flying through cb(s)
 

I am reading up on CB and how it affects flights. But I can't seem to find what kind of equipment or aids we have to navigate safely in those conditions.

I assume that it would be best to steer around them, but when there is no choice, what do you guys do?

Aside from radar and several pairs of eyes in the cockpit, what other equipment are available on the plane to fly through CBs?

thanks
e.

Flying through CB's is obviously never a good situation.
The best thing to do (certainly from what I have been told on the 737) is to increase the WX radar range and navigate round them, of course advising ATC at the time. You have to increase the range on the radar, there is nothing like dodging one small one, but not seeing a massive one just off screen straight in your path. This of course applies to enroute CB's, now CB's on final approach......... :uhoh:

The 737NG has something called PWS (predictive windshear), it notifys the pilots (below 2,300ft I believe) of any windshear ahead of the aircraft. I have not seen this in operation, apart from a demonstration during my type rating.

Eyes won't help you a lot when flying through a CB--you won't be able to see anything clear in the cockpit due to turbulance :}
You should never fly through a cb with an airliner...at cruise it's maybe easier to avoid them as you can plan well ahead. During take-off or landing it may be harder to avoid,but at least you can try to avoid the center of the TS,delay your take-off or hold untill the CB pass the field.
Most of the CB's are moving fast..remember once getting the ATIS with CAVOK (perfect) ,and next one,in about 20 min was +TS (heavy thunderstorm) , so we just reduced speed at min ,and in about 15 min the weather was ok again.
About Cb encouter ,well, i've had once a faulty radar,I think ,cause it didn't show a thing ,while we were experiencing severe turbulance ,with vertical speeds ranging from -2000 feet/min to +1500 feet/min (we were descending in clouds ).A lot of lightning around the plane ,also static on the windshields...I've had bruises from the seatbelts that time.
Ans one friend of mine lost in a blink 7000 feet while trying to pass bellow a high base CB in Africa ,at around FL100.
So,they are not something to mess around with,no matter what gizmos you have on board.

There is ALWAYS a choice! It might range from a 180 deg turn to staying on the ground in the first place.

DON'T FLY THROUGH CBs!

DON'T FLY THROUGH CBs!
Although aircraft are designed and built to withstand an inadvertent entry to cbs, such situations should be avoided. Personal experience during planned testing involved a minor (20 sec) flight in the edge of a cb. In this period, flying at turbulence speed, the limits of certified normal-acceleration (+ & -) were experienced, including stick shake. The flight brief was to maintain constant attitude, however with the level of buffet, and rapid reversals in pitch, roll and yaw, all that could be accomplished was to hold everything in the centre.
During other tests adjacent to cbs, the cloud build-up was at least 3000 ft/min and possible as high as 6000 ft/min; so don’t think that you can out-climb the cloud formation. Also, beware of flying through or just under the anvil. Although the turbulence levels are low, often severe-icing conditions exist, including super cooled ‘liquid’ water. Generally the advice is to avoid cbs by a minimum of 5nm; however, to provide a margin for errors in detection (different radar systems and their responses in these conditions), rapid cloud formation and movement, anvil conditions, and misjudgment, then my experience suggests that aiming for a 15nm miss distance is safer.

Aircraft most certainly are NOT designed to withstand entry into cumulonimbus storms. I agree with the remainder of your statement.

Right now my sole function is flying turbojet airplanes into storms for weather research. I generally fly a Lear 35A into convective weather to study it, sample it, and in some cases, experiment with modifying it.

DO NOT FLY INTO THE STORM!!!

Think of the thunderstorm as the Finger of God. You're a gnat. There are forces inside more powerful than what you think they will be. Scott Crossfield, a well known name in flight test and aviation history, was killed not long ago when he flew through a thunderstorm; his aircraft broke up and he lost his life. The storm is not a respecter of persons; you may fly through one a dozen times or a hundred times and one the next one, it will take you. Don't put yourself, your aircraft, or your passengers or company in that position.

