I only partly sympathise with that statement. I'd probably say in VMC I would see just over half of the traffic advised to me either by ATC (if I am getting a traffic service, and looking out extremely hard) or it is picked up by the Zaon XRX. In some of those cases (maybe another half very loosely speaking) I would see the traffic before being warned (so maybe it a few miles away and posing no danger).
Therefore the MK1 eyeball is not totally useless, but it is 'enhanced' by ATC and or technical products like TCAS and so on. I am flying mostly OCAS, and would I have the confidence (even if I had full TCAS) to not look out of the plane's window for more than a few minutes at a time - no.
One has to look out, due to the % of nontransponding targets.
But the % of Mode A only, or no-TX targets, falls rapidly above ~ 2000ft.
TCAS is just a partial "heads up" solution. But it's a lot better than nothing.
That's my experience as well, Peter. Last week I was flying over the North Sea in the Schiphol TMA and I heard a lot of airliner traffic in my vicinity. The PCAS showed traffic constantly in the range of 2-5NM. How hard I tried, I never spotted a single one.
We spot movement, so we only really spot targets with relative movement, i.e. targets we are not goiing to hit anyway. With no relative movement its hard to spot another aircraft, even against the sky. Against ground clutter its almost impossible.
We spot movement, so we only really spot targets with relative movement
Which is why lookout is dependent on technique, to create relative movement and to refocus the eye. I recall the best lookout pilot I have ever known only had one eye, he probably had to move it more than with a fully functioning pair.
That is why I prefer to fly in CAS.
The "Mk 1 Eyeball" is PROB99 an old Royal Air Force expression, for keeping a lookout.
I completely agree. There are several articles and research papers published on the severe limitations on unalerted see-and-avoid.
The bottom line is to:
1) Make use of ATC services where available and
2) Install PCAS or similar equipment
to help you to conduct a directed traffic search.
The bottom line is to:
... 3) Fly at a high level.
Most traffic seem to be at low VFR altitudes (like 1500ft AGL). I think that is because people are teached to fly at such altitude during the X-country training...
I remember once, whilst receiving a traffic service from an RAF LARS unit, I was alerted to opposite direction head-on traffic at my 12-o'clock, same level (2,000 ft). The other aircraft was also talking to the LARS unit and he was alerted to my position.
We each adjusted our altitude a little, major changes not being possible due to mil traffic and cloud base. The controller gave frequent position updates and promised to advise if avoiding action was necessary.
We passed within 0.5nm of each other and within a few hundred feet vertically. My eyes were outside the cockpit scanning for that aircraft the whole time. Neither of us saw the other. I realised at that point that just looking out was next to useless.
Now I fly as high as possible, take a service from the nearest radar unit and rarely hear of any other traffic up there with me.
What suprises me is that a lot, say very roughly 30%, of traffic I see on TCAS and which I would consider definitely of interest, is not reported to me by a radar service.
What I can't tell is whether they are not doing it due to controller workload (there is no obligation for them to report all, or indeed any, contacts) or whether they can't see it.
But if I see it it must be SSR visible. Are ATC radars configured to not show SSR-only targets? That would be stupid, IMHO, because the SSR should be visible long before the primary return, and obviously the SSR return cannot be spurious; there has to be "something there" with a transponder screwed onto it.
I am pretty sure that, in the UK, ATC is not allowed to provide official separation against an SSR-only target, so maybe that is what is happening.
The other side of it is that they do report a lot of stuff which I don't see, even telling me their altitude, but that could be on non-TXP targets who are in radio contact and have reported their altitude.
On longer trips, Eurocontrol IFR, one sees almost nothing. Just the odd airliner which happens to be within my configured +/- 2900ft band and within 10nm... maybe 2 or 3 on an 800nm flight. Then you get back to Shoreham and the place lights up like a xmas tree.
