No, by embedded I mean a cloud filled sky in which the CBs are hidden.
You might for instance have a cloud layer that goes from 2000ft to 15000ft aan hidden in that are CBs. You can’t see them until you clear the cloud and instruments only pick up actual electrical activity which can suddenly occur but can then extend right through and across the cloud layer.
Positives trying to find the negatives or is it the other way round, I forget.
gallois wrote:
No, by embedded I mean a cloud filled sky in which the CBs are hidden.
I flew on Friday and Saturday in the conditions as depicted before, forecast told embedded CB for Friday and isolated CB for Saturday. Both turned out to be true. On Friday weather was a stationary front-like weather system. I could see the CBs on the Golze ADL because of the precipitation and I stayed away from that (but still in solid IMC with light rain). The best decision was that to start very early, so that even if I would get close to a CB it would not have the same energy as a full-grown afternoon CB. On Saturday I could see the CBs by looking outside and requesting left or right to avoid. The cross-section was alike that what I posted in this thread reply #33. It was few to broken sky, but still plenty of holes to drill through without having to enter much cloud.
An isolated CB has updraft in it and typically soaks in from a whole region. So around a CB, that is nothing different than a very big and mighty convective cloud, you will have a no-cloud ring with maybe few, but not overcast. So in case of isolated CB one should always be able to circumnavigate. I’d say in case of isolated CB and a forecast like few to broken flights can be safely performed when staying outside the convective clouds.
In case of embedded CB things might get difficult. If anyone has a good strategy please feel free to share 
My strategy with embedded CBs is to not fly.
Remember CBs can have a down draught or up draught effect for up to 20Nm around them.
That’s on top of wind shear.
UdoR wrote:
I would also assume that a typical SEP structurally withstands extreme turbulence even in CBs even when you suddenly enter an updraft or downdraft tube of say 50 knots vertical speed (around 25 m/s)
I agree it can probably withstand the turbulence itself, but the main problem is combined VMC / windshear / drafts which can easily trigger AP disconnect / disorientation / Vne exceed and therefore break the aircraft.
UdoR wrote:
To maintain precision on that: in the NTSB video that you cited above the Piper Cherokee 6 does not have a weather radar. It’s got an online weather service. That’s a significant difference, one could say that it is the very difference that might have led to the crash.
Exactly, the video makes it clear that radar via data services can have some delay which can induce a false sense of security when the (outdated by a few minutes) radar is overlaid on top of your moving map. Nothing beats onboard radar, which is what I referred to as one of the primary tools (sorry if it was unclear – onboard radars are indeed quite rare in GA).
I would say, if EMBED CB is forecast and intent to fly IMC without on-board radar, don’t go. If avoiding by a wide margin is possible (via VMC route or on-board radar), then maybe.
I reckon a number of TBM crashes were autopilot disconnect in IMC followed by pilot unable to hand fly due to poor currency.
But nobody can say it openly especially in type specific groups
In any IFR tourer you will be past Vne in seconds and then the Vs principle won’t protect you from a rapid disintegration.
maxbc wrote:
I believe there can be CBs without lightning (maybe even without heavy precipitation ?).
Yes I have seen one. Did look like a perfect CB with anvil etc. But no lightning, neither on board nor data linb from the ground. The same did apply for the radar close to nothing detected from the ground and the on board radar did not show anything either. But to be fair I think this was a short moment. 30min later it did have all those things. This is not very common but CB without lightning but with precipitation in them are quite more common.
I reckon a number of TBM crashes were autopilot disconnect in IMC followed by pilot unable to hand fly due to poor currency.
Which ones? Can you post the ASN links. Thanks 🙏
I flew on Friday and Saturday in the conditions as depicted before, forecast told embedded CB for Friday and isolated CB for Saturday. Both turned out to be true. On Friday weather was a stationary front-like weather system. I could see the CBs on the Golze ADL because of the precipitation and I stayed away from that (but still in solid IMC with light rain).
You probably know this already but just to make sure:
A full blown CB / +TSRA can emerge in the timeframe between Golze ADL / Garmin Connext updates. A lot happens in 20 minutes, sometimes in 10.
If you are in IMC, how do you assure to deviate from such buildups?
Snoopy wrote:
A full blown CB / +TSRA can emerge in the timeframe between Golze ADL / Garmin Connext updates. A lot happens in 20 minutes, sometimes in 10.
I’ve once been completely trapped in a cloud in a glider, it popped out of nowhere within seconds, and I was in the alps next to a mountainside, so 50% chance to leave the cloud on the wrong side
Yes I know something about weather. And doing so, I also know that extreme buildup speeds are related first order with extreme temperature gradients over altitude, and also with the amount of input energy. So one can foresee vertical speeds in a cloud mostly from the balloon data. I trained that extensively when I flew in glider competitions when I was young.
One can maybe draft some lines for go/no-go decisions. If there’s low energy available (e.g. high overcast layer shading the sun) and ok temperature gradient values, then even in a well developed cloud the updrafts will not be exaggerating.
I think the go/no-go decision will for still some further years have to be answered in each specific case.
By the way, there are some modern products available for glider pilots, that try to foresee the expected climb rates in thermals. This should be highly related to the hazardous potential of clouds. This is available in a map format indicating in colors (translates to a numerical value) and for a certain timeframe. I’m not very into it, I quit flying gliders before these tools came out. But they should be quite well developed by now.
@Sebastian_G would it be feasible to provide the weather receivers with such a map overlay of thermal activity, additionally to the “classics” precipitation, lightning strikes and cloud cover?
Maybe someone here knows of a good source of updraft data? Then I could try it out (as far as it works with a cell phone in the air) and see whether this data could be beneficial for IFR flights.
In these conditions you need to be VMC and avoid visually.
I have read accounts of pilots suddenly trapped by TS all around, but they posted them only on private sites, notably one Socata US one, now gone, whose membership used a blackball system 
so I am not going to try to invite them to post it here.
They survived… Just don’t try it with your spouse