Weather radar is only partially able to see what's out there. Frozen precipitation doesn't paint well at all; dry hail, dry snow, ice, all can be invisible to radar. We hail, slush, graupel, and other features containing at least some liquid water are visible, but can be very misleading. What you think is a level 1 return or even a blank spot on the radar, can hide some very nasty surprises. Hail may not show up at all, and it can be very large, very fast, and do an increadible amount of damage, even far from a cell. Miles away.

Up and downdrafts have been recorded in excess of 12,000 fpm in the cells. Going into a sheer zone between such changes means a 24,000 fpm vertical shear, and your aircraft was most definitely not designed for that.

Ice buildup can be very rapid, and not at all where you expect it. Supercooled water between -10 and plus several degrees can form extremely rapidly; I've picked up three inches of ice in very short periods when penetrating cells, and others I fly with have experienced severe engine damage as a result of rapid ice buildup and shedding into intakes, etc. Even with everything working. Even when the last few penetrations through the same cell were uneventful. Even when it doesn't look so bad on radar. Even when a team of scientists are guiding the flight by radio, watching you on some very sophisticated radar...even with a team of scientists on board and a full suite of electronic sensors giving you detailed analysis of the storm and atmospherics as you go through.

When YOU penetrate a Cb, you don't have any of that going for you. What you have going for you is guesswork and luck, and that's no way to live.

Autopilot function may become impossible in convective weather. You're back to handflying it. If you're getting slammed, you may not be able to clearly see your instruments. You may be subject to injury. Your headset quite possibly won't even stay on your head. If you're below maneuvering speed, as you should be, you may find yourself stalling repeatedly. We often get the stick shaker and even the pusher when it gets rough, and we stay out of most of the serious weather.

As SP noted, weather can come from below with rapidity. When I start working a cell, I often make a pass through the upper parts of it first, and start making passes through the rising turrets alongside the main tower. Fresh starts are of the greatest interest, but these are often rising at thousands of feet per minute. Even if the convective activity at the surface isn't that great, the vertical velocity of rising air is cumulative. If a parcel of air rising at 300 fpm bumps into another parcel of air moving at 200 fpm, it now rises at 500 fpm, and soon bumps into more air rising at 400 fpm...now it's 900 fpm and rising. You get the idea. As this happens relative humidity in the parcel of air climbs, temperatures drop, and the parcel can remain liquid for a considerable time and well above normal freezing altitudes. On the same storm that 12,000 fpm vertical was located, the temp with liquid water was found at -38 C. High, wet, rough.

On another flight, what appeared to be a normal entry into a rapidly rising white puffy cumulus cloud turned out to be hail and weather that engulfed the ariplane, causing over three hundred fifty thousand dollars in damage to engine inlets, nacelles, damaged or destroyed fan blades, destroyed leading edges, radome, etc. In seconds. That with the penetration initiated with radar tilted down considerably to view the cell; it rose and enveloped the airplane quickly and with a vengence. You don't want to be there at a time like that.

When passing from one level of convective activity to another, inside the weather, the changes may appear subtle, but the results encountered (and the aircraft reactions) may be markedly diverse. A level 1 green return with speckles of yellow, suggesting level 2, appears benign sometimes. Almost calm. Elements of graupel and rapid ice buildup give way to dryness, and nothing, and then suddenly heavy rain. Doesn't appear like much on radar, but it's there, and on the second pass after a quick turn to re-enter the cell from the opposite direction, the character has grown ugly. Ice builds so rapidly it can't be shed. Noise, lightening, thunder we can hear, and then lightening strikes. Is this the time you want to lose your radar because of an electrical discharge or lightening strike? How about your isntruments, radios, or instrument displays?

