2 or 3 factors combining into a loss of separation.
Was it: - VFR in VMC - Uncontrolled IFR in Class G - Controlled IFR on Airways?
I was flying with a fellow pilot VFR to Mannheim EDFM last week on low altitude and it was scaring me:
It felt quite unsafe. There was probably a lot of traffic on their way to the Tannkosh flyin.
Flying IFR on Airways gives me a safe feeling with regard to separation...
VMC, VFR, Class G, entering an aerodrome circuit.
The best thing to do is avoid going anywhere near airfields, but one has to do it to depart and arrive.
The departure is fairly easy because a straight out departure, keeping below circuit height for say 3nm, ought to do it.
In the past two years, I learned a lot about how and where people depart and join around Biggin. I am using the following "strategies" to reduce the likelihood of conflict:
I am at circuit height (1,600 ft MSL) well before joining, 5 miles typically - most departing traffic is at least 400ft above (2,000 ft is very popular)
I always depart above circuit height, going for the highest departure height (2,400 ft) quickly. This avoids joining traffic descending leisurely from their cruise altitude.
from the East, I join between the main departure points - Sevenoaks and Swanley
Had I adopted these years ago, my two near-collisions (one not too bad, one brown trousers moment) would not have occurred. And they are good "socially" since they would continue to work if everyone did it that way, but don't rely on it.
I am also very careful never to cross the runway line from the dead side outside the runway dimensions - several mid-airs happened on crosswind, including the shoreham one, I believe.
The amount of traffic I know is there and I don't see is scary
Any other tips / strategies (other than fitting a traffic awareness system)?
How do you square up
I always depart above circuit height, going for the highest departure height (2,400 ft) quickly. This avoids joining traffic descending leisurely from their cruise altitude.
with
I am also very careful never to cross the runway line from the dead side outside the runway dimensions - several mid-airs happened on crosswind, including the shoreham one, I believe.
The problem is with some people climbing enthusiastically to around circuit height overhead the upwind numbers, which one can see is exhilarating especially if you paid the money for a type capable of it on a 1000m runway.
Any other tips / strategies (other than fitting a traffic awareness system)?
Make position reports (accurate ones, obviously) with height. And repeat the position report immediately upon getting transferred from e.g. approach to tower.
I think a relatively steep descent into the circuit is also a good idea, because it gives you a better view of the circuit in that planes are better visible against the ground than against the sky - especially all-white ones which most "plastic" planes are. And it gives you better options for aborting (climbing back up), in the same way that flying a steep descent to a landing gives you better options in case of a go-around (runway blockage, extreme wind shear, etc).
planes are better visible against the ground than against the sky
I find the opposite to be the case for me.
I have been known to approach certain airfields a few hundred feet below their circuit height. Black dots in the sky are very easy to see. Once I get near the airfield or circuit, I pop up to circuit height and join in the normal fashion. Works well for me.
Black dots in the sky - definitely.
But many are all white.
The RAF paints their trainers black, I believe. Certainly the Tucanos are black. They are much more visible against the sky, but not against the ground.
Peter - this is just playing devil's advocate and I'm sure the answer is no, but.....
Are there any possible holes in the TCAS technology which could cause a spurious contact to appear, i.e. an indication where there is in fact nothing....? Or where that contact is appearing in an erroneous position and is in fact elsewhere?
I am pretty sceptical about the effectiveness of keeping a lookout.
On a solo sortie during my PPL training, I was 'bumped' by a bizjet descending over the top of me, i.e. it came from above and behind me on the same track and descended through my level just in front of me. In class G and not in receipt of a radar service. At the time I didn't know what constituted 'close', although I now know that it wasn't scarily close but close enough to make you say "oh crikey..."
Upon mentioning to my instructor I was admonished for not keeping a better lookout. I took the tongue-lashing without complaint, but was left thinking " in a PA28, how the hell am I supposed to ever see something approaching me from above and behind?"
Though without TCAS or a radar service it is all we have, so one might as well try.
Perhaps I should not have used the word 'black'. I find that a background of sky provides great contrast for spotting virtually all aircraft, even white ones. They all appear as dark objects against a bright sky.
Are there any possible holes in the TCAS technology which could cause a spurious contact to appear, i.e. an indication where there is in fact nothing....?
I think this is incredibly unlikely if the contact has a plausible trajectory.
This isn't primary radar. This thing does transponder returns only. So you have to have a transponder out there.
It's Mode C return could be duff and that is by far the most likely error source - if there is an error.
Or where that contact is appearing in an erroneous position and is in fact elsewhere?
You can switch 9 o'clock for 3 o'clock just by switching over the cables on the antenna with the two side by side blades. Or 6 o'clock for 12 o'clock by switching the ones on the antenna with the single blade (which actually contains two blades, one in front of the other).
Don't ask how I know 
There can be other altitude errors e.g. the TAS box gets the pressure altitude from the altitude encoder (directly) and that could be wrong if e.g. a wire comes off. But that would not affect the distance and azimuth info.
In general one does see enough targets to fairly quickly realise something is not right - even if one sees only 10% of them.
There can be, I am sure, other failures modes in the TAS box itself but I can't see that you would get a plausible display sometimes and not other times, and since you will see some of the targets you would soon realise something isn't right.
Also you can see ground targets when you start up (showing +00 or so) and you can see people in the circuit when you are on the ground (showing +10 or so, and in plausible positions) so you get a good idea right from the start.
It's a good system - a pity about the price.
Upon mentioning to my instructor I was admonished for not keeping a better lookout. I took the tongue-lashing without complaint, but was left thinking " in a PA28, how the hell am I supposed to ever see something approaching me from above and behind?"
That's pretty standard...
