Mode S Mar 08

[robin]

AC-DC

I think there are just too many a/c without electrical systems to make this an easy option.

As things are the CAA are suggesting that we should carry a Tx eventually, but they haven't mandated radio carriage nor TCAS

[FullyFlapped]

Why leave gliders aside ?

I've no desire to spoil anyone's fun and enjoyment, but unless gliders absolutely agree that they'll never fly in cloud then I reckon they - and everything else - should carry something which allows them to be pinged.

Can't be that difficult to produce a lightweight, battery powered unit even if it only has a fixed mode C ident (with GPS derived altitude) which means "I am a glider - and therefore highly likely to do something unpredictable" ...
OK, OK, I'm already out the door !

FF

[AC-DC]

If there will be something light enough then gliders should have it too. Too many 'near miss' or "oh, I did not see it, did you?".

[Fitter2]

Oddly enough, a majority of gliders (and helicopters) in Europe, and a rapidly increasing number in UK are equipping with an effective anti collision system called FLARM. www.flarm.com It also gives obstacle warning.

TCAS doesn't hack it for the mode of flight (in the Alps it would be continuously active and hence ineffective, or for the panel space/power considerations.

Of course, this is not compatible with the CAA's wish to equip all gliders with Mode S which will not give them collsion warning against the majority of their own risk, and is several times more expensive.

And when the USA shortly goes ADS-B, compatibility issues become even more questionable:

For general aviation aircraft the FAA has chosen a Universal Access Transceiver [UAT] surveillance link using 978 MHz in the DME band. UAT was developed in the USA specifically for ADS-B operation. (The Europeans seem to be favouring a third technology – there is no interoperability between the three technologies.)

In the light of all that, please convince me I should shell out for a Mode S transponder in my sailplane (where I don't have the panel space or spare battery capacity anyway).

[S-Works]

Much better idea, lets ground all the gliders instead. solves the entire problem.....

JOKE.......

[Rod1]

“I hope not. I hope that ALL flying machines will HAVE to have a transponder, mode C at least, then we will be able to have some sort of TCAS, and for those aircraft without electrical system it is not a bif deal to add one (leave gliders aside).”

That is the point the CAA started from, except they wanted gliders as well. After a huge effort on the part of the LAA and its allies we convinced them it was not technically feasible given current technology. This is now off the table, but may be revisited in the distant future.

Rod1
PS Bose, I have often thought that the ultimate in flight safety is ground everything. It would do wonders for the stats.

[Rod1]

An official CAA summary of the meeting on the 17th is now available on the LAA web site;

http://www.lightaircraftassociation.co.uk/index.html

It is more detailed than my summary, but otherwise very similar.

Rod1

[AC-DC]

There is also no doubt that you don't it for VFR scud running around Europe, and quite possibly won't need it for many years if ever.

By the way, I belive that the BENLUX and Germany demand mode S for all flights, VFR too.

That is the point the CAA started from, except they wanted gliders as well. After a huge effort on the part of the LAA and its allies we convinced them it was not technically feasible given current technology.

What is the problem to add a small air driven (by a prop) alternator to the wing or the aircraft's belly?

[LowNSlow]

AC-DC if the aircraft in question is operating under a CofA as my volts free Auster is until the next annual then you are looking at a time consuming and expensive Major Mod to be approved by the CAA. Off the top of my head I would say it would take a year and cost around 2,000 pounds. Add on the cost of the Mode S Transponder and you are looking at around 4-5,000 quid at today's prices. The current value of my aircraft is about 14,000. Do you see why I am reluctant to fit Mode S? This all changes when the Austers go onto a Permit to Fly later this year then the modification costs drop significantly but given that my flying is VFR only what benefit is Mode S going to give me? Will most of my fellow bimblers have fitted TCAS? I don't think so. I think I'll be fitting a Mode C transponder after I've fitted the electrical system then upgrade to Mode S in 2012 when (hopefully) there will be a low electrical demand, low cost unit available for us bimblers.

[Rod1]

“What is the problem to add a small air driven (by a prop) alternator to the wing or the aircraft's belly?”

I have a friend with a vintage machine who has this arrangement. The generator has made quite a difference to performance (85 hp 2 seater). He has it feeding direct or charging a battery when free. He can run his radio on it no problem, but the Transponder (with separate encoder) takes all the output and flattens the battery in about 2 hours. I do not have details of the generator, but Francis (from the LAA) was of the opinion it would not be suitable for most non electric LAA types.

Rod1

[AC-DC]

L&S and Rod1.

Thanks, I see your point.

[IO540]

I don't disagree with certification charges, but I don't see the battery life argument.

My GTX330 draws around 0.2A (actually measured current) at 24V. A sealed lead-acid battery (dirt cheap) weighing about 1kg would deliver this for a good number of hours, and would recharge overnight. A lithium polymer battery would do far better than that.

[gasax]

The GTX330 spec sheet states that it draws approximately 27W. So a bit more than measured. A 'standard' aircraft battery could do that for a while from a full charge - but of course is unable to withstand 'deep cycling' for any period for that you need a traction or 'leisure' rated battery, much heavier - a lightweight battery of most descriptions will struggle.

[IO540]

Gasax, you have the battery technology v. suitability wrong, but I don't suppose anybody cares.

Also, if an avionics item the size of a GTX330 actually dissipated 27 watts (and the radiated power is tiny because the duty cycle is tiny), without a fan, it would start smoking

[dublinpilot]

By the way, I belive that the BENLUX and Germany demand mode S for all flights, VFR too.

AC-DC,

Is this currently, or from March 08? I tried to look up the Belgian AIP on the Eurocontrol website, but it made no reference to transponders of any time in the mandatory equipment section. Obviously it wouldn't be there yet if it only applies from March 08.

Maybe I'll have to rule out that Oostende trip for a little while yet

dp

[Staggering]

According to the Garmin manual on their web site the GTX330 transmit power is 250 Watts nominal. That would make the current draw at 13.8V around 18 amps on transmit which it will do each time it is interrogated. I believe ERP is derived from antenna gain, not duty cycle.

[Rod1]

My mode c system uses about 3.5a.

Rod1

[AC-DC]

Is this currently, or from March 08?

Yes, this is the way I understood it.