Peter wrote:
No, because a CB can build up in a few minutes.
That is that bloody problem. How do you foresee or plan a flight if there’s EMBD CB in the forecast?
You look at the cross-section and it tells you: mostly few, but also scattered or broken, but never overcast in the typical FL50 to FL80, in your case @par e.g. this one here for today 06:00 am:
But then how could you make sure to not fly into that single embedded CB?
I mean, typicaly there’s a low cloud layer, how can you fly on top to see what’s there and make sure to not hit something that develops between last weather check and takeoff?
UdoR wrote:
But then how could you make sure to not fly into that single embedded CB?
Weather radar is one of the primary tools. You may get away with online radar scans, but it’s not as recent / reliable / accurate. See for example :
par wrote:
Is it correct to assume that if there is no sferics(lightning) activity in a cloud, even if it’s a tall raining cloud it should be ok to go through, and I should expect maybe some light turbulence at worst?
I believe there can be CBs without lightning (maybe even without heavy precipitation ?). That does not mean you should go through or under. I would stay the hell away from any tall convective cloud, because the convection can be so insane it tears the aircraft apart in moments.
maxbc wrote:
I would stay the hell away from any tall convective cloud, because the convection can be so insane it tears the aircraft apart in moments.
While I’m not sure if it will tear the aircraft apart (outside the tropics), I’d concur that going info a TC or CB cloud is not the best strategy – updraughts of up to a few thousand feed per minute is going to be well, interesting.
It’s not hard to imagine how an aircraft can be torn apart: big updraft & wing gradient, Vno / Vne exceed, heavy turbulence → aircraft breaks apart. It’s not the updrafts per se, but the whole situation (especially the combination of speed and turbulence). I heard of such a situation with an aircraft around probably 120kts cruise speed reaching 250kt inside a CB (last transmitted data point – you can bet it’s not flyable for long after that).
maxbc wrote:
I would stay the hell away from any tall convective cloud, because the convection can be so insane it tears the aircraft apart in moments.
Well. It depends a lot on the energy in the cloud. Still most of the aircraft entering a CB get away without any damage, so it can’t be that deadly in general.
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) , which could be expected in a bigger CB. In particular the downdraft might really hurt if you’re not quite strapped down to the seat. But it should not do any harm to the aircraft, if there’s not more in it like hail and lightning. But it is quite uncomfortable.
As far as I know the greatest updraft of a CB was measured around 200 knots. But that’s in a supercell, where no one would fly into.
maxbc wrote:
Weather radar is one of the primary tools
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.
But turning back to the topic I found my Golze ADC very helpful for such kind of decisions. Used it for the first time last weekend and it really helps to stay ahead of the airplane. It’s enough to stay clear of the uncomfortable stuff. It is similar to online weather service with all the drawbacks involved that one should know exactly, but it gives a strategic picture to be able to avoid the regions of convection.
But that’s in a supercell, where no one would fly into.
In IMC, how would you know?
Still most of the aircraft entering a CB get away without any damage
I suggest looking up some lighting damage – previous posts can be found with a search.
Peter wrote:
In IMC, how would you know?
While still on ground, from actual weather. I wouldn’t start into a flight where a big cell is or is most probably to develop.
If in flight you need a weather service or weather radar to know about a big cell, but then you can fly around it.
What about an embedded cell? Radar IIRC picks up precipitation it doesn’t necessarily fare well with hail or snow or with thermal activity. It’s a different sort of instrument which picks up areas of electrical activity.
gallois wrote:
embedded cell
You mean for example a squall line, with several rain showers in a line and one embedded CB in it? You would see it with a lightning indicator. I would assume that any convective cloud that has dangerous turbulence also shows lightning activity.
A CB can go from no strikes to massive strikes in a minute or so. You will not usefully see that with any airborne system. The sferics data should show it but it needs internet, and will be too late for in-flight avoidance.
