Primarily for general aviation discussion, but other aviation topics are also welcome.
#1856637
thegasguy wrote:Leemore1966:
I agree on lead 'reality' position - I could not have caught it.
The position beside, and more or less parallel track to me - on screen - is indisputable.
Seen by two of us, and a wide awake jolt to me as it was converging a little.
I was properly concentrating then, as it looked as if we would converge in a few minutes. No mistake about that.

I took a picture on my phone of the screen at one point, I'll have a look to see if it is of anything useful.

I have it, just north of Plumpton racecourse, I'm apparently just behind and 400' above.
I'll try to put it up now.
Image


What do you have the index marks on your predicted flight path set at ?

If they are set to where you will be in the default (?) 2 and 5 minutes ahead , that
might indicate that you are some miles behind the other aircraft at the time of the screenshot. ( and a quick look at that area on SD would seem to show a separation of around 3 miles).
By thegasguy
#1856678
The marks are set to the default, as you say.
I've had a quick look at the bigger picture and think it shows about 2 to 2 1/2 mile separation.
I should have been able to spot him I think, but agree that it's reasonable that I could not.

It's a shame I didn't get a pic earlier, I was a lot closer and more or less beside him.
I got a lot of practise spotting aircraft shown on screen and could always see them.
Not this time.

Maybe it was me - I don't think so, but we will never know now.
#1857206
@thegasguy

Having had a recent eye test, I know for certain that my distance vision is still near perfect.

As a member of the PilotAware Development Team since 2015 and a ZAON PCAS User for several years before that, I have bucketloads of experience in tracking and trying to spot aircraft in flight from ‘known locations’ on EC displays. I also took part in the Project EVA trials, out of which the current EC rules were developed and which through investigating delay between aircraft becoming visible ‘on-screen’ and being acquired visually with the naked eye definitively put to bed the ridiculous claims of the ‘rely on the Mk.1 eyeball brigade’.

Experience from Project Eva supplemented by our own testing (and practical in-flight use) of a variety of EC equipment and displays indicates that positional reliability from the sort of equipment we are talking about (including DF17 Mode S/ES ADSB from transponders Using uncertified GPS position sources) runs at in the region of 99% reliability for directly received transmissions (which is all your SE2 can report) except where there are problems with the GPS signal - when most units simply stop transmitting their position.

I was about to post re the relative distance when @Charliesixtysix posted above. I fully concur with his comments. Whether your SD Aircraft Trajectory Display is set at ‘Minutes’ or ‘Miles’ the result is effectively the same - G-AYGG was at least 3+ miles ahead, 400 ft below, and relatively close to your own heading, which would have made it extremely difficult to spot visually.

That still doesn’t of course explain your ‘on-screen’ results, but all the evidence so far indicates that the aircraft were where they were reporting to be and that the ‘problem’ was at your end (though most likely simply an issue of visual range).
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#1861046
exfirepro wrote:Having had a recent eye test, I know for certain that my distance vision is still near perfect.

Me too. And with this thread very much in mind I took very careful note whilst flying with Nick of this very forum over a few days.

It started on leaving Glenforsa for Tiree and Coll, I departed first, Nick let an arrival land and then followed. I was somewhat in disbelief that Nick couldn't see me despite catching me and knowing where I was. Coll and Tiree being under an undercast we turned north putting me behind Nick. My aeroplane spotting was no better. After an hour and a half flying 'together' I only became visual with Nick when I was overhead and Nick was turning crosswind. :shock:

We very carefully verified that the EC position was accurately reporting where the aircraft were/was. For example; Nick, your aircraft is showing as 100' below me at xxxx' overhead the Ardnamurchan Lighthouse. This was verified. Yet I could not see him. We repeated similar over a few days, trying it whilst over the sea, over land, over cloud and had the same outcome. Now, I am not suggesting that an aircraft cannot be seen at distance. In fact I watched an aircraft return to Glenforsa which EC showed as opposite direction to Nick and passing directly underneath him. But I could not see Nick. The following day whilst visual with Nick I saw a twin pass directly under Nick 2200' feet below, which he saw on EC, but did not get visual. Neither of us were visual with the flexwing to the SE of the image, which was about 700' below. Nick had it on EC, I did not.

