Bumps and Thunderstorms

spiderweb

spiderweb

Final Approach
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Ben
Today's trip from FDK to FRG was great, and I wouldn't have done it IFR without the G1000 and Nexrad. I do have a question, though. I was in and out of CU and TCU, and keeping well away from pop-up thunderstorms, but I did feel a bit nervous about some of those bumps. When I would pop out, I would sometimes look up and see a buildup to my right or left which seemed to go quite high (maybe as high as 20,000'). That made gave me pause.

What is the proper thing to do in this case? I attempted to deviate to the left or right as needed (with ATC approval) and just stay out. But that wasn't always possible, of course. I had no strikes or even any green where I was.

So my question is, is it possible that a 20,000' TCU would not have any precip (at least that would be shown on radar or Nexrad)? I know there would be turbulence, but I guess I am asking this: if there's nothing on radar, and no strikes, is it safe to penetrate? Once in, I didn't know the cloud tops.

(BTW, my wife was enjoying it!)

Thanks in advance!
 
You don't need lightning or precipitation to have severe turbulence for GA aircraft.
 
Ben, that's the real question, isn't it?

If all your intel is negative, I'd pop in and out near Vman. But it's a rough ride. I prefer O2 and on top of the embed, so that I am looking at a couple of 3-Mile Island Cu sticking out of the deck below. Then I know plainly what to do.....
 
I think some of my worst turbulence in IMC has been in clouds without any precip - and definitely not any lightning strikes.
 
spiderweb said:
So my question is, is it possible that a 20,000' TCU would not have any precip (at least that would be shown on radar or Nexrad)? I know there would be turbulence, but I guess I am asking this: if there's nothing on radar, and no strikes, is it safe to penetrate?
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That question reminds me of when I first started to fly with onboard radar. No echoes, must not be anything bad in that cloud! Oops I guess that was wrong as everything starts flying around the airplane...
 
bbchien said:
Ben, that's the real question, isn't it?

If all your intel is negative, I'd pop in and out near Vman. But it's a rough ride. I prefer O2 and on top of the embed, so that I am looking at a couple of 3-Mile Island Cu sticking out of the deck below. Then I know plainly what to do.....
Click to expand...

I see what you mean. And actually, I did slow to Vman. It wasn't that bumpy, but I might have been lucky (or smart), by trying to avoid bad stuff before going in. Definitely no red, yellow, or green where I was. I also asked for 9,000, but was denied. Not sure how much of an advantage it would have been.
 
spiderweb said:
So my question is, is it possible that a 20,000' TCU would not have any precip (at least that would be shown on radar or Nexrad)? I know there would be turbulence, but I guess I am asking this: if there's nothing on radar, and no strikes, is it safe to penetrate?
Click to expand...

Ben,

I once had a bit of a scare that directly relates. I was doing the same thing, popping in and out of a broken layer at 9,000 and looking up to see if there were any TCU's. There was no forecast for TSRA, which is why I was there in the first place.

Well, one of those clouds decided to become upwardly mobile. With hardly a bump, my VSI flopped from zero to pegged at +2000 FPM. I pulled power to idle and nosed over to try to counteract it, but I was still pegged. I was talking to GRB approach at the time, and I let them know that I was in an uncontrolled climb. I did the ol' 180, but I was up around 13,000 when I got out of the updraft. Oh, and I had a 496 aboard that showed nothing.

After I was out of the updraft I called Green Bay again and asked if they were painting anything on radar. Nope.

After I'd had a chance to think about it, I realized that there is NOTHING that can keep you from running into a building thunderstorm - The first sign of it that's detectable by means other than Bruce's on-top Mark I eyeball is when the lightning begins, which would be detectable on a stormscope. Radar, be it on-board radar or ATC radar, will not detect anything until the rain begins at the beginning of the mature phase. And, it won't show up on your Nexrad datalink for another 5-10 minutes after that.

I wondered if I'd been utterly stupid somehow... And then I saw a story that was pretty much exactly identical except for the time and place in Ken Ibold's book ("Defying Gravity" - highly recommended, BTW), so I know I'm not the only one.

So... Think through this scenario now from the comfort of your chair.

(BTW, my wife was enjoying it!)
Click to expand...

Excellent! :)
 
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spiderweb said:
I see what you mean. And actually, I did slow to Vman. It wasn't that bumpy, but I might have been lucky (or smart), by trying to avoid bad stuff before going in. Definitely no red, yellow, or green where I was. I also asked for 9,000, but was denied. Not sure how much of an advantage it would have been.
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In the midwest we say, "it's always clear about 10,000 feet".....which is inaccurate. Some times you need 18,000 and Kent will attest to that.
 
