Mooney_Driver wrote:
That is all TCAS does as well btw, it gives a VERTICAL resolution Advisory.
TCAS does a lot more. It has a situation display that shows the traffic in relation to yourself, and it uses azimuth, distance, speed, altitude and rate of climb to figure out whether to give an advisory or not.
The advisories are then vertical only, but the TCAS are talking to each other (if so equipped) to make sure they issue advisories in opposite directions. That is why the rule is that you follow the RA, even if ATC gives you opposite direction instructions.
The best reason I have heard WHY they only give vertical advisories is that – assuming perfect altitude keeping – any horizontal advisory would still have the aircraft track lines cross each other and the course correction required to achieve good separation is quite large, and track measurement is imprecise compared to altimetry, while vertically 500ft from each aircraft can give you 1,000ft vertical separation.
Mooney_Driver wrote:
That is all TCAS does as well btw, it gives a VERTICAL resolution Advisory.
But that is not because the TCAS unit does not know the azimuth (it does) but because the fastest way for an aircraft to get out of harm’s way is to change altitude.
It was planned to include horizontal resolution advisories in the TCAS III specification, which was then revised to TCAS IV and then abandoned altogether in favour of ADS-B.
Peter wrote:
There is no need to force GA to spend 4 figures on ADS-B
You don’t have to spend 4 figures on ADS-B. The low cost ADS-B devices being trialled in the UK are well under 4 figures and don’t need the expense of a certified installation (and even renters can use them as they are portable).
Transponder emissions aren’t very useful to other GA aircraft, it’s very expensive to be able to fit something that can display where a transponder equipped aircraft without ADS-B is flying (as you know, having installed such a box yourself). ADS-B on the other hand can be received with an rtl-sdr costing about £10 (maybe you’ll get up to £50 once you’ve added all the stuff to interface it to your tablet and SkyDemon).
Mooney_Driver wrote:
I have been advocating to have transponders mandiatory for ALL traffic in the air for years, but I get screamed into the ground and even threatened in other forums for suggesting this, particularly the glider scene states that it would be the end of their operations. I don’t believe that, I rather think that there is a old grudge and fear of transponders because quite a few of these guys fly illegally in CAS all the time.
That’s a hell of an accusation. I’ve been to a number of UK glider clubs and US ones, and any of them anywhere near CAS are at great pains to make sure you understand where the CAS is, how to avoid it, why it should be avoided – before they will let you fly from their site. No wonder you’re being chased off other sites if you’re making those kind of groundless accusations! Our club has NEVER had a CAS infringment. In fact the only CAS infringement that I know about from our airfield was committed by an airline pilot in a powered GA aircraft who should have known better! I know of no glider pilot who knowingly infringes CAS, and many glider pilots who are a great deal more aware of airmanship issues than the typical VFR burger run GA guy.
Transponders would indeed ground a lot of glider pilots: many aren’t well off (our tiny club has a couple of younger members who don’t make much above minimum wage, we have people in working class jobs etc). Many of the most flown airframes in glider clubs are old wooden gliders with a value of around £1500, they are EASA certified types so it would cost probably twice the airframe value to upgrade the electrical system and install a certified transponder – this all has to be done by an avionics shop since they are EASA types and the owner can’t just do it themselves and have a BGA inspector sign it off. Given that the risk of mid air collision is still very low (especially in the en-route phase) it seems grossly disproportionate your wish to either force either a completely inappropriate piece of avionics with a four figure installation cost, or grounding most of the gliding fleet – I’m surprised you’re suprised about being chased off other forums for suggesting a completely inappropriate technology, the rampant busting of CAS, and the wish to ground a large number of people!
To add to this transponders are the wrong technology for gliders. Most GA aircraft that flies in places where they could come into conflict with a glider don’t have anything on board that can even show that a transponder is nearby (let alone the direction and distance to the transponder). It’s very expensive to add something to a light aircraft that can show you where a transponder is: PowerFLARM is the most affordable option but it can only tell you that a transponder is near, not the range and direction – and if you’ve got PowerFLARM, you’re seeing a glider’s FLARM output anyway.
The low cost portable ADS-B devices the CAA are trialing are about a million times better to carry in a glider than a transponder. They require no certified installation, are self-powered, relatively inexpensive, and you can get something that will put the position of such an equipped aircraft on an iPad for around £50 rather than £5000.
This makes me think very much about whether I should really continue flying with a small daughter to take care of.
Without any offense, with such attitude you should definitely avoid entering the cockpit. If you’re overwhelmed with such feeling (and you expressed it on several occasions) then you pose a threat in cockpit. Risk awareness in one thing but being self-confident is necessary for exercising PIC privileges.
Regarding the topic, I didn’t understand whether both aircrafts were in VMC or one appeared from the clouds.
Leaving all the tech solutions aside for a moment. Here’s an alternative to the Mk I eyeball – the Mk II ears. Did these guys not talk to each other and/or broadcast position and intentions?
Our club has NEVER had a CAS infringment.
I am not for a moment suggesting you are wrong, but if you don’t have a transponder you will never get busted if you had 
And if like so many in the UK you fly Mode A only, you can fly through any CAS those base doesn’t touch the ground, too, and not get busted
You might just hit something very big and with lots of rivets 
Did these guys not talk to each other and/or broadcast position and intentions?
Often this is hard, if there is a lot of radio traffic. Also, many pilots broadcast their position incorrectly. Some are well known to do it intentionally to “get ahead” on e.g. a landing clearance
Transponder emissions aren’t very useful to other GA aircraft, it’s very expensive to be able to fit something that can display where a transponder equipped aircraft without ADS-B is flying (as you know, having installed such a box yourself).
As the owner of a Zaon XRX PCAS I‘d like to voice my disagreement. Unfortunately the boxes aren’t produced or developed any more, and on my last flight a week ago I discovered that the power plug broke again (having soldered it back in place about 2 years ago). But I happily flew/fly with this box and find it useful except in the traffic pattern, where this occurred. Two weeks ago we had a similar situation, traffic being called out by Friedrichshafen TWR on end of downwind while we were exactly there. Four eyes intensely looked outside and we never saw the traffic. I wonder if he was left downwind while we were right downwind.
As to this accident, when I read about it it immediately gave me a bad gut feeling and leaves me sad and puzzled.
Did these guys not talk to each other and/or broadcast position and intentions?
They did, from the AFIS agent of Speyer. But yes, the German Flugleiter system is clearly detrimental to safety as opposed to CTAF because it discourages pilots from sorting out such issues directly between each other.
ZAON’s bankrupcy tells me there is something deeply wrong with the whole business of electronic conspicuity (EC) acceptance, versus the often religious proponents of various systems in pilot forums, usually with one poster for every different system, and I suspect often pushed by pilots who almost never fly, other than very short local hops
A Mode C detector which gives you relative altitude and a rough azimuth is simply the most versatile device available, by a huge margin, because transponder adoption is orders of magnitude bigger than for any other EC device… Unless one wants to fly through glider sites all the time, in which case FLARM will work better (in some countries).