Image

It was certainly not scientific, however it was real life and the 'experiment' served to demonstrate, to me at least, just how fallible the MK1 is. There's no doubt it is an excellent piece of kit, yet fallible it is and consequently cannot be relied upon to see aircraft of interest within a couple of miles.

IMO the distances in themselves are not critical. The overall difficulty in spotting aircraft is the main factor. My conclusion is that the MK1 eyeball is being credited with the much more powerful influence of the big blue sky factor, resulting in many/most having a false sense of security in their ability to see other aircraft. It's the big sky that's keeping us safe and not the MK1. :wink:

With a blue fuse and bright yellow wings, It's not as if one could argue Nick's aeroplane is camouflaged. :wink:

Image
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By gaznav
#1861118
If you want to see how poor ‘see and avoid’ really is then Appendix C of the following link précis the main points nicely: https://assets.publishing.service.gov.u ... Append.pdf

These points were drafted by Mr John Chappelow, the Principle Psychologist on Human Performance for QinetiQ and previously DRA/DERA. I had the pleasure of listening to John’s lecture on the subject a couple of times - I came away amazed that I saw anything at all when I go flying. Passing the Snellen Chart eye test at a Class 1 or Class 2 is no guarantee to success either!
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By Nick
FLYER Club Member  FLYER Club Member
#1861161
I can only agree and underline everything Misc has said in his report above. His aircraft being bright yellow it stands out very well against the background, so definitely no issues of camouflage.

Once spotted, I thought how, on earth did I miss that!

Nick
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By MartinC
#1861222
I am fully on board with EC (any EC) as a concept and things can only improve in terms of take up and compatibility. The CAA rebates must have placed many more systems in GA aircraft over the past year which is fantastic in my book. However, a recent flight brought home the fact that electronics are only 70% of the picture (my invented stat) ,you still need to look out for non-radio /non-EC targets which won't appear on any device.

Recent flight, working Exeter frequency running along the coast towards Bournemouth, just about to hand off to Yeovil Radar, when Exeter advised another aircraft they weren't working just in front of us. Just as they said it, I spotted the aircraft, a PA28 about 400 yards off our starboard quarter, overtaking 500 below I would guess.

Plenty of other contacts on our EC (some even visible), but nothing shown on our EC device for the PA28, no transponder transmission, no radio chatter as they were not talking to Exeter either..... some aircraft are emitting nothing at all.
#1861258
There are quite a large number of aircraft just emitting Transponder Mode C which your chosen EC may not be picking up.
The majority of flying school aircraft for instance will only have a Mode C transponder .....and then it may may not be even turned on!
#1861266
Cub wrote:Misc. A useful and informative post and confirms everything I always thought having passed traffic information at short range to GA aircraft as a controller for 40 years.

Thanks Cub, just reporting what we found. :D There is of course are detail, however for simplicity of expressing my conclusion the detail doesn't greatly matter.

MartinC wrote:However, a recent flight brought home the fact that electronics are only 70% of the picture (my invented stat) ,you still need to look out for non-radio /non-EC targets which won't appear on any device.

This, as I have probably said before, is my biggest worry, The partitioning of detection methods. I don't see it, nor believe it is/should be this way. We cannot rely on the MK1 seeing the aircraft that are not EC equipped, nor can we rely on it seeing equipped aircraft which has not been detected. Likewise, we cannot rely on EC to detect all EC equipped aircraft. To my mind the MK1 and EC do not have distinct and separate jobs. They should be working together to complement each other, with an understanding that even then their combined effectiveness falls some way short of 100%.

No offence intended, Martin, however my fear is your approach of EC detects 70% leaving the MK1 with 30% to detect creates a false and worrying sense of security.

Apologies if I am misinterpreting your post.