Assuming certain conditions, [small acft incapable of topping clouds, VFR conditions with a decent ceiling and vis], would going VFR be better? At least you would be below potentialy dangerous clouds and not in them and perhaps better able to see the buildups.
 
Kent, certain types of Doppler RADAR can see that much air moving in relation to the aircraft. No one's yet attempted to scale it down in size or cost for aircraft, that I know of yet.

Difficult... "wind profilers" and the like use large UHF arrays pointed straight up, for example. They're not using microwaves so the antenna gain and other issues aren't trivial.

Fiscally difficult too. Unless it could be crammed in the nose of an airliner first, and there's already another radar array taking up a bunch of space up there in most of them, it'd never be feasible to scale it down to GA nor sell in tiny quantity to make up the development costs.

But a "airborne windshear/wind profiler" RADAR is possible today... There's just not enough of a market for it. Needs pitch-men/women and a big pile of cash to make it a reality as far as an airborne weather tool goes.

Military applications for UHF RADAR have always been easier since they could use arrays on the sides/skin of the aircraft aimed 90 degrees off-course. For this application the array would probably have to radiate forward and there's just no room. Maybe leading edges with arrays bonded in them and receiver in the nose?

Going the other direction up closer to the first RF resonant frequency of oxygen molecules (around 200 GHz if I remember my conversation with a friend who holds a number of communications world records *above* 200 GHz - he had to skip one band of frequencies since all that happens when the transmitter is on is that you instantly heat up the air in front of the antenna a little bit)... Might yield a commercially viable product if the development costs could be handled. Probably the type of thing that'd spin out of other funky stuff DARPA has been working on for directed crowd/battlefield control of combatants via big transmitters and lots of "discomfort").

Interesting nut to crack for some crack team, but the cost/benefit probably doesn't ultimately work out yet to have a "turbulence warning" on aircraft. Maybe someday.
 
denverpilot said:
Kent, certain types of Doppler RADAR can see that much air moving in relation to the aircraft. No one's yet attempted to scale it down in size or cost for aircraft, that I know of yet.

Difficult... "wind profilers" and the like use large UHF arrays pointed straight up, for example. They're not using microwaves so the antenna gain and other issues aren't trivial.

Fiscally difficult too. Unless it could be crammed in the nose of an airliner first, and there's already another radar array taking up a bunch of space up there in most of them, it'd never be feasible to scale it down to GA nor sell in tiny quantity to make up the development costs.

But a "airborne windshear/wind profiler" RADAR is possible today... There's just not enough of a market for it. Needs pitch-men/women and a big pile of cash to make it a reality as far as an airborne weather tool goes.

Military applications for UHF RADAR have always been easier since they could use arrays on the sides/skin of the aircraft aimed 90 degrees off-course. For this application the array would probably have to radiate forward and there's just no room. Maybe leading edges with arrays bonded in them and receiver in the nose?

Going the other direction up closer to the first RF resonant frequency of oxygen molecules (around 200 GHz if I remember my conversation with a friend who holds a number of communications world records *above* 200 GHz - he had to skip one band of frequencies since all that happens when the transmitter is on is that you instantly heat up the air in front of the antenna a little bit)... Might yield a commercially viable product if the development costs could be handled. Probably the type of thing that'd spin out of other funky stuff DARPA has been working on for directed crowd/battlefield control of combatants via big transmitters and lots of "discomfort").

Interesting nut to crack for some crack team, but the cost/benefit probably doesn't ultimately work out yet to have a "turbulence warning" on aircraft. Maybe someday.
Click to expand...

Actually Rockwell/Collins made (or still makes) an onboard radar that incorporates a limited Doppler capability. Unlike NEXRAD, it doesn't sense and display the relative velocity of the droplets in a plan view, instead it simply shows areas where there's a measurable variation in the frequency of the returned signal. IOW there's no direction or relative velocity shown just that there is some sort of movement towards or away from the airplane. IIRC those areas were depicted with magenta coloring.
 
This is a great question with great responses -- I wish I could have read before my first IFR XC with family aboard.

:mad:

I put the needles right in the middle and plowed right though three consecutive 11 AM on a hot August Central Pennsylvania holy crap towering CU that extended up past 17k.

NY center chided me for being 300' above assigned altitude -- I was power to near idle and pushing and we were still getting shot straight up at over 1500 FPM.

It was not fun.

Center wouldn't allow higher but did allow deviations -- which I finally figured out was the smart thing to do.

:rolleyes2:

That stuff wasn't covered in my IR training (even though the majority of my training was in actual). There's a big difference between mid-spring stratus and mid summer Cumulus.
 
Even when IFR, I don't fly through clouds I don't have to. When on an airway, remember how wide that thing is and don't be afraid to deviate the .25 or .50 NM to go around a TCU. When I make a small deviation like that I don't normally tell ATC.

When I find I have to deviate a wider distance (because of a line of TCU) then I ask ATC for deviations and give them the direction and distance I think I'm going to need.
So far I've rarely been denied.
 
bbchien said:
so that I am looking at a couple of 3-Mile Island Cu sticking out of the deck below. Then I know plainly what to do.....
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What is a 3-Mile Island Cu - from a long term Babcock & Wilcox person who spent some time at the island immediately after the accident.
 
bbchien said:
In the midwest we say, "it's always clear about 10,000 feet".....which is inaccurate. Some times you need 18,000 and Kent will attest to that.
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Yup. It's not unusual to see FA's forecasting tops to FL200 even without significant convective activity around here. That said, when I see that the PIREPS often indicate tops in the 16-18 range, but such is the nature of forecasts.
 
denverpilot said:
Kent, certain types of Doppler RADAR can see that much air moving in relation to the aircraft. No one's yet attempted to scale it down in size or cost for aircraft, that I know of yet.
Click to expand...

So, put another way:

flyingcheesehead said:
there is NOTHING that can keep you from running into a building thunderstorm
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;) :D

I'm not saying we don't have the technology to do such a thing - It's just not on anyone's airplane yet. If you fly IFR, sooner or later you're gonna find yourself in an upwardly mobile cloud. Think about how you'll deal with it now, not when it happens.
 
the few guys who have (intentionally or not) gone soaring up into cumulus clouds have often reported fantastic climb rates. While the thermal may have been 500 or 800 feet per minute below cloudbase, with the right conditions the latent heat of condensation accelerates the updraft to 2-3000 fpm. that 20-30 knots of wind, going up.

stay out of the cu. ATC in the midwest is always good about granting "deviations left and right of course as necessary for buildups" most of the time you can stay well within IFR standards without the clearance as the diameter of the cu is rarely more than a mile.
 
flyingcheesehead said:
So, put another way:



;) :D

I'm not saying we don't have the technology to do such a thing - It's just not on anyone's airplane yet. If you fly IFR, sooner or later you're gonna find yourself in an upwardly mobile cloud. Think about how you'll deal with it now, not when it happens.
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And think about how that might be different with passengers. My concern was with my wife. I've been in those up and downdrafts plenty of times, but it can be shocking to a non-pilot. Add into the mix your spouse who is on the fence about flying in "small planes," and you have more anxiety.

I found it funny that this past time (which was really only moderately bumpy), my wife stayed asleep!
 
spiderweb said:
And think about how that might be different with passengers. My concern was with my wife. I've been in those up and downdrafts plenty of times, but it can be shocking to a non-pilot.
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I'm not talking mere up and downdrafts - I'm talking building CU's which result in an uncontrollable climb even with the power to idle and the nose pushed over to near Vne. I gained around 4,000 feet before I could get out of it. Oddly enough, it was the smoothest part of the whole flight - I'd been getting average or slightly above average summer bumpiness for the whole flight until I flew into that cloud. Once I was in the cloud it was smooth but the next thing I knew the VSI did a backflip and the altimeter began winding up like it was attached to a power drill instead of a static port.

Would I like it to happen again? Hell no. Will it? Probably. I've only been flying for about 8 years and 900 hours, and I hope I have much more than that still left in me.
 
And don't forget...what goes up must come down. That applies to air. Meaning you can encounter severe downdrafts inside of and in the clear air around buildups.
 
I think the 3-mile island comment is in reference to a mushroom cloud and it's roiling growth pattern, in spite of the fact that the 3 mile island incident, even if it had gotten worse, wouldn't have resulted in a mushroom cloud.
 
spiderweb said:
So my question is, is it possible that a 20,000' TCU would not have any precip (at least that would be shown on radar or Nexrad)? I know there would be turbulence, but I guess I am asking this: if there's nothing on radar, and no strikes, is it safe to penetrate?
Click to expand...

Yes.
No.

Just 'cause it's not spitting rain, don't mean it's a friendly neighborhood.

Consider this -- ever flown through a stratus deck? Spittin' rain?? Nice smooth ride? Precipitation does not equal turbulence.

Cumulus means expandin', and expandin' means bumpin (to steal a phrase from Nathan Bedford Forrest).
 
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