Pilotaware ATOM "This was the game changer on the day"

[Vic]

UK Airprox Board report on an incident at Turweston in December last year.

https://www.airproxboard.org.uk/uploadedFiles/Content/Standard_content/Airprox_report_files/2020/Airprox%20Report%202020167.pdf

Turweston are lucky to be involved with the team at PilotAware and have worked with them to help
develop the Air Traffic Overview & Management (ATOM) system. This was the game changer on the
day as the AGO was able to observe the track of the military aircraft and it was obvious to them that it
would fly through or close to the airfield circuit. So they took the decision on safety grounds to make a
general broadcast to all traffic making them aware of the jet and its position/altitude and the fact that its
track may have put it into conflict, or at least surprise, the Turweston circuit traffic.

Obviously this will spark the debate (I'm thinking Flyer forum here ) of whether the AGO should have done what he did in effectively pass traffic info but hey, he'll have had to live with the consequences  if he hadn't and things had worked out differently!

The UKAB have made it pretty clear to me though, that, in the circumstances, he did the right thing..

The Board first looked at the actions of the AGO. In providing an AGS, they were not required to provide
Traffic Information, other than to pass on known position reports from other pilots. Nevertheless, the
PilotAware ATOM provided the AGO with information that the Phenom was approaching from the north,
and the AGO broadcast this information to the circuit traffic. The Board commended the AGO for their
actions; although some advisors to the Board cautioned against the reliance on, and usage of,
unlicenced equipment and the lack of training thereof. Certainly, a CAA advisor was concerned that an
enthusiastic, but unqualified, AGO could potentially pass inaccurate information that then distracted a
pilot and that the lines between a controller using a calibrated radar and an enthusiast using a web
based program could become blurred; leading to potential confusion for pilots as to the type of service
 being provided. This view was echoed by an MAA advisor who noted that such web-based programmes
could potentially have a lag of up to 7 minutes, meaning that it was not possible to know how accurate
the information was at any given time. Nevertheless, on this occasion, the actions of the AGO had cued
the RV9 pilot to look for, and see, the Phenom and the majority of members thought that it was a positive
result

I see the RV had a Skyecho, but seemingly didn't 'see' the Phenom with that!

[Vince]

I see the RV had a Skyecho, but seemingly didn't 'see' the Phenom with that!

Was the Phenom outputting ADS-B or Flarm as it it wasn’t then SE2 would not see it and this shouldn’t be a surprise.

I see the RC had a Skyecho, but seemingly the Phenom didn’t ‘see’ it but then does the Phenom have ADS-B in?

[steveu]

I see the RV had a Skyecho, but seemingly didn't 'see' the Phenom with that!

Was the Phenom outputting ADS-B or Flarm as it it wasn’t then SE2 would not see it and this shouldn’t be a surprise.

I see the RC had a Skyecho, but seemingly the Phenom didn’t ‘see’ it but then does the Phenom have ADS-B in?

In the Recorded Section above Reported it is alleged that the Phenom was putting out Modes A, C & S. The RV9 was Mode A/C. Now, Sky Echo 2 had bearingless turned off in software a few revisions back, so it wouldn't have seen the Phenom. The Phenom was running TCAS II, so depending on the current SIL/SDA value output the by the SE2, the Phenom might have seen it, but without knowing what they trigger on, and if they ignore CAP1391, I can't say.

However, TCAS II should be able to interrogate a transponder?

My own very brief experience with the SE2 on the dash is that the range isn't great and is not uniform 360 degrees round. However, it should be good enough for close up stuff.

ATOM would have seen the Phenom via 3D mode-S, or MLAT, or whatever you want to call it.

As for the Flyer forums... shrugs... awaits homogeneous echo from the chamber tainted with self righteous indignation...

Now a PAW in the aircraft would have started audio warnings with "Traffic, six o'clock, level, 3km" and got keener as time passed.

The audio is so under rated for dealing with aircraft with a location...

[SGS66]

I have a couple of mates with their own aircraft and have SE2s and I have been checking on how a local ATOM station 'sees' these aircraft using James' new facility /GROUNDSTATIONS at AIRCREW. it does not seem that ATOM stations get them very well and it therefore makes me think I am unlikely to get good reception of them with my PAW Rosetta. Actually I have flown in convoy with one mate and never picked anything up, he only has Mode C and SE2. I even wonder whether it might make sense for ATOM stations to re-broadcast anything from SE2 so that we have more of a chance to 'see' something.

[steveu]

I have a couple of mates with their own aircraft and have SE2s and I have been checking on how a local ATOM station 'sees' these aircraft using James' new facility /GROUNDSTATIONS at AIRCREW. it does not seem that ATOM stations get them very well and it therefore makes me think I am unlikely to get good reception of them with my PAW Rosetta. Actually I have flown in convoy with one mate and never picked anything up, he only has Mode C and SE2. I even wonder whether it might make sense for ATOM stations to re-broadcast anything from SE2 so that we have more of a chance to 'see' something.