We get frequent precipitation static such that one we're in the weather, we're not talking to anyone; we can't. The radios just hiss and growl, and at night we can see it corresponding to sporadic buildups of corona and St. Elmo's fire. Occasionally a discharge occurs; completely blinding if you happen to be looking out at a tip tank for ice or to see the St. Elmo's at the time. A few weeks ago it burned holes through our elevator, and melted pits down one tip tank, blew out static wicks, and put burns on the radome. In times past I've seen it burn holes through elevators, flaps, propellers, and melt pitot tubes, ice detectors, and AoA vanes in varying degrees. You don't want that.

Take great pains to avoid weather. What is inside, you shoudn't experience. There are things inside which can hurt you, disorient you, sap your performance, break your airplane, tumble your gyros, leave you covered in ice, and pull you to pieces. Not every storm is like that, but do you really want to pick and choose?

Thanks for sharing your experience SNS3Guppy :D

Sounds like you do some interesting flying, gotta save you some bucks going to Space Mountains and the like ;)

My little experience dates a few years ago in the MD80, flying thru a smallish undetected CB, leading to some frightening turbulence and hail, and then the replacement of our radome as well as the engine inlets... no desire for a repeat, thanks!

I think SNS3Guppy's post should be made a sticky. Well said by someone with more experience than I personally would like to achieve! I'm more than happy to take his word for it.:D

Yep, there was...resign. As a young F/O I nearly did. I've told this before, but it's worth repeating I guess.

Viscount. No radar fitted. LHR to Spain

Night after night being flashed and banged at. No communication due to static. No chance of conversation due hail noise on screens.

One particulary bad night we took 45 mins on one 20 min leg. Total flight nearly an hour longer than planned.

Thrown below Min Safety over the Pyrenees. Repeated full range application of controls. Horizon bar off the scene...top and bottom, time and time again. Passengers unstrapping to kneel and prey. Sick and blood dripping from the ceiling.

When we got there the captain told me to hurry to do the turnround cos we were late! I finally persuaded him to let me re-plan over Marseilles. As mentioned above, these things move quickly, and in no time we were in it again.

After another thrashing we popped out of cloud into post frontal clear air. We could see the lights of Paris from 200 miles away. Skipper told me to fly cos he was knakkerd. He pushed a cigarette into his mouth and struck his Zippo. At that precise second, we were struck by a single bolt which blew a 4" hole in the starboard wing. I had seen it coming. It popped out of the higher region of a vast Chinese lantern that was way behind us. Zig Zagged up for what must have been a mile...then came streight for our wing...yep, like a finger of God. The burn went round the fuel bags and came out in line with the top hole.

To this day I have the clearest memory of the skipper's face, his eyes bulging in his ashen face which was illuminated by the little flame from the Zippo. "Did I do that?" type of expression.

Some amazing experiences potrayed here.I have the greatest respect for CB's, when I'm flying I like to see them, but as far away from us as possible.

Micro Bursts, Ice , hail, uncontrolled vertical speed deviations, tornadoes....... enough reasons to stay clear? :\

I have so much respect for the regional pilots in the US who dodge super cells during Mar-Jun over tornado alley, I would not have the stomach for it.

There are OLD pilots and BOLD pilots but no OLD BOLD pilots
fly safe everybody

SNS3Guppy re your statement – “Aircraft most certainly are not designed to withstand entry into cumulonimbus storms”.
I suggest that a more circumspect approach is required.
We may have differences in our opinions or in the use of the wording between ‘entry into’ and ‘withstanding inadvertent entry’.
There could also be differences in the design and certification levels of the aircraft being considered. A light aircraft or bisjet might not meet the structural requirements of FAR/JAR 25 - Large Commercial Aircraft; the aircraft which I flew did (but it was still damaged).
In my experience I have yet to see a commercial aircraft flight manual which prohibits fight into cbs i.e. a restriction requiring avoidance ‘at all cost or else’. This suggests that those aircraft have at least some protection against inadvertent cb entry, but there again not all cbs are equal! Similarly this does not imply that flight into cbs should be done.
A major point of my response is to avoid leaving some pilots with the belief that an inadvertent entry into a cb will be fatal. It certainly will be hazardous and the situation should be avoided, but provided the manufacturer’s advice is followed the aircraft should remain structurally sound albeit slightly dented.
Aircraft that do not survive cbs might have been handled incorrectly, thus placing them beyond design limits, or in some circumstance the aircraft could already be structurally weak. Examples of the latter can be found in reports of turboprop accidents in S America; structural inspections were not completed – post accident inspection identified pre existing wing cracks.
This topic is a good example of Threat and Error Management. The threats from a cb should be identified and avoided, but if through error – failure to identify, equipment failure, or human involvement, then the resultant (inadvertent cb entry) must be managed. This can be done by following AFM advice which is designed to mitigate (not eliminate) the risk of the threat and/or error.

