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Heights Of Thunderstorms And Flying Over Them  
User currently offlineJulianUK From United Kingdom, joined Apr 2006, 105 posts, RR: 0
Posted (8 years 4 months 18 hours ago) and read 32767 times:

As an airline pilot if you are approaching a thunderstorm on the weather radar and you can visually see it, can you actually fly over it safely or are you not meant to judge the height of it and have to turn around it whatever? I just wonder whether pilots are allowed to guestimate the height of it and go over it?

33 replies: All unread, showing first 25:
 
User currently offlineJoness0154 From United States of America, joined Nov 2005, 667 posts, RR: 0
Reply 1, posted (8 years 4 months 18 hours ago) and read 32767 times:

You can pan the weather radar up and down to find the height of the cells. You can also check visually. Although with all the rising convection I don't know if I'd want to fly on top of them, some of the cells go up to 60,000+ feet. I'd rather fly around them.


I don't have an attitude problem. You have a perception problem
User currently offlineGoldenshield From United States of America, joined Jan 2001, 6010 posts, RR: 14
Reply 2, posted (8 years 4 months 18 hours ago) and read 32767 times:

The general rule is 100 feet per 10 knots of wind, but with some storms, it doesn't leave much room, and going around is a better option.


Two all beef patties, special sauce, lettuce, cheese, pickles, onions on a sesame seed bun.
User currently offlineJulianUK From United Kingdom, joined Apr 2006, 105 posts, RR: 0
Reply 3, posted (8 years 4 months 17 hours ago) and read 32767 times:

Thanks interesting about weather radar giving you height.

Quoting Goldenshield (Reply 2):
The general rule is 100 feet per 10 knots of wind, but with some storms, it doesn't leave much room, and going around is a better option.

So excuse me trying to understand but that is wind at your level and is this 100 feet horizontal outwards but not up?


User currently offlineLawrenceMck From United Kingdom, joined Nov 2005, 311 posts, RR: 0
Reply 4, posted (8 years 4 months 17 hours ago) and read 32767 times:

Quoting Joness0154 (Reply 1):
I'd rather fly around them.

I think thats what pilot's generally do. As on several occasions I have encountered thunderstorms and the Captain always announces that we are going to fly around it, I think it's much safer.

Lawrence



Love It To Live It
User currently offlineSlamClick From United States of America, joined Nov 2003, 10062 posts, RR: 68
Reply 5, posted (8 years 4 months 17 hours ago) and read 32767 times:

Quoting Goldenshield (Reply 2):
The general rule is 100 feet per 10 knots of wind

Didn't you want another zero in that altitude? You really think it is okay to overfly a towering cu at five hundred feet above it with a fifty knot wind?

I recall that a bizjet had its radome shattered by flying into a hailshaft in clear air a couple thousand feet above a TCU a few years back.

Highest I've ever actually seen was on the Gulf coast, near Mobile - Biloxi a few years back. Must have been fifty miles of red and purple returns and tops reported at seventy two thousand feet.

(he shudders)



Happiness is not seeing another trite Ste. Maarten photo all week long.
User currently offlineRadelow From United States of America, joined Jul 2004, 426 posts, RR: 3
Reply 6, posted (8 years 4 months 16 hours ago) and read 32767 times:

I have been on airliners flying at ~35k going around cells that just stretched up into the atmosphere and didn't seem to stop...so yes, flying over is not really an option.

User currently offlineLH463 From United States of America, joined Apr 2006, 68 posts, RR: 0
Reply 7, posted (8 years 4 months 15 hours ago) and read 32759 times:

I have actually flown over some nasty stuff over Kansas/ Oklahoma, en-route DEN STL, it wasn't an individual CB, but there were embedded thunderstorms. When they are visible I've never flown over one, only around or right through. On approach to San Jose, Costa Rica about 10 years ago in an AA 727 we flew right through hell, it was the worst aviation experience I've ever had.
For the most part pilots flying IFR just ask for a weather deviation wherever they can, so that they are able to weave in and out of these things. I think the AIM also says that pilots should avoid CB's by 20nm or more to avoid it's effects, such as wind shear etc. Please correct me if I'm wrong...

Regards,
LH463



Turning final...
User currently offlineMeister808 From United States of America, joined Jan 2000, 973 posts, RR: 1
Reply 8, posted (8 years 4 months 11 hours ago) and read 32690 times:

Quoting SlamClick (Reply 5):
tops reported at seventy two thousand feet

Jesus... I know that the tropopause gets significantly higher as you go south, but that is nuts. Updraft velocities in the core there were probably upwards of 20,000 feet/minute to get that kind of height, since anything that goes up into the stratosphere is pretty much carried there by momentum.

I can't imagine what the size of the hail that was coming out the bottom of that was... updrafts like that could keep something the size of a small car suspended for a while. Of course, I'm assuming the system was sheared, so there's a little less opportunity for hail development before things get blown out the side.

