I don’t really care what SDA my SkyEcho ends up with really.
I’m doing two tests in a PA28 this afternoon. It has a Mode S transponder. I’ll be seen by ATC and other certified TCAS and TAS installations, and some other portable device users. I won’t see anyone.
I now take my SkyEcho with me. I can now additionally see a lot of other traffic and gliders and more other portable device users can see me. [other devices will have the same effect].
I’ve increased my overall capability and the overall risk to myself and airspace users around me has been decreased.
This isn’t about which device is the magic wonder vaccine; every device brought (of any type) decreases the community risk a bit and the overall effect aggregates. Tragically this week I’ve already spoken to two people who aren’t going to apply for the CAA rebate because they’re not sure what device to buy.
mooney75 wrote:
Personally, I’m very confident that the ship has sailed for ADS-B. Except for aircraft > 5,700 kg, almost nobody transmits it.
I disagree. As usual, the US is years ahead: „Why is the FAA transitioning away from radar and towards ADS-B technology?
ADS-B is an environmentally friendly technology that enhances safety and efficiency, and directly benefits pilots, controllers, airports, airlines, and the public. It forms the foundation for NextGen by moving from ground radar and navigational aids to precise tracking using satellite signals.“
ADS-B simply works better for the purpose than radar.
MattL wrote:
every device brought (of any type) decreases the community risk a bit and the overall effect aggregates.
In the first place every additional device you add to your cockpit actually distracts you from what you are supposed to do and this is looking out of the window. If you spend more time watching on the various devices trying to figure out if those two dots are actually one target showing slightly different positions via different technologies or really two targets than watching out, safety is significantly decreased.
Maximum theoretic impact of all of these devices is to reduce number of midair collisions to zero. Given todays number of midair collisions, one can easily see that even in perfect circumstances impact of these boxes outside traffic patterns is quite limited – and emotional reports of pilots how often such a device already saved their lives are grossly overstated. Yes, you see a lot of traffic you would not have been aware of – but that is in 99,x% of cases traffic you would not have hit anyways.
I’m not arguing against these technologies at all – I invested more than 20k myself to have a convenient solution in my panel – just against the “more is always better” notion brought up here.
SDA is not a paperwork exercise. SDA stands for System Design Assurance, i.e. to what level it is ensured that the design of the part will not fail (more or less). Even if the UK CAA allows Sky Echo to set SDA=1 by bending the rules, you still need SDA 2 or even 3 in most cases, depending on the application in the certified ADS-B In aircraft.
Do you have a reference, actual test info, etc?
It is always interesting when a new poster pops up from nowhere and hammers a single topic only. Usually these are CAA/NATS/ATC staff telling us nobody gets busted for infringements and the system is a perfect example of a Just Culture; one can always tell those because they post only on matters of pilot criminality and are completely uninterested in anything to do with aeroplanes or flying them 
References can start with FAA AC 20-165 (cf Ch.3, point 3.1) and Annex 10 to ICAO Convention, Volume 4, section 4.5.
Can you point to the text which states that no certified ADS-B IN (i.e. Garmin Avidyne L3 Honeywell, taking the GA context) displays SIL=1 emitters?
Did I say that?
Context is everything
Let me put this in simple terms: is there anybody with a certified ADS-B IN traffic display system who can confirm whether or not they can see the suitably configured SE2? If nobody comes out then I reckon it does not show, and that whole exercise is disingenuous, just like so much in this game.
mooney75 wrote:
SDA is not a paperwork exercise. SDA stands for System Design Assurance, i.e. to what level it is ensured that the design of the part will not fail (more or less).
So what then is the difference between the SIL and the SDA?
Perhaps for the benefit of us lesser mortals that have no understanding of such things as SE1, SE2, ADSB in /out, someone with the requisite knowledge could do a “table” of devices showing advantages/disadvantages and what the device will interact with. For example it appears from these pages that SkyDemon is perhaps the most widely used GPS in GA followed by ??. So any device that shows a traffic advisory indication needs to be able to interface with SD and others.
Hope that is clear enough and not too impertinent to ask.