As a reminder, this is what might happen:
http://flightlevel.20megsfree.com/

Oh and safetypee; it should be drilled to avoid Cbs. Remember the F28 losing a wing while circumnavigating?
http://aviation-safety.net/database/record.php?id=19811006-0〈=en
I still have to find the guy that can teach me which Cb will be fatal and which one not.

In my experience, the sheer belt-slapping, spar-snapping peaks of turbulence have come in clear air. The flight system a vertical blur and hands flailing about trying to grab at the power and the brakes have happened with not a cloud in sight.

When this hits wing resonance, they really do start to twang.

One time we put ten miles between us and the core of the CB which was way below us. We could see it on radar and flashing in stratus below. Suddenly we descended in violent lumps just like crashing down concrete stairs 1,000 feet a step. My jacket swung on its hook and almost hit the roof. No record of negative g on our old BAC1-11, but it was more than a little.

I fear that often the damage done to aircraft is caused by attempts to correct unusual attitudes. I'll risk stating the obvious, but it's vital not to be blinded by the flashes, and also vital not to try to correct a severe upset too quickly.

I'll stop now before I'm tempted to say what I think about the removal of good old tied-gyro turn indicators.

Quite. Doubtless you've also not seen a commercial aircraft flight manual which specifically prohibits flight directly in to the face of a granite wall...yet somehow we all know it's a stupid thing to do.

Neither is the aircraft designed for that event, neither is it designed, nor intended, to be flown into a cumulonimbus cloud.

Part 25 makes you no gaurantees.

safetypee, If you would like some sobering reading re jet transports and CB's google up

Northwest Airlines Boeing 720 N724US 12th Feb 1963
Braniff BAC-111 N1553 6th Aug 1966
Southern Airways DC-9 N1335U 4th April 1977

Interesting that WWII US Army Air Corps met books had reference that a crews inability to fly successfully through CB's was down to lack of skill. Gann in his "Fate Is The Hunter" makes reference to how airline crews of his day (30's and 40's) dealt with CB's. Makes for harrowing reading and explains perhaps both the coast to coast litter of bent airline aluminium in the US during those years and the page upon page of names to whom memory his book is dedicated.

All my respects to you SNS3Guppy ,you are doing an incredible job. I don't know if I'll have the gut to do it.I did all kind of flights ,but I have a deep respect for weather and I don't know if i'll enter it voluntarily.Unless flying a military high performance jet,maybe..
Energie ,SNS3 is one 'device' i'd like having on my plane when flying around Cb's:ok:

In the 'ole piston airliners of yesteryear, it was more or less common practise to fly thru CB's, if they couldn't be avoided.
Slow to maneuvering speed, and press on.
Then came the early jets.
Up high, they went...and then, just like in the old days, slowed way down, and pressed on...straight into the weather.
Enter the classic jet upset.
On the way down, engines chucked right off the pylon...try explaining this to the fleet manager.:uhoh: :uhoh: :uhoh:
Then folks got wise.
They went around the nasty weather.

Gee, what a surprise....:ugh:

The difference between a CB and a granite wall is that there's only one severity of granite wall. CBs come in a full range, from those in which the Bergeron process is just starting to produce rain, to those that break aeroplanes just for fun.

