Hi I am using SD 38172 in iPhone connected to a Pilot Aware device with bearingless targets displayed.

On a recent flight I was surprised to receive an alert on screen warning about traffic "behind". Firstly I was not sure how you could tell that the traffic was behind being bearingless and more worryingly when I played the track back using Flight Aware the aircraft was actually ahead.

Thanks

Giles
0

Bearingless targets are neither behind nor in front. We have seen a couple of instances where SkyDemon is showing a warning for a bearingless target, which should never happen if the data coming over the network is correct, but not enough to have worked out what is going on. Are you sure the alert was for the bearingless target? If it happens again do you think you could get a screenshot?

Tim
‌
There is a ‌thread about this on the Pilot Aware forum
‌
http://forum.pilotaware.com/index.php/topic,940.0.html‌‌‌

‌‌‌at the bottom Ian Melville says he can reproduce the issue. Maybe he can send you a screenshot. As I say in the thread I think the issue is an SD issue but obviously the issue could equally be the data coming from PAW. Would be great to try and understand the cause.

B‌y the way I am a huge fan of the amazing SkyDemon software. Thank you.‌
‌
G‌iles‌

Interesting. If someone who can reproduce the issue could somehow capture the data coming from PilotAware so that I could play it back, we could obviously debug it.

I've gone through the code and my only suspicion is that perhaps we are trying to perform a collision analysis on a bearingless target, which shouldn't be possible due to the way the protocol works. I've put a check in place though, for our next version, to make absolutely sure it doesn't happen. ‌‌

Hi Tim, just registered on here to stop cross forum posting etc.
A‌s Giles has said, I have been experiencing this for a month or more now. I have been using SD and PAW for over 12 moths now, so something changed that has caused or highlighted a hidden issue. When I first experienced the issue I was using a 1st generation iPad mini, which was running very slow. I would get an audio alarm of the traffic, and a message would pop up on the screen long enough to read it easily. I have since wiped that iPad Mini and it is running quicker. Now the alarm is still the same, but the message flashes on the screen so fast that it is not possible to read all of it, certainly too fast to take a screen shot. Most, if not all the traffic is mode S, so I am able to see a call sign and the fact the traffic is behind me. Sadly PAW playback does not playback bearing-less targets.

I‌ have come to a similar conclusion as you‌ mention in the above post. The alarm/alert is only received when in I in motion, and it does not have to be very fast. I suspect it is seeing the position of the alarm symbol (red ring) generated at my position, and my new position when it updates. That would make the bandit always in my six. Would that be down the order the code modules were processed?
‌
What I find surprising is that there are not more reports of this issue. Is it something that Giles and I have set, that others do not? or is it because we are all keeping our distance in flight?
‌
I‌ find it easier to produce when driving for some reason, as I don't normally let other aircraft get that close‌. Should this make any difference?
I‌ will have a go at videoing the screen over the next few days, but will be away on holiday for next week.

C‌heers
I‌an‌
SD V‌ersion 3.8.1.72‌

Thanks Ian. I do not know the answers to most of your questions. We've only had a few reports of it too, and since there are really no configurable options, it's a bit of a mystery. There might be something in the protocol where a target goes from bearingless to bearing-full (which ought to be impossible) which could potentially trigger such a thing, but as I said, I'm hopeful that my fix in 3.8.2 will have put it to rest.

Hi Tim. If I wish to test/beta 3.8.2 is that possible?

Giles

If you're on iOS you'd need an invite to our iOS beta programme. Just contact our support.

I've experienced this strange message as well. It comes and disappears that fast, I hardly can read it.

It says something like 'Traffic at 12 o'clock behind' or similar. I'm sure I've read "12 o'clock" and "behind" in the same message.

Eric