[Tim Dawson]

I would be very interested in a discussion on the human factors associated with the reception of so-called bearingless targets with EC.

Are they useful? Are they a distraction? Are they both?

[johnm]

I would be very interested in a discussion on the human factors associated with the reception of so-called bearingless targets with EC.

Are they useful? Are they a distraction? Are they both?

If I have no idea where it is the info is useless. If I’m told aircraft in my 10 o’clock 5 miles I know I won’t see it unless it converges, but I can focus my scan a bit.

[Paul_Sengupta]

Are they useful?

For those who receive them, yes, they are very valuable. From personal experience and from all the requests of the past, absolutely. In fact, a couple of whole units used to be on sale with their sole raison d'etre to be to gives bearingless targets.

http://www.digitalreviews.net/reviews/miscellaneous/zaon-mrx-portable-collision-avoidance-system-reviewed.html

http://www.avionicslist.com/articles/monroy-atd-200.php

Are they a distraction?

Yes of course, they will distract you from whatever you're doing and have a good look around for traffic.

[Dave W]

To me, this is where an unknown Human Factors element comes in.

Taking the SD/PAW example: When I get a green circle, I start to look around with extra vigour. The trouble is, I don't know where to look, and the aircraft might be behind me.

Let's assume I don't see it, and the circle goes yellow. I then start looking even harder. It is very easy to get into a situation where the ONLY thing I am doing is looking for that elusive traffic; it becomes distracting from other in-flight tasks. I have to work not to allow that to happen.

What seems to reduce the workload for bearingless traffic is to scan as usual, and only respond when there is a definite threat notified.

To put it another way, use the SD/TAS combination as a threat response system rather than - as is all too easy to do, bearingless or otherwise - as a form of ATS radar picture. I shouldn't care if there's something a mile away heading 90 from me, but it is easy to get drawn in if you let the system do that to you.

I think what I'm saying is that HF should drive consideration of where you (and the system designer) set the alerts, and there is more work to be done to understand where best those settings might most effectively be.

(Not sure I've explained myself very well above. Might have another go later.)

[Paul_Sengupta]

I think the mistake made by those who don't like bearingless information is to assume we're all spending every single second while flying scanning for traffic the best we can. I can't speak for anyone else, but I certainly don't do that. It's not really to do with complacency or having a traffic display or not, it's just human nature, we want to enjoy our flight, relax a bit, look at things on the ground, enjoy the flying in and of itself, then there are things like working the radio, and in-cockpit things like tuning the radio, setting the transponder, etc.

My reaction is similar to Dave's...green means having a quick scan around (and you should know the altitude difference so you know whether to look against the ground or against the sky), yellow means having a better look around and red means be very aware, scan around quickly.

Also the angle/elevation where you're scanning will change. If something is green and 200ft above, it'll probably be not far from the horizon. If it's red and 200ft above, it could be at much higher angles up to and including directly above.

Will traffic information cause me to pay more attention to looking for the traffic than taking photos of the aircraft carrier? Sure. Is that a down side of receiving traffic information? I don't think it is.

[PaulB]

Also the angle/elevation where you're scanning will change. If something is green and 200ft above, it'll probably be not far from the horizon. If it's red and 200ft above, it could be at much higher angles up to and including directly above.

Little details like this are really important and may not have been thought of by everyone.

EC is here to stay and we should be thinking now what best practice should be so that it can be taught in the future).

[mo0g]

To me, this is where an unknown Human Factors element comes in.

(Not sure I've explained myself very well above. Might have another go later.)

I think I understood it, I am not the same, I would barely heed a green circle, as its telling me something is around but of no consequence at the moment.

If it turned yellow I would then start a more concerted look out.

If it turned red I would be concentrating on areas where a converging aircraft could come from, it at or around my level, ahead and to the left and right.

Maybe what we need is fully customisable alerts - you could skip green or green and yellow if you wanted, or change the ranges involved to be closer so when you got them it warranted your level of 'distraction'?

[Paul_Sengupta]

change the ranges involved to be closer so when you got them it warranted your level of 'distraction'?

You do this on a PilotAware, not just to suit a person's personal preference, but to adapt for different receiving antennas and positions, as range is done on signal strength.

[GrahamB]

But signal strength in itself is not really meaningful.

A green circle could be an airliner descending through your level 15 miles away, or a GA type with a barely serviceable transponder and an oil-grimed antenna about to ram you from underneath.

[Dave W]

But signal strength in itself is not really meaningful.

Well, yes.

But it's the only thing anyone has got if you want any indication of the presence of Mode C only or Mode S only aircraft. So your choices are to put up with that limitation, or switch that bearingless function off.

A green circle could be an airliner descending through your level 15 miles away, or a GA type with a barely serviceable transponder and an oil-grimed antenna about to ram you from underneath.

(My bold) Not quite that; you'll get relative altitude info displayed via the Mode C element of the threat aircraft's transmission.

[GrahamB]

But it's the only thing anyone has got if you want any indication of the presence of Mode C only or Mode S only aircraft. So your choices are to put up with that limitation, or switch that bearingless function off.

As a PAW user now for over two years, I'm still struggling with whether I find bearingless warnings of value or not, particularly for Mode C where there is still noise from one's own transponder.

[Flyin'Dutch']

Instead of looking it may be useful to climb or descend to maximise the height difference.

[Pete L]

the aircraft might be behind me.

And it is getting round to that time of year.

I'll get my dame outfit.

[Dave W]

Oh no, you won't.

[Tim Dawson]

I find it concerning that people would behave differently based on the green, yellow or red colouring of the "bearingless" circle. The reason I find it concerning is that the distinction between when you get those colours isn't well documented (happy to be corrected) and is at best an arbitrary guess by the receiver as to how far away the other aircraft is.

As someone else pointed out, a green circle could just be a low powered or damaged transponder, on an aircraft about to collide with you. And a red circle which is going to make you sit up and take notice (distract you) could be an airliner taking off 15 miles away.

The fact the distance is guesswork but that people are responding differently based on the colours produced by the guesswork is what I find worrying about the whole user experience of bearingless targets.