes/normal temperatures. Less when high/cold. Less if lots of interrogations, presumably. (All second hand from others, no personal experience.)

Older types, using a heated altitude encoder thingy, presumably use lots more juice, and Mode C squitters much more often that Mode S – I am told.

If this is wrong, no doubt an expert will soon be along to correct it.

Chris N.

PS – there is a picture of the Filser “portable” with antenna and battery etc. at Mode S Transponders from LX avionics Ltd (http://www.lxavionics.co.uk/transponders.htm) . I would not fancy carrying that in my glider cockpit with me.

[Crash one]

Is it possible to buy a mode C tx new or have all manufacturers stopped building A/C only, as mode S includes everything?
I am not tx equipped & sometimes feel like I need it.

[gasax]

After 31st March 2008 it is no longer possible to legally fit a Mode a/c transponder to a G reg machine. So it's Mode S or nothing.....

This was part of the 'consultation process' - which I don't much remember being mentioned. There is a 4 year transition period for aircraft already equipped with a mode a/c.

[Rod1]

“After 31st March 2008 it is no longer possible to legally fit a Mode a/c transponder to a G reg machine. So it's Mode S or nothing.....”

This info is out of date. It is still possible to fit mode c to G reg aircraft. Mode c units are still made and second hand ones are available.

Rod1

[gasax]

I'd appreciate a reference to support that Rod, I looked up the official statement on the CAA website, mainly because I was flying with a firend last weekend who wanted to fit a secondhand mode c unit. My post is a near exact quote from them so if it is possible how?

[bambuko]

exemption permitting mode A with mode C ... until 31 March 2012, applies only if the aircraft was so equipped prior to 31st March 2008
I take it, that this means you are not allowed to fit mode C as a new installation now.
refer:
http://www.caa.co.uk/default.aspx?catid=810&pagetype=90&pageid=9320

Chris

[Crash one]

I just looked at the CAA site ref; Mode S. If you go through the "interactive guide" thing "below FL100, outside CAS, International FIS boundaries, Mandatory zones, blah blah" Mode S not required but highly recomended. No gaurantee that Mode C will be allowed after 2012."
I can't find where it says "not allowed to fit one if none is fitted at present".

[Rod1]

gasax

Full info was on the LAA site a few months ago (not checked since). The situation was stated at the last mode s meeting at LAA HQ and the CAA were advised that some offices were not accepting new aircraft with mode c, by the LAA.

Rod1

[Dont Hang Up]

The CAA policy on Mode S transponder fit is best summarised as follows:

When operating in airpsace or under any air traffic service where transponder equippage is required, then Mode S SHALL be the means of compliance.

These are my words rather than a direct quote, but are clearer than the AIC and I assure you that this is precisley the emphasis that the CAA intend with their current mandate.

What this does not preclude is the fitting or continued use of Mode A/C purely for purposes of conspicuity (both to ATC and TCAS). Whether you can continue to buy non-Mode S kit is another matter.

[gasax]

This is a copy of the CAA stuff;

Phase 1 of the CAA’s phased approach for the further carriage of Mode S requires that Mode S transponders replace the use of Mode A/C in all circumstances where transponders are currently mandatory. This proposal was considered to be the minimum next step that should be taken towards the phasing out the use of conventional Mode A/C SSR in UK airspace. This proposal was submitted to and subsequently accepted by the Secretary of State for Transport, and thus enters into force in the Air Navigation Order (ANO) from 31 March 2008.

This measure does NOT affect the voluntary carriage of transponders.

A transition period until 31 March 2012 is being provided to permit time for owners of affected aircraft currently equipped with Mode A/C transponders to have them upgraded to Mode S.

Owners and operators of Mode A/C transponder equipped aircraft are exempted from the ANO until 31 March 2012 by the General Exemption, Official Record Series 4 No. 670.

The exemption only applies if:

the aircraft is equipped with SSR equipment, installed on or before 31 March 2008, which includes pressure altitude reporting capable of operating in Mode A & Mode C and capable of being operated in accordance with such instructions as may be given to the aircraft by the ATC unit;
the aircraft is not operating under IFR within EHS airspace; and
written notice of the aircraft registration and aircraft serial number has been given to the CAA.