I'm truly amazed by the responses here -- I can only imagine that you all stay on the ground in spring and summer if you religiously avoid CBs. The key to safe flight is in avoiding the flight conditions associated with convective weather that are going to kill you. That means working out which CBs you can fly in and which you can't.

Bookworm

I realise that you are very knowledgable in the area of aircraft design.

Please would you confirm what level of pilot's license you hold.

Many thanks

F3G

Bookworm permit me to doubt that you have ever been inside a real CB :=
You might have been close to or dodged some, flown in between some others, but I seriously doubt that you will willingly flew into any kind of CB (in which case I sure never want to be in any kind of craft in your company...) :rolleyes:

And yes, I think most of us still manage to operate regularly and safely during spring and fall convective weather, "religiously" avoiding CBs by flying between them, no big deal, just daily bread!

I think that's the whole point F4F. You talk about a "real CB". Technically a cumulonimbus is a cumulus that has started to glaciate i.e. it has lost its cauliflower-like appearance and started to look wispy at the top, indicating a phase change from water to ice. It doesn't even have to be associated with significant precipitation at that stage. In winter their tops can be really quite low. Take a look at the Cloud Atlas description.

I have certainly flown clouds of type 3, and I would be amazed if you hadn't, because if they're embedded then you won't tell them apart from the rest of the cloud you're flying through. The radar just shows you precipitation, not CBs as such, and the precip may be very light, none in parts. While (despite the nimbus) cumulonimbus is not strictly necessary for convective precipitation, most convective precipitation comes from CBs. Can you really tell me that you've not flown through cloud producing convective precipitation?

I've flown through some CBs that I'd rather not have, and I've avoided lots that I was not going to go within many miles of -- what you would rightly call "real CBs". But that avoidance was not on the basis of whether or not they were CBs, but the precipitation, vertical extent etc.

The point I'm making is slightly deeper than scoring a cheap point on a meterological definition. There is a continuous progression from innocent little cumulus to mean SOB thunderstorm. At no point does the cloud put a sign up on its edge saying "Don't fly through me I'm too nasty now". ;) Instead we all have to build an understanding of the danger signs and the criteria we will use for avoidance need to me more subtle than "is it a CB?".

Tell ya what F3G, you start with your qualifications in cloud physics... ;)

So what sort of cbs are we talking about? European cbs, Equatorial cbs, central USA cbs?

To paraphrase George Orwell "all cbs are equal, but some cbs are more equal than others!"

bookworm: beat me to it. like your response!

Somewhere in my house I have a United States Army Air Force manual titled "Weather Flying" that belonged to my father that he kept from when he was in basic flight training dated 1941.

Although I must paraphrase here I clearly remember some of the statements in this manual convening Thunderstorm penetration. It went something like this;

1. When approaching a line of heavy thunderstorms fly toward the area of heaviest rain.

2. Avoid areas with frequent and heavy lighting.

3. Fly aircraft at reduced airspeed.

4. Lower seat to lowest position possible.

5. Turn all cockpit lights to full bright.

6. Secure all lose items in cockpit and cabin.

8. If possible restrict aircraft altitude to below the freezing temperate level.

9. Enter thunderstorm at lowest altitude while still keeping a safe level above terrain.


Then the manual went on to make statements such as, safe flight in thunderstorm can be completed, try to avoid green clouds as that is an indication of hail, expect heavy water leakage into cockpit, etc

Well I can certainly attest to the water leaking into the cockpit from my old DC-3 days, and not even close to any thunderstorm, just good rain.

When I first started my aviation career as a pilot I flew with a lot of World War II era pilots. As 411A said, until the jet-upset accidents started happening most of those guys considered thunderstorms just another cloud.