-Meister



Twin Cessna 812 Victor, Minneapolis Center, we observe your operation in the immediate vicinity of extreme precipitation
User currently offlineGoldenshield From United States of America, joined Jan 2001, 6010 posts, RR: 14
Reply 9, posted (8 years 4 months 10 hours ago) and read 32672 times:

Oops. Typo there. Yes, it is 1000.

Quoting SlamClick (Reply 5):
Didn't you want another zero in that altitude?



Two all beef patties, special sauce, lettuce, cheese, pickles, onions on a sesame seed bun.
User currently offlineMikkel777 From Norway, joined Oct 2002, 370 posts, RR: 1
Reply 10, posted (8 years 4 months 10 hours ago) and read 32666 times:

Quoting Radelow (Reply 6):
I have been on airliners flying at ~35k going around cells that just stretched up into the atmosphere and didn't seem to stop...so yes, flying over is not really an option.

This is taken one or two days after emily last year, EWR-MCO et FL380. Did a lot of S-turns to avoid TCU, so yes, airliners fly around the big cells



User currently offlineOnetogo From United States of America, joined Feb 2006, 314 posts, RR: 0
Reply 11, posted (8 years 4 months 10 hours ago) and read 32643 times:

Fantastic shot Mikkel777!

User currently offlinePilotpip From United States of America, joined Sep 2003, 3150 posts, RR: 11
Reply 12, posted (8 years 4 months 7 hours ago) and read 32608 times:

Thunderstorms this time of year in the midwest regularly get over 30,000 feet. We had some today around STL that had echo tops on the radar of FL550, the summary on the WSI only goes to FL600. At that point, the only option is to fly around. If there's a line of them, that may not even be an option.

Let the diversions begin!!!



DMI
User currently offlineSlamClick From United States of America, joined Nov 2003, 10062 posts, RR: 68
Reply 13, posted (8 years 3 months 4 weeks 1 day 23 hours ago) and read 32524 times:

Quoting Meister808 (Reply 8):
Jesus... I know that the tropopause gets significantly higher as you go south, but that is nuts. Updraft velocities in the core there were probably upwards of 20,000 feet/minute to get that kind of height, since anything that goes up into the stratosphere is pretty much carried there by momentum.

Exactly. We tend to think of 'weather' as something that happens in the troposphere - the layer closest to the surface. But I think towering cu are so powerful and so 'well organized' that they kind of create their own atmosphere. You might have a 20000 foot per minute updraft carrying tons of hot, humid, unstable air and it will just punch right through the trop. The Gulf Coast and Florida thunderstorms are impressive for sure, but I prefer them, most days, to the lines you get in the midwest. There are days when there are only a couple of holes through the line from southwest Texas all the way to the great lakes. I love looking at them and that is something best done from a little distance back.

Coming up the east coast a few years ago at 370 and only about two thirds of the way up a cell near Savannah, we saw an MD-80 from another company fly past it, four thousand feet below us and only a mile or so outside the cloud wall. Right behind him it spit out a hailshaft at about our level. Maybe a hundred and twenty seconds or so difference and he would have flown right through it, and he never even knew it happened.

I could picture that MD captain smugly congratulating himself for making the bare minimum deviation for that cell while we swung twenty miles outside it. Personally I like to fly as smart as I can and save my 'luck' for when I really can't avoid using it.



Happiness is not seeing another trite Ste. Maarten photo all week long.
User currently offlineJulianuk From United Kingdom, joined Apr 2006, 105 posts, RR: 0
Reply 14, posted (8 years 3 months 4 weeks 1 day 20 hours ago) and read 32481 times:

Is there ever a time you might have to fly through something red on the weather radar? and if you did what can the passengers expect?

User currently offlineSlamClick From United States of America, joined Nov 2003, 10062 posts, RR: 68
Reply 15, posted (8 years 3 months 4 weeks 1 day 18 hours ago) and read 32437 times:

Quoting Julianuk (Reply 14):
Is there ever a time you might have to fly through something red on the weather radar?

Perhaps if you'd already violated basic safety rules and got yourself boxed-in somewhere. In all seriousness in that situation I might consider and emergency landing on an interstate highway as being an option of comparable merit to flying through a nasty thunderstorm.

Quoting Julianuk (Reply 14):
and if you did what can the passengers expect?

Well, here's one example of what they might expect:
http://www.airdisaster.com/cgi-bin/v...21980®=N6505&airline=Air+Wisconsin

Here's another:
http://www.airdisaster.com/cgi-bin/v...7®=N1335U&airline=Southern+Airways

Vertical currents (up AND down) even in a puny little CB that tops out in the mid-twenties can easily exceed the climb rate for any airliner you can think of. Rain can flame out engines and cause compressor stalls that will destroy them (Read Southern 242 above) hail can FOD-out engines, shatter windshields (1)

Turbulence is going to be 'severe' and may be 'extreme.' Now I've experienced severe turbulence which damaged my airplanes. We get broken bones and even the occasional fatality from just severe. I've never experienced 'extreme' and do not care to.

