Verifying Mode S ES ADS-B Out transponder setup - Can PilotAware help?

[SteveHutt]

Thanks Brian.
SIL/SDA looking good. 

BTW, for those wondering, like I did, Lee advised me the rows with DIST-KM of 999.000 are Mode C/S (non-ADS-B) broadcasts detected by PAW.

Steve

[neilmurg]

BTW, for those wondering, Lee advised rows with DIST-KM of 999.000 are Mode C/S (non-ADS-B) broadcasts.

Thanks for that! was looking at that today and wondering how I was capturing a/c at 999km!

[Admin]

Thanks Brian.
SIL/SDA looking good. 

BTW, for those wondering, like I did, Lee advised me the rows with DIST-KM of 999.000 are Mode C/S (non-ADS-B) broadcasts detected by PAW.

Steve

Apologies, I will fix that, can be confusing
Any other feedback gratefully accepted
Thx
Lee

[Admin]

Just got this screen shot with the latest software.
Somhow did same attachment twice, cant work out how to remove!

Many thanks for posting this Brian

Thx
Lee

[neilmurg]

DIST-KM of 999.000 are Mode C/S (non-ADS-B) broadcasts detected by PAW

Apologies, I will fix that, can be confusing

Don't remove it! 'no fix, Mode C/S' maybe, with an option to email them an offer of a PilotAware 

[Admin]

I plan to replace 999 meaning unknown, with a '-'
Thx
Lee

[Moffrestorer]

I do not have a handle on the precise reasoning for both SIL=0 and SDA=0 being requirements for uncert GPS ADS-B Out. I am trying to find out. I understand that CAT TCAS will ignore traffic broadcasting SIL=0/SDA=0. I don't know whether CAT TCAS will respond differently to SIL=0/SDA=2 traffic broadcasts.

Steve,

I emailed Ade Price at NATS (who was administering volunteers for their uncertified GPS trial) and posed your question to him how airborne or ground based systems might treat aircraft differently that broadcast SIL=0 and an SDA =0 or an SDA=2?

He replied "It would probably make no difference to the ground receivers if you had SIL 0 and SDA 2 but there will be a difference to some airborne equipment. Aircraft Surveillance Applications (ASA) that are compliant with TSO-C195B will display a target with SDA 1 or higher but will not show a target with SDA 0.

This means the permissible SIL and SDA values for non-certified GPS sources  prevent that data from being used on approved Cockpit Display of Traffic Information (CDTI) devices. I would not be surprised if you found this situation bizarre, particularly because EASA have approved the installation of PowerFLARM in AC23 type aircraft and PowerFLARM does not have a certified GPS source.

IMHO if you are not required to have a TSO-C195B compliant device installed in your aircraft, then you are free to use equipment that may not be approved to display ADS-B targets with non-certified GPS sources."

I'm not sure what CDTI devices are, and whether the definition includes TCAS. I googled "AC23 aircraft", and at this late hour, I was none wiser!

BTW, Ade also said it's a shame that Becker have not set the SDA to zero but perhaps they can be prevailed upon to change their data output. I have a feeling I've read somewhere that its pretty widespread practice across parts of mainland Europe (particularly amongst glider pilots) to connect uncertified GPS to their transponders. If this is true it could provide a basis, together with the NATS and LAA MOD 14 requirement, to request Becker to do just that! (Unless of course they have a vested interest in CDTI devices.)

Rgds,

Chris

[IainM]

This means the permissible SIL and SDA values for non-certified GPS sources  prevent that data from being used on approved Cockpit Display of Traffic Information (CDTI) devices. I would not be surprised if you found this situation bizarre, particularly because EASA have approved the installation of PowerFLARM in AC23 type aircraft and PowerFLARM does not have a certified GPS source.

Wow...  I wonder how many people who joined the NATS trial realised that the settings meant the transmission would not be used by anyone except Flight Radar 24... I'm out, and staying with a plain vanilla non ADSB transponder.

[Richard]

I'm In as the interest in flight safety. In flight I want to See You.,...