I also flew thunderstorm research many, many years ago in a (believe it or not) Twin Comanche. However, I never actually penetrated any cells, not on purpose anyway, I flew around the bases recording data and firing off flares. It was a study conducted by the US Air Force, NOAA and the University of Oklahoma. The aircraft used were, Twin Comanche (me), Cessna 401, T-28, F4 and a modified B-57 Canberra. There was a F-100 used as well, however, it flew through a heavy area of hail at very high speed and although the pilot was able to land the aircraft it was written off.

Trust me, we have thunderstorm super-cells in Oklahoma that top FL60.0 +. One does not mess with them. Matter of fact one should not mess with any thunderstorm.

Bookworm

As a PPL I was wondering whether your experience was from theory or experience.

Now I am just going to put you on my ignore list, as the true professionals don't make sarky remarks like that.

Take this exact view but from the deck outside. 1,250' amsl.

http://img.photobucket.com/albums/v7...e/DSCF0323.jpg

Now imagine a dark night with a clear view of the stars. In the distance we watched the most fantastic display of vast and very tall Chinese lanterns flashing away over most of the horizon you can see in the pic. It was stunning and very beautiful...but something was wrong: there was not the slightest sound.

I was really puzzled and looked at the radar channel on T/V which was live. They were 300 miles away well north or Dallas!

Thank you for your post con-pilot.
Cheers!

World's Largest distributor of used aircraft parts - Thunderstorms.

None of you mentioned the turbulence detection feature of the modern Wx radars. It won't detect turb where there's no moisture, but will do a fine job of highlighting areas of moderate and greater turb in the presense of precip, out to 50-60 miles.

How many of you line pilots are satisfied with the ground school you have received on CBs and Wx radar? Most training I have seen is pathetic. Airlines seem to assume their pilots have received the training by the time they are Air Transport Pilot rated.

GB

SEA Cb
 

Just back from a tour of Oz and SEA--a question on this topic

South of, and inbound to, KL in front of us was a large pile of thoroughly bad looking storms. At FL 470, HUD says we will not top them, radar tilted down 2-3 degrees confirms LOTS of rain, captain says the radar at zero tilt doesn't paint anything, so we clear:rolleyes: I ask to deviate right and its granted, but just in the nick of time. Some clouds are still growing and we cleared on building Cu by a little.

Any advice of dealing with weather in that area? Different than my experience in the Midwest and Southeast US, I would guess.

GF

The updraughts in a Cb can lift lumps of ice the size of your fist high into the stratosphere so go figure.

Never ever intentionally fly into one. Remember that embedded Cbs can be embedded in cloud........or embedded in darkness. A friend of mine took a short cut in a 777 based on what the wx radar said and even with the throttles at idle and the spoilers fully deployed, he was climbing :ooh:

GF,

Remember that your radar can't paint the tops of the clouds; when you look to see what's there, you're not seeing what's there.

Someone I know destroyed both engines on a weather research airplane just a few years ago He caught the tip of something around 35,000 or so, in the dark. He was painting down and contrasting it against the terrain. A zero tilt check showed nothing ahead. he intended to overfly the cell for some tops measurements with the onboard sensors and probes, then drop down and start working around some of the upcoming towers feeding into it.

His last words, reported to me, were "let's see what this one's got." He wasn't killed, though his employer certainly thought about it. What was in there was very large hail, and it hammered the airplane severely...breaking fan blades, crushing spinners, crushing nacelle leading edges and wing leading edges, shattering the radome, etc. Overflying the cell can be a risky thing to do, especially one that tall. What's visible in the cell is only part of the picture.

A very general rule of overflight is that you should stay at least 1,000 above the cell tops for every ten knots of wind at your altitude. If you have 70 knots of wind, you need an additional 7,000 above that cell. Any cell above 30-35,000' should be considered severe, regardless of the location, and treated accordingly. Don't think simply because it's found in the ITCZ or a subtropical location, that it lacks energy; that could be a fatal mistake.

