Primarily for general aviation discussion, but other aviation topics are also welcome.
  • 1
  • 6
  • 7
  • 8
  • 9
  • 10
  • 19
#1828160
connone wrote:
I received my SkyEcho 2 on Saturday. SDA is set to 1 by default. This seems to follow an update in December 2020.

https://uavionix.com/support/skyecho/up ... -software/

I'm assuming that this setting has now been agreed and I can use the device with SDA=1.


UAvionix SE2 Installation and Pilot's Guide dated 17 Feb 21 still says (p11) In the UK, SDA=0 is required to be transmitted. :(


With SDA=0 , as the Installation and Pilot's Guide says we must in the UK, its transmissions are filtered out by certified equipment in aircraft and by ATC. I tested this yesterday. ATC couldn't see me on their million pound radar but could on FR24. While this is the case, it is essentially a toy, not a safety aid.

I bought it essentially for its fun value, so I'm not disturbed by this.
#1828162
xtophe wrote:
patowalker wrote:There is a note there which says: "United Kingdom: Set SDA to 0 (zero).The RTCA standards require SDA =1 before data can be presented to aircraft with certified ADS-B In systems."

@Cub , are you able to divulge anything on the progress of a CAP1391 v3 ?


I was last told that it was the intention to deliver the change, I.e. they agreed with the safety argument produced by CASA and uAvionix assisted them with reviewing some of the technical aspects. I understood the change was due around Christmas and will formally ask for an update.

I believe @G-BLEW is also pursuing some questions about this particular delay.

On the basis that Australia requires SDA = 1 and that SkyEcho conforms to that standard and that the CAA have indicated they intend to change CAP 1391 to allow SDA = 1, we have set the default on all SkyEchos shipped to SDA = 1. In the meantime, clear instructions for new purchasers in UK as to how to change that integrity value, should they feel the need to, are contained within the manual.
#1828165
we have set the default on all SkyEchos shipped to SDA = 1 and clear instructions for new purchasers in UK as to how to change that integrity value in the meantime, are contained within the manual.


Mine was delivered on Saturday. Where in the manual are these "clear instructions"? I've just checked and don't see them? (Serious question.)
#1828168
Cub wrote:[... to how to change that integrity value, should they feel the need to...

Why might they not feel the need to?

Are you saying that, despite what CAP1391 (Table 4 page 42 of latest edition April 2018) currently says (ie SDA is to be set to ZERO), SDA=1 is an acceptable setting for UK operators to retain?

In the absence of a change in policy from the CAA, surely SDA=1 from an SE2 in the UK today is not legal?
#1828170
The manual is at https://uavionix.com/downloads/skyecho/SkyEcho%202%20User%20and%20Installation%20Guide%20REV%20J.pdf

On page 11 we refer to SDA value requirements in each country;

SBAS GPS reception
o High precision SBAS GPS meeting performance requirements of TSO-C199, transmitting a Source Integrity Level (SIL) value of 1, ensuring ATC and airborne avionics can receive and trust the GPS position being transmitted.
o In the UK, SDA=0 is required to be transmitted
o In Australia, SDA=1 is required to be transmitted


On pages 19-21 we describe how to configure your device for the first time including how to set/change the SDA value.

If you need any more assistance or help just make a support request or PM me and we will gladly oblige.
#1828171
Dave W wrote:
Cub wrote:[... to how to change that integrity value, should they feel the need to...

Why might they not feel the need to?

Are you saying that, despite what CAP1391 (Table 4 page 42 of latest edition April 2018) currently says (ie SDA is to be set to ZERO), SDA=1 is an acceptable setting for UK operators to retain?

In the absence of a change in policy from the CAA, surely SDA=1 from an SE2 in the UK today is not legal?


Very good point, well made Dave. I was of course, referring to the ‘need’ to change the setting when transiting between the Australia and the UK rather than the necessity for customers in the UK to change the default value, pending a reissuing of CAP1391.
#1828174
I was confused but probably because my Google search for SkyEcho 2 manual brought up Rev H from the uavionics website, which doesn't provide any guidance on setting SDA - so I left the default setting. I now realise that guidance is on the later revisions. Not sure how I got an old version.

Thanks for pointing me in the right direction.
#1828179
Aeronca Alan wrote: I tested this yesterday. ATC couldn't see me on their million pound radar but could on FR24. While this is the case, it is essentially a toy, not a safety aid.


The safety bit comes from other (GA) aircraft being able to see you. As @xtophe says few civilian ATC units have ADSB-in yet, and in any case it's not intended as a substitute for a transponder. It's use by ATC is likely to come within ATZ's and possibly a new form of TMZ (as being trialled at Goodwood), i.e. forms of airspace within Class G. However at the moment those units cannot formally utilise ADSB based traffic information because the CAA have not yet issued a general authorisation (although you might find some airfields beginning with K or T already have informal access to this).

There is an issue at the moment with reception by some certified ADSB based traffic systems, which you're likely to find on commercial traffic - but as described this is (again) a CAA standards issue, not a technology one. Any ADSB-IN capable GA system will see you OK provided you are in range as they are not as "fussy" as certified systems.

You need to compare this to a Transponder, which will be seen by radar-equipped ATC (so not many of those at GA airfields), will be seen by TCAS equipped commercial traffic (not much of that in Class G), might be seen by PAW users (if they are in range of an ATOM GRID station), but will not be seen by a host of other GA users....... oh and costs 5-10x as much!
gaznav liked this
#1828198
Cub wrote:... the necessity for customers in the UK to change the default value, pending a reissuing of CAP1391.

Given that CAP1391 is not yet amended to allow SDA=1 transmission, and that it is not only the UK that doesn't allow that to be transmitted (e.g. the US don't either, according to the User Guide - it would appear to be only Australia that does), wouldn't it be more sensible for the default to be set to SDA=0 so that customers do not inadvertently transmit incorrectly/illegally?

After all, it's not as though the relevance of the SDA setting is particularly highlighted or otherwise obvious in the User Manual.

It previously defaulted to SDA=0 (and I have just checked that it wasn't amended on my ~2yo device by a recent firmware update: It wasn't ).

It does seem as though it isn't the best thing for uAvionix to do to anticipate a change to CAP1391 that is not yet in force.
johnm, Stu B liked this
  • 1
  • 6
  • 7
  • 8
  • 9
  • 10
  • 19