So, unless there was some extraordinary circumstance that put you in the red returns, expect to be disciplined by the airline, maybe violated by the FAA just as a minimum. Oh, and the flight attendants aren't going to like you anymore and they will remember your name forever! You'll have to get your own coffee just for starters.

(1) Also Southern 242. I have a DC-9 first officer's windshield out in my garage. It is about 1.5 inches thick, somthing like five layers of tempered, semi-tempered and acrylic and I don't remember what else. I'd bet that you could not make a hole in it big enough for you to crawl through if I gave you a hammer and an hour to bang away at it. And the hail blew it in!



Happiness is not seeing another trite Ste. Maarten photo all week long.
User currently offlineJulianUK From United Kingdom, joined Apr 2006, 105 posts, RR: 0
Reply 16, posted (8 years 3 months 4 weeks 1 day 18 hours ago) and read 32422 times:

Very impressive thanks for the answers - I have been on flights where the pilots says "erm things are going to get bumpy for a while so we will have to strap you in" - if they are not going near thunderstorms what else is causing it and how do they know....

User currently offlineSlamClick From United States of America, joined Nov 2003, 10062 posts, RR: 68
Reply 17, posted (8 years 3 months 4 weeks 1 day 14 hours ago) and read 32366 times:

Quoting JulianUK (Reply 16):
what else is causing it and how do they know....

Thunderstorms form in 'unstable' atmospheric conditions. That is, when hot humid air is lifted, it tends to accelerate upward. So if conditions are favorable for the development of thunderstorms, then the air is just generally bumpy. So you don't have to fly very near them to get at least a taste of this. Just about anywhere over the Florida peninsula on a summer day should do.



Happiness is not seeing another trite Ste. Maarten photo all week long.
User currently offlineMir From United States of America, joined Jan 2004, 21561 posts, RR: 55
Reply 18, posted (8 years 3 months 4 weeks 1 day 9 hours ago) and read 32321 times:

Quoting JulianUK (Reply 16):
if they are not going near thunderstorms what else is causing it and how do they know....

In addition to what SlamClick said, there are weather reports and pilot reports that pilots get prior to flight. You could also ask ATC - they will occasionally query pilots as to how smooth the air is where they are, and thus build a good picture for the planes that are following, telling them where to expect turbulence, and how to avoid it if possible.

-Mir



7 billion, one nation, imagination...it's a beautiful day
User currently offlineJulianUK From United Kingdom, joined Apr 2006, 105 posts, RR: 0
Reply 19, posted (8 years 3 months 4 weeks 18 hours ago) and read 32231 times:

I have seen ACARS reports with turbulence reports on them, is this automatically done by in flight systems measuring turbulence or does the pilots have to put in what the turbulence is they perceive?

User currently offlinePelican From Germany, joined Apr 2004, 2531 posts, RR: 8
Reply 20, posted (8 years 3 months 4 weeks 17 hours ago) and read 32223 times:

On most occassions we flew right above them.

Signed,
ex-Blackbird pilot  Wink





pelican


User currently offlineWaterpolodan From United States of America, joined Feb 2005, 1649 posts, RR: 5
Reply 21, posted (8 years 3 months 4 weeks 16 hours ago) and read 32213 times:

I don't know much about cloud formation, but are there any clouds that top out at 85,000+ Ft, which the blackbird is capable of? Also, I'd imagine anyone looking to get a first hand account of severe and probably extreme turbulence should go talk with the crews of the P-3's that fly into the hurricanes each year... I've seen footage as they fly around inside the eye, but I've always wondered just how rough it can get when they fly through the eye wall. Those planes are also relatively old and slow, they must have some extraordinary matinence crews to repair them after the beatings I assume they take.

User currently offlineFr8tdog From United States of America, joined Feb 2000, 120 posts, RR: 0
Reply 22, posted (8 years 3 months 3 weeks 6 days 18 hours ago) and read 32119 times:

Thunderstorms are nothing that you want to play with. If you can avoid them, do it. A buddy of mine who was flying a F-16 in the midwest one day encountered a line of thunderstorms blocking his route of flight, thought that he could out climb and go over... Much to his surprise the line out climbed him by the time he reached Fl 500.

Avoidance or penetration depends on a number of factors,

1. what phase of flight are you in?
2. what is your experience?
3. what does the radar signature look like?
4. what is the surrounding weather doing?
5. What is the speed and movement?
6. What are other aircraft reporting and doing?

#1- Altitude is a large factor on what you can expect with ride conditions, aircraft performance and type of precip.

Downdrafts are the strongest near the base of the storm. The greatest shearing activity is near the middle of the storm and widens vertically and horizontally as the storm grows in size. near the top at the base of the outflow is where the updrafts reach their greatest velocities.

Turbulence is a change in velocity and or direction in the motion of parcels of air. (the more radical the change is, over a given distance and/or altitude is an indicator of progressively stronger turbulence)

One factor of aircraft performance is ISA deviation. I have had