I've been monitoring weather closely in the middle east, just lately, and not long ago saw some severe weather putting out 1" hail (in, of all locations, a place called "hail."). You might be surprised what pops up when you least expect it.

SNS3:

Thanks a lot. I am new at the "high altitude" flight (above 410), all my previous experience in the Thirties (C-5, sometimes low 30s) and 450 and above seems to be a "silver bullet" to some. "We'll top it, no worries", but I agree that if you are not topping by a lot, DON'T and a whole bunch might not work. Glad to hear the 1,000 ft/10 knots of wind verified, I have heard that before.

Your experience does NOT, I take it, relieve ITCZ and tropical storms from being a concern, then?

GF

Thanks for your great stuff, BTW

Basic radar usage videos are a great help on learning to avoid severe weather. Learning how to see the big picture, long range radar, and as you get closer use the shorter range to avoid the close stuff, using the tilt properly and gain control out of the auto mode should keep you safe. I have managed to get through a lot of really bad weather without any problems with what those videos teach. After 23,000 hours with no incidents flying the US and especially MIA and down south in the summer time feel common sense and radar knowledge should keep you safe. One time leaving Managua, Nicaragua I lost all radar when it started smoking in the cockpit. Turned it off but knew coming in there were thunderstorms on my route. I deviated off course as I did landing 2 hrs before but was in the clouds so did not know how things had changed and of course ATC had no radar. Another one of our AC was coming north from Costa Rica so I asked him to scan my airway and see if the deviation was adequate. He confirmed it was with his AC radar and all was well until Grand Cayman where the wall of cells extended all the way to mexico from cental Cuba. I rerouted over the eastern part of Cuba and was able to land at MIA visually avoiding cells. Guess that was my most marginal radar encounter. If used properly airborne radar should make it a safe flight.

Thanks for reminding me of something I read in my company FM. There is a way to estimate the tops of a storm painted on the radar screen. Granted this is to determine the relative severity of the storm in question, not to be used to attempt an overflight in IMC.

First you must find the radar top. Start by scanning the parallel beam position. Once you get a good echo, continue to increase the tilt until the echo disappears. Note the tilt. Now we can find the actual radar top. The formula is simple and is as follows:

distance to echo x 100 x degrees of tilt change from parallel beam = radar top

So for example we have an echo 40 miles out. We increase the tilt until the echo falls off the screen and we needed 4 degrees of tilt to do so.

40 x 100 x 4 = 16,000. Therefore the radar top is 16,000 feet above the current flight level. To find an approximate actual top we multiply the 16,000 in this example by 120% and the actual top comes out to 19,200 ft above the current flight level.

Remember the actual top is always 120% of the radar top that we found using the said formula.

Hope someone else found this little tid bit as interesting as I did. It's good to know!

tilt the radar to get ground return at 80miles. Anything that still paints inside this you will most likely go through.

this thread is ultra enlightening---I'm not as brave as Guppy though--I'll go way around or land--though I'm glad some brave souls do the research tho----:D

PA

In order to know the tilt, you need to determine true zero first. The tilt in degrees as indicated on your display or on the tilt knob isn't indicating the true tilt. Also, one needs to know the size of the dish and width of the beam.

Even at that, where the return runs out isn't necessarily the top of the cloud or the storm. Where the cloud ends may be much higher, as may turbulence. The returns will change as the cloud glaciates (turns to ice) and starts to decay.

A good rule of thumb, rather than attempting to climb over, is just to go around. When trying to plan a path across a cell by figuring the tops, you may be surprised if the cell continues to climb. It can continue to build, or additional cells build much faster than you can climb...and it may well be attenuating things building behind it. Best to go around.

I did not say where the tilt runs out is the top of the storm, hence the formula to find the radar top and then the approximate actual top. This is from our company (legacy US carrier... you guess which) 757/767 flight manual. I don't think it's lying to me.

Kind regards. :ok:

Nobody said you're lying, or the manual is lying. It's just that it only tells part of the story.

You're still far best to go around.