My concern when OCTA is IFR from VFR separation. That is where TCAS systems help although only from transponder traffic.
Non participating traffic in Class E is supposed to be in VMC, but that doesn’t mean you will see it. Some 90% of traffic is never seen.
If that statement were true, then VFR would be impossible. See and avoid does work for both VFR and IFR in VMC. In Germany you just go at FL100, that is a known traffic environment. Even when VFR, you get that advantage.
The ATC service level in the UK is rather poor but in return you get almost unlimited freedom with IFR in G, DIY approaches, farmstrip landings, non transponder / radio etc. You can’t have all it seems…
I think that is an illusion, unless you mandate Mode C/S transponders for all
you are correct, Peter. In Germany there is no separation in class “E” airspace (up to FL100) between IFR and VFR traffic. Therefore when flying IFR below FL100 you have to look out carefully. Transponders are only mandatory above 5000ft MSL or above 3000ft GND in high terrain. So flying IFR above 5000ft you can expect traffic advisory in case of unknown VFR traffic.
Up to the mid-seventies the German airspace above FL245 was only Upper Advisory Area – i.e. they only separated known civil IFR traffic. The military had their own TACAN airways which crossed civil airways at many places e.g. “NOR” Norvenich, they had their own control centers and there was hardly any coordination. It was still the “Cold War” and all western airforces drilled holes in the air mostly VFR. Too many near-misses and incidents led to an upper controlled airspace and to a speed restriction of 250kt below FL100.
It must be an illusion since you can have non-radio and non-transponder traffic in Class E.
You have IFR to IFR separation. So this is not your concern. As Jason stated, the concern is the VFR traffic. But there are higher visibility minimums in E and mode S required > 5000 ft.
If that statement were true, then VFR would be impossible.
I would not say that. VFR works because the sky is big. The probability of a mid-air between two planes with say a 10m wingspan is extremely low.
Obviously lookout does work for separation for the traffic you do see (in that you won’t hit somebody knowingly, and actually the same goes for terrain, with the exception of unusual cases like people flying towards the end of a box canyon) but if you spend a bit of time flying with TCAS you realise that most traffic is not spotted even if you know roughly where to look for it. Everybody I have in the cockpit finds the same.
Much of the flight regulation we have today is based on beliefs and emotions which go back decades and which cannot be challenged not because they are correct but because there is nothing better (practically – you cannot mandate Mode C/S and TCAS… though one day in the distant future we probably will have mandatory ADS-B in and out 
)
The ATC service level in the UK is rather poor but in return you get almost unlimited freedom with IFR in G, DIY approaches, farmstrip landings, non transponder / radio etc. You can’t have all it seems…
The ATC service is poor but frankly – except stuff like picking up an IFR clearance while flying – it doesn’t make any difference. The advantages of the other stuff are tremendous.
But there are higher visibility minimums in E and mode S required > 5000 ft.
None of that means anything. Spotting far away traffic (5000m or 10000m away) is very hard; almost impossible if on a genuine collision trajectory (i.e. a stationary point in the sky).
Although I do think increasing use of very accurate GPS means that the big sky theory starts to unwind a bit. Two planes can both end up exactly at x turning point. And in the UK so much traffic is pushed down low that random vertical separation is much less than you would think.
There are some well known bottle necks under the LTMA eg LAM, CPT which are worth avoiding overflying with pedantic precision, including in IMC
I agree about the navaid-proximity bottlenecks but from TCAS indications I see them being a far smaller problem than flying in the vicinity of aerodromes.
Aerodromes are easy to avoid of course if you are enroute, but sometimes you have to depart from it or land there, and then you have a really big problem. The “big sky” comes to your rescue – except for approx 2 aircraft per year, in the UK…
My view is that one needs to fly defensively which means depart straight out and get out of there ASAP and not come back anywhere near the circuit. A particularly hazardous time is crosswind-join traffic conflicting with departing traffic (the last Shoreham mid-air). And on landing, if there is conflict then just go around and get out of there and not come back into the circuit unless the circuit is clean. Occasionally I go around on a TCAS return which I can’t see – why bet against known odds?
The same problem must exist in any GA-busy country i.e. UK, Germany, France, and popular airfields in a few other places.
Two planes can both end up exactly at x turning point.
That must be true in terms of eroding separation but the midair data doesn’t support it as an accident risk, and GA activity is heading downwards. I don’t think there have been any midairs between “unrelated” aircraft flying enroute. Also most were very low down. The RAF 2xGrob was high (4000ft+ I think) but they were in a loose formation and lost visual contact. The RAF immediately spent some huge amount equipping their Grob fleet with TCAS. It must have been well upwards of £20k per aircraft, possibly 2x that, knowing who did the work and since each had a Sandel SN3500 installed to display the data and presumably they must have needed a heading source for that…
But back to the original question, you can either descend under IFR and than cancel IFR when you are visual, or make an approach somewhere else and proceed to North Weald in VMC at a legal low level.
North Weald is interesting as Kelvedon mast is within 5nm requiring 1700 agl as MSA for let down purposes, but you need to be below 1,500’ to avoid Stansted Class D in the vicinity.
You also have quite a lot of IMC traffic OCAS in the vicinity at Stapleford and LAM.