Ahhh!

This set of statements does not apply to the VOLUNTARY carriage of transponders - so if there is not a compulsory requirement to carry Mode S then none of the above is applicable.... because it applies to the transition arrangements of compulsory transponder carriage!

As usual with this whole debacle the CAa being less than straight forward (or even honest and transparent!).

Rod I've had a browse through the LAA site and not been able to find the applicable guidance. I'll drop John Brady a note to see if he can post something suitable.

Many thanks for the help!

[jabberwok]

2 years ago Kinetic announced their LAST unit complete with a price tag. Since then I can only suppose they have either proved it does not work, or it is not cost effective for them to tool up (of hire a sub-contractor to do this) to produce the unit.

I suspect you are right. I was hopeful this unit would be on sale last year but the last news from Kinetic said it was going through the certification stage. Since then there's been no update and I doubt it would take over a year for this process.

I understand that Mode C is now prohibited in Dutch airspace?

[gasax]

There are some threads on the Flyer site re Mode S applicability over the channel. My understanding is that above 1200 ' Mode S is required and in the designated TMZ areas, which do cover quite an area. The Dutch seem to be further along with the process than any of the other Europeans.

[Rod1]

gasax

Your statement;

Ahhh!

This set of statements does not apply to the VOLUNTARY carriage of transponders - so if there is not a compulsory requirement to carry Mode S then none of the above is applicable.... because it applies to the transition arrangements of compulsory transponder carriage!

Is correct. However remember most transponders on VFR aircraft fall into the voluntary bracket now the CAA has backtracked on the compulsory mode s for all nonsense. Mode C is also very useful in France and as second hand units are very inexpensive, with no fitting costs on LAA aircraft this is a solution which is quite popular.

Rod1

[Crash one]

So it seems I can legally fit a second hand mode C unit to my Emeraude that doesn't have one at all & never has for it's 50 yrs. But no body is building new mode C units anymore?

[gasax]

I believe all of the US manufacturers will still supply new Mode a/c sets and there is still a stock of mode a/c sets from even the european manufacturers.

And as Rod says thanks to the various regulatory authorities there are a lot of secondhand sets available (I fitted a mode c unit I bought from the RSA website last year - 400 Euro complete).

[Rod1]

You can still buy a B/K KT76A Mode A/C unit from HM for 1051 inc vat. You would be mad to do it with second hand units around for £2 – 300.

I have Mode C, and will put off mode s for as long as possible. The regulator has a three phase plan. Phase Three is ADS-B, and I may save big money by fitting a second hand mode s, or going straight for an integrated, approved ADS-B with GPS unit (which will probably also be mode s compatible).

Rod1

[chrisN]

Rod, see your pm's. Regards - Chris N.

[Jodelman]

I have been told that it is impossible to purchase a Mode S transponder!!

All that are available are combined Mode A/C/S. A solely Mode S would sit under the panel or in some obscure place in the aircraft as it would not be necessary to touch it and would presumably be cheaper. The sqawk codes are obsolete with Mode S.

Is this correct?

[CJ Driver]

Jodelman - I think you are confused. All Mode S transponders are required to reply to legacy Mode A/C interrogations, so obviously any "Mode S" transponder is really Mode A/C/S. Hence, to put Mode S into an aircraft that has a Mode A/C transponder, you remove the Mode A/C transponder and replace it with a Mode A/C/S unit.

Also, the squawk code is alive and well with Mode S. It still forms a primary part of the identification of the aircraft, along with the callsign (Flight ID), and is required anyway for interworking with Mode A/C interrogators.

[gasax]

I've revived this thread as I have an answer from John Brady of the LAA on CAA 'policy' on voluntary fitment of transponders

"the CAA have confirmed you can fit an A/C transponder without restriction as long as you don't try to fly in airspace where mode S is mandatory (Airways and IFR in the London TMA). "

So much of the official output is almost misleading. Given the present low cost of Mode C units it would be well worth getting hold of one and fitting it!