If the ATOMs don't see them or dont get them well then there's little or nothing to rebroadcast - as the SE2 is 1090MHz it should work well directly to your PAW.

I've done some flights with an SE2 and it was significantly below a PAW with external aerials on the same flight, in the same aircraft, performance wise. I prefer to check with Vector (pilotaware.com/analysis/vector) as it gives a simpler to understand 360 pattern if radiation. However, no point getting into arguments, different strokes for different folks...

[SGS66]

Steveu
I must have not made myself clear. I think ATOM stations are likely to be picking up more than more than my Rosetta when it comes the SE2 transmissions and that some supplemental info from ATOM stations would be useful.

[steveu]

Steveu
I must have not made myself clear. I think ATOM stations are likely to be picking up more than more than my Rosetta when it comes the SE2 transmissions and that some supplemental info from ATOM stations would be useful.

Have you considered that the problem might actually be the range of the SE2, and nothing to do with the ATOMs or PAW?

Why don't you put the ICAO code of the SE2s in question into Vector and see how well they perform?

Vector showed me that there was an obscuration problem with a SE2 I borrowed. I relocated it and the range and the all round conspicuity improved. However, it was still a long way behind a Rosetta with external aerials.

Maybe we should check the more basic things before we ask for the system to be re-jigged?

[SGS66]

SteveU,
Supposing the Guys with SE2 don't bother about your feelings - is there something ATOM stations can do to make this better for us.

[steveu]

SteveU,
Supposing the Guys with SE2 don't bother about your feelings - is there something ATOM stations can do to make this better for us.

I think the answer is no as I have done some measurements - maybe you can do your own measurements to compare the two devices and provide an alternative view?

[Admin]

SteveU,
Supposing the Guys with SE2 don't bother about your feelings - is there something ATOM stations can do to make this better for us.

We have thought about this ...
Even with the high gain antenna we use on ATOM, we are struggling to see SE2 in many installations
it seems there is a wide range of performance
But if we have no data, there is nothing to uplink 

Thx
Lee

[exfirepro]

SteveU,
Supposing the Guys with SE2 don't bother about your feelings - is there something ATOM stations can do to make this better for us.

When we first started out with PilotAware, we were guilty of not worrying too much about the gain and placement of antennas for the ‘1090 side’, as this side was dealing with (relatively) strong signals from high-power transponders. With the advent of CAP1391 however, evidence indicates that we all now need to revise our thinking in this respect and need to consider optimising our antennas and antenna placement to take account of the (comparatively) weaker signals from CAP1391 devices in the same way we always have for FLARM and P3i.

Regards
Peter

[steveu]

Comparison of ADS-B (grown up) and CAP1391. Aircraft results are similar. 20W v minimum 70W.

Any other evidence?

[Vince]

One thing to consider when comparing DF17 & DF18 reception is height of the aircraft. You will pick up many more DF17 signals from greater distance as many will be much higher than the DF18 signals. It would be interesting if you could place an upper limit on the graph to have a more alike comparison.

[steveu]

One thing to consider when comparing DF17 & DF18 reception is height of the aircraft. You will pick up many more DF17 signals from greater distance as many will be much higher than the DF18 signals. It would be interesting if you could place an upper limit on the graph to have a more alike comparison.

Vector graphs are similar when comparing PAW and SE2 from the aircraft. And the power output of PAW is a fraction of CAP1391. The height profile can be seen when logged into the ground station, and of course most CAP1391 aircraft are lower, and there are fewer of them but my own experience of the SE2 is as per the evidence I've submitted. I don't think it's for me to spend time on someone else's argument, if they are inclined, fine, if not.... IIRC the ADS-B reception is actually artificially limited at 80km...

ADS-B is 70W, and with external aerials... that's most of the difference I think I see here.

[SGS66]

Peter,

Thanks for your comment. But here is my problem. I own a PA28-181 and you cannot put outside aerials on this hull without a lot of trouble/expense permission wise. I have spent what some of the guys on this forum would class a lot of money in making my Garmin transponder 'ADSB out' certified. I say all this so you have the context.

What I am trying to say is that as with FLARM the ATOM stations might possibly transmit to us standard Rosetta types (inside aerials) some info on SE2 equipped aircraft... if that info is available to the ATOM stn.
 
We cannot expect the SE2 guys to optimise their transmissions, we can only be grateful they have done something and purchased some EC.

Can PAW ATOM stns redeem the situation a little without me having to drill holes in my PA28 ?