[AlanB]

I knew before and I'm still in.

The more ADS-B out there then I can see, and avoid, you.

I'm also of the opinion that as the data is gathered the stability of the non-certified GPS data can be proven and we can get the integrity level up and therefore seen by TCAS and other certified units.

Maybe one to follow up though FASVIG.

Alan

[The Westmorland Flyer]

Interesting comments from Ade Price. One can sense that NATS (or at least he) would prefer us to be able to use a more sensible SDA value. You can bet your house that those glider pilots in Europe won't be setting SDA=SIL=0 when they connect up their uncertified GPS.

Yes, the trial settings of SIL=SDA=0 severely limits the usefulness for in cockpit conflict awareness. That means that a safety case can be made to that effect. The CAA runs on safety cases! It seems to me that the next stage in the process is to open negotiations with CAA SARG to lift the SIL=SDA=0 restriction for safety reasons. I would like to think that this is already under way as a conclusion to the trial.

Meanwhile, it's a numbers game. The more airframes that have ADS-B out AND ADS-B in (via, for example, PAW) the better our conflict awareness will be.

[ianfallon]

One would hope the TCAS software can easily be changed to deal with SIL/SDA = 0 and switched to "see" these in one form or another at some point in the future.
Definitely still "in" and very happy to be ahead of the ADS-B game.

[Paul_Sengupta]

Wow...  I wonder how many people who joined the NATS trial realised that the settings meant the transmission would not be used by anyone except Flight Radar 24... I'm out, and staying with a plain vanilla non ADSB transponder.

It's not just FR24, it's us lot too! The biggest collision threat is between GA and GA, and this will mean you pop up on GA setups. It won't pop up on airliner setups, but they have a proper TCAS which interrogates your transponder anyway, so I'm not that bothered about appearing to airliners. I'd really want to appear on any GA traffic systems though, and at least on the PAW we will.

[SteveHutt]

Thanks Chris,
Appreciate you getting that info from Adrian.

Here is an article on the work by John Brady of the LAA and FASVIG on risk of Mid-Air Collision (MAC).
http://content.yudu.com/Library/A2qa2r/FlightSafetySpring20/resources/8.htm

From that work, and as has been said already here, by far the greatest risk of MAC is between like aircraft - powered GA-on-powered GA, Glider-on-Glider.
Also, highest risk is in the vicinity of an airfield circuit. Please read the article - only 3 pages - it is all in there.

What proportion of GA has certified collision avoidance systems that will not see SIL=0,SDA=0 ADS-B?
A very small proportion I would suggest. And a proportion that is unlikely to grow very much due to the expense.
I would argue that most GA collision avoidance systems are likely to be uncertified and so will 'see' SIL-0,SDA=0 uncert GPS ADS-B Out.

I am a supporter of PilotAware but I view ADS-B Out as a much more valuable thing to broadcast than P3i.

• Everyone with ADS-B In (including PilotAware) will see ADS-B broadcasts.
• Only PilotAware users will see P3i Broadcasts.
• ADS-B Out (i.e. transponder) antennas will be fixed externally installed therefore offer more reliable transmissions that P3i
• ADS-B Out transmissions are more powerful

As has been said, things are still developing. ADS-B is not going to go away but how it is going to be used may well adapt with time.
And the usage of ADS-B may well have an influence on other things, airspace being an obvious candidate.

Steve

[The Westmorland Flyer]

Your points are all well made Steve. Trundling around the Scottish Highlands as I do gives one a slightly different perspective regarding MAC risks. There is a significant amount of (mostly) helicopter traffic in the form of Helimeds, pipeline surveys, oil rig/wind farm traffic and so on. Couple that with the lack of any radar coverage over vast tracts of lower airspace and it creates a different risk profile. Most of these aircraft come under the GA banner but they are usually equipped with TCAS and their ability to see uncertified ADS-B out would definitely be a benefit.

I completely agree that the real prize is universal, usable ADS-B out & in. I think PAW's principal contribution will, in time, be its ability to provide a useful ADS-B in capability that works with the likes of SkyDemon et al.