Cumulus avoidance question

[legaleagle]

I have been flying for a little over 3 years now, with the commercial/instrument. But, all of it has been for business, friends, etc. I have not had a lot of actual IFR, which got me thinking about something that I see all the time, and an experience that I had in a 310 between BOS-ACY on the shark route.

Obviously the summer brings cumulus about every five feet. When we flew this route to ACY, we were about 8000 ft and were coming by a cumulus that was maybe another 4-6k higher, and we were flying in the evening, so the clouds were not really developing anymore. As we flew by the relatively small cloud, and on an IFR flight plan, the right wing caught the edge, and we got tossed pretty well at about 180 knots. Thus my query. Cumulus, by their very nature, have more than average lifting action. So, this I understand.

But, if you are flying a non-radar equipped airplane, non-stormscope, etc. and you are just flying along on a VFR day, say in the morning, before the clouds get over 10-12 thousand feet, I have always wondered what the maximum height cloud that you can fly through without any problem? I mean if you are flying at 8-15k during the mid to late morning, unless you want to weave back and forth, you have to fly through some of them. Obviously, the more mature, the further you want to stay away, but can you fly through a 3-4 thousand foot cloud before it develops? 1k? 2k? 7k? I mean you can fly through 10k of low pressure stagnant clouds all day long. But, when do you look at a cloud and say, can't go through it, because the lifting action is too great? I mean even little tiny cumulus look ominous. I am serious on this one. It has been a little bit of an irrational fear as I have not had an opportunity to get a lot of actual, and I am trying to conquer the fear, as I always do, by understanding it.

Always Learning,
CB

 

[Jedi_Cheese]

Cumulus isn't friendly. If it is actively building it is safer to stay away and weave around the cloud.

My rule of thumb is what is the weather doing? If the clouds are building and it looks like it is going to storm, it's safer to divert a little around larger clouds. If the clouds are stable and are layering out, then it is usually safe to go through. Also have an idea of how deep the cloud is so if you need to, you can climb out on top.

 

[Lead Sled]

CB...

I like your attitude - "Always Learning". May I make a recommendation? Get a hold of the book "Weather Flying" by Robert Buck. It and "Instrument Flying" by Taylor are "must reads" as far as I'm concerned. You will find them well woth the investment.

Lead Sled

 

[legaleagle]

Lead. I forgot I had it. Plus, it's packed up and heading to L.A. right now on the moving van. But, I read that about 4 years ago, and I completely forgot about it. I totally agree. It is a great book.

 

[legaleagle]

Excuse me, those are BOTH great books. Highly recommend everyone getting a used copy of it off of Amazon at the least.

 

[kc135ang]

In the air force you avoid CB's by 20nm at or above FL230 and 10nm below. I hope I recalled that corretly!

 

[414Flyer]

Avoid Cumulus? My current job is finding cumulous and flying thru it or very close to it

Yes lifting action and instability is what causes cumulous. If its just a cumulous with no storm yet, you can probably go thru fine, just get tossed around some.

Even when doing weather mod flying, we dont go, or at least arent supposed to go right into the main part of a t-cell however. Might go under, or pop flares into developing areas on the sides.

And I certainly wouldnt go into IMC with embedded tcells unless you had a radar.

 

[legaleagle]

Yeah, the 20 nm avoidance is correct for relatively mature T-cells, and I totally agree about IMC with imbedded. But, I just wanted to know about those little puffys. You know, the kind that move at about 10-15 knots, cover the entire southeast like pepperoni on a Dominos on any given day. Bases at about 4-6k and tops to about 10k or below.

Thanks,

CB

 

[hydroflyer]

Sometimes the heights of a cumulus can be deceiving as far as the turbulence potential in them. I am always looking at the edges of the clouds to determine how bumpy the ride might be. It the edge of the cloud appears rather sharp and well defined, like a chunk of broccoli, then chances are it will give you a real bad ride as it is "new" and in the developing stages. Look at the top part and if you look for a few seconds you will usually see upward movement in the developing cloud. I would avoid that one. I've had clouds that initially appear they would be below me, grow up just above my altitude as I get there and give me a heck of a ride for a few seconds. As the cloud looses the intense lifting, the sides will start to "feather" along the edges, but it doesn't mean they don't have turbulence. When those sharp edges disappear and blend away, and if you can see a hole in the cloud, then you likely won't get hit as hard. These are just a few things I personally use to give me a smoother ride around the daily cumulus.

 

[414Flyer]

If you are just asking about garden variety puffy cumulous, you should be just fine, just a few bumps if you go right thru there.

Regarding storm tops being crisp and defined, that is a good way to see a storm is not yet mature and is growing. That crisp and defined look is because the water is still in liquid form and has a lot of energy still left in it. Once it looks wispy, it is mostly turned to ice crystals and is in the dissipating stage. Doesnt neccessarily mean you want to fly thru it though.

 

[nosehair]

Yeah, the 20 nm avoidance is correct for relatively mature T-cells, and I totally agree about IMC with imbedded. But, I just wanted to know about those little puffys. You know, the kind that move at about 10-15 knots, cover the entire southeast like pepperoni on a Dominos on any given day. Bases at about 4-6k and tops to about 10k or below.

Thanks,

CB

No problem, man. Those little puffys will bump you around a bit, but are not really dangerous, yet. That is good experience to get comfortable in real thunderstorms which you may not be able to avoid later.

 

[na265]

If you can get Archie Tramells CD course on wx radar it is vry informative. It will answer some of your Q's.

 

[RJPilott]

and if you can see a hole in the cloud, then you likely won't get hit as hard. These are just a few things I personally use to give me a smoother ride around the daily cumulus.

ahhh... the sucker hole. those were good times.

 

[labbats]

Cumulus shouldn't be a worry for you. You'll just pop in and then right out of them, and I fly through them a lot with instrument students. Hitting some moderate turbulence in IMC, then breaking out into VFR again and again will hone your scan and give you a rest in between.

My best advice would be to find a seasoned pilot and ride along. See if any freight dogs or charter pilots will let you do that, and maybe fly a dead leg.

 

[414Flyer]

Cumulus shouldn't be a worry for you. You'll just pop in and then right out of them, and I fly through them a lot with instrument students. Hitting some moderate turbulence in IMC, then breaking out into VFR again and again will hone your scan and give you a rest in between.

My best advice would be to find a seasoned pilot and ride along. See if any freight dogs or charter pilots will let you do that, and maybe fly a dead leg.

Or go fly for Weather Modification for a season...

 

[Lead Sled]

When it comes to flying techniques, like I said in my first post, get your hands on Robert Buck's book "Weather Flying". It and "Instrument Flying" by Richard Taylor are, in my opinion, 2 must reads for people starting out.

You've read the book, now what? There was a time when things like weather flying, radar usage, etc. were passed down from senior, gray haired captain to "green" inexperienced copilots. Nowadays, many of us don't have that opportunity - we get our ratings and suddenly find ourselves in the left seat of a light airplane looking out the window at a thunder storm. The first rule of flying in thunderstorms is NEVER FLY IN THUNDERSTORMS. It's suicidal. You may get lucky a few times, but sooner or later, it will get you.

Always have a "Plan B" and a "Plan C". There's an old saying in aviation that says accidents occur when the pilot runs out of altitude, airspeed, and ideas at the same time. Always have a realistic, legitimate and viable backup plan and always have a realistic, legitimate and viable backup plan to your backup plan. (It sounds redundant, but it's not.) On a clear day, your backup plans might be simply, "We'll go to this airport and land and if that won't work we can go to that airport and land." On those days when the weather or fuel are real issues your backup plans become very critical. What will you do if the visibility or ceiling falls below your personal minimums? Where will you go? What airports are nearby? The 2nd backup plan (Plan C) is used to get you safely on the ground when your original plans have gone "south". It keeps you from getting in the dangerous position of having to make up the rules as you go. That's the way many pilots have gotten themselves into serious trouble. Always have two workable and realistic alternative plans. When things get tough, the peace of mind they provide is priceless.

Remember, when it comes to T-Storms the word is AVOIDENCE. Radar and spherics detectors (Stormscopes, et al) are used to AVOID them NOT for penetration. Even it you have all of the latest whistles and bells; nothing replaces the need to look out the window. As far as I'm concerned, the best way to avoid them is visually - either down low, below the clouds, or up high. Flying IMC in areas of convective activity without a Stormscope and/or Radar is going to, at some point, make for a very interesting afternoon. By the way, don't believe it when you hear guys say that those little "popcorn cu's" can't bite - they sure can. It's just that in some parts of the country they are often pretty benign. In other parts of the country you can loosen your dental fillings in them. The best way that I know of to insure a good ride is to maximuze your time at altitude and above cloud base and to use a Stormscope to avoid the areas of electrical discharge that are associated with significant convective activity.

I'm fortunate to fly aircraft that are typically equipped with both color weather radar and Stormscopes. It does make things a little easier (Provided you know how to properly use and interpret the weather radar - many guys don't.) If you're flying aircraft with both types of equipment you typically use the Stormscope to decide what you're going to deviate around and you use the radar for the actual deviation, its resolution is much better. Having both systems is by far the best and it also provides you with some redundancy. The absolute best combination is a Stormscope matched with one of the Vertical Profile radars. It makes interpreting what you're seeing on the display silly simple.

But, like I said in my first post, go get and read the book Weather Flying then we can talk some more.



Lead Sled

 

[legaleagle]

Lead,

I appreciate the very detailed response! I have to say the 53 years is pretty impressive.

 

[Lead Sled]

Lead,

I appreciate the very detailed response! I have to say the 53 years is pretty impressive.

That's only how long I've been breathing. I've only been flying 38 if those years. I guess that I misunderstood the question.

Lead Sled

 

[Tweetdrvr]

Aside from the "looks like broccoli or cauliflower" or "growing like a weed in the Texas sun" techniques another thing to consider is the freezing level. I will deviate around anything that meets the cauliflower/weed criteria especially if it is within 2000 feet or so from the freezing level. All the ingredients for a thunderstorm are present, they just haven't started falling from the bottom of it yet.

Since I fly a plane without radar and stormscope, these rules of thumb come in pretty handy.

Fly Safe!