@achimha wrote:
It’s one of those mantras you keep repeating and just for the record I keep answering with my mantra: I strongly disagree. I see virtually all traffic that either my PowerFLARM or ATC hint to and all traffic I see — with very few exceptions — is shown on my PowerFLARM.
It’s a bit off-topic, but my club is considering installing PowerFLARM. What display do you use? Any recommendations?
How do you maintain separation if in IMC?
1) By making use of FIS
What % of OCAS aircraft talk to FIS? 1%? 10%? And if FIS doesn’t have radar and is allowed to use it, including down to the altitude you are at, it’s worthless.
CAS is no guarantee that you maintain separation or even avoid collisions.
True, but like all the other factors it improves the odds by a huge factor.
Especially here in the UK where any fresh PPL is sh*t scared of entering that utterly prohibited piece of the sky called “airways” 
I recall reading one report where it was thought that the pilot pulled the wings off the plane to avoid busting the Gatwick CAS…
That said, I was once offered a mutual photo session, in CAS, with transponders off. The pilot who suggested it does live south of the Alps, but only just south… I didn’t take him up on his kind offer. Maybe it works for him because his plane is a fibreglass homebuilt. OTOH I did hear him getting a bollocking from Pula Radar (CAS bust) so he is not invisible.
I see virtually all traffic that either my PowerFLARM or ATC hint to and all traffic I see — with very few exceptions — is shown on my PowerFLARM.
I guess Germany is highly compliant. Here in the UK perhaps 1/2 the traffic below 2000ft is Mode A or non-TXP, and virtually no powered traffic radiates FLARM. And there is no product on the market currently which displays FLARM targets and gives you azimuth info on Mode C targets.
That’s why it is not a good idea to ignore the distance to cloud minima for VMC.
That’s hard to achieve if you are climbing up through cloud… fortunately almost nobody flies in or above cloud. Gliders do fly in cloud or just below it, but normally not above because there is no lift.
If say the CAS base is 2500ft, the cloudbase is 2300ft, it is far safer to fly at 2200ft than at 2000ft, because so many people fly at 2000ft. And loads of people fly at 1500ft. But the safest place would be 2400ft.
Peter wrote:
What % of OCAS aircraft talk to FIS? 1%? 10%? And if FIS doesn’t have radar and is allowed to use it, including down to the altitude you are at, it’s worthless.
The interesting question is how many OCAS aircraft in IMC are talking to FIS. I would say that in a country with a decent FIS, the proportion will be very high. Even higher if radio contact with FIS is compulsory for IFR traffic, as it is in Sweden above 5000 ft and down to ground level around most uncontrolled IFR airports.
Even without radar, a procedural traffic information service is far from worthless in areas with little traffic, and that’s what we are talking about here. (More or less by definition, for if the amount of IFR traffic was large, then the airspace would be controlled.)
Peter wrote:
And if FIS doesn’t have radar and is allowed to use it
You’re extrapolating your UK experience. In Switzerland, they nowadays can (and do) use Radar for traffic information (mostly thanks to the work of Melanie Streit). In Germany, they always used Radar to give traffic information, for as long as I can remember. In France, and South East Europe (such as Slovenia, Croatia, Serbia, Hungary…) it often is the same controller that handles IFR and VFR, and thus is a full ATCO with Radar.
Airborne_Again wrote:
It’s a bit off-topic, but my club is considering installing PowerFLARM. What display do you use? Any recommendations?
PowerFLARM got its own display and outputs TIS which I display on my yoke mounted Garmin 695. I believe there are other units from Garrecht/Butterfly which even radiate the traffic data via wifi which can be displayed on SkyDemon.
Airborne_Again wrote:
You should note that in Sweden scheduled commercial air traffic regularly fly uncontrolled IFR in IMC. You don’t hear a lot about CAT colliding in Sweden, do you?
I would claim that own-separation using TCAS is superior to ATC separation and outside terminal areas, ATC adds very little value in terms of safety, it’s mostly convenience. After Überlingen, TCAS now officially trumps ATC. If we gave up ATC separation, we could vastly increase capacity with the same or better safety. Also save a lot of money…
I was not talking so much about IFR aircraft coming out of the clouds, but about other VFR aircraft (including gliders) doing the same as you. That risk I would say is bigger than colliding with another aircraft in full IMC by a factor of 1000…
Hmmm … on the days I have to scud run home a couple of miles there’s really very few gliders in the air and (b) … WHY it is should be more risky to look out for traffic at 500 ft AGL than to fly in IMC without having the chance to see anything is beyond my imagination. But, as I said, i am only a bloody amateur.
Let alone that one days like that there’s almost no VFR aircraft in the air.
After Überlingen, TCAS now officially trumps ATC
Surely, TCAS always trumps ATC.
And GPWS always trumps TCAS
Weather trumps ATC too 
WHY it is should be more risky to look out for traffic at 500 ft AGL but to fly in IMC without having the chance to see anything is beyond my imagination
I would say there are more aircraft flying at 499ft than there are ever flying in IMC. There is a significant sub-community in GA who “always fly”. (well until they hit something) Plus, helicopters happily fly at 300-500ft.
But both figures will be low because most VFR pilots will not go out in OVC005.
I accept that emotionally this “russian roulette” is hard to accept. But the stats support it by a huge margin.
I also think that of the people who fairly routinely fly in IMC (let’s say not 500ft but something “normal”) are mostly competent pilots with reasonable hardware (whether they are doing it legally is a separate debate) and nearly all will be Mode C, so with a copious application of money you can buy yourself a warning system which actually works pretty well. It gives you the bearing, the distance and the altitude. Currently, outside specific communities (gliding, in some countries) and maybe specific countries (maybe parts of Germany?) almost nobody radiates FLARM and practically nobody radiates ADS-B, which makes an active-TCAS system stand far and away above anything else. For me it was money very well spent.
achimha wrote:
PowerFLARM got its own display and outputs TIS which I display on my yoke mounted Garmin 695
According to the FLARM website, PowerFLARM portable has its own display, but we would be using PowerFLARM Core for permanent installation with a panel display.
Is the TIS output good? I’ve heard claims that there are limitations compared to a dedicated FLARM display.
But the stats support it by a huge margin.
I would say the database is way too small to support either of the two scenarios. But to me (only me) scud running feels safer than illegal IMC, and as I said, my base is next to a very big airport and under a huge class C airspace. I would never climb into CAS/IMC from there without a clearance, but i don’t care if others do
No one is implying that you should enter controlled airspace without having a clearance, regardless if you are flying IFR or VFR in IMC or in VMC. Weren’t we discussing IFR in IMC in uncontrolled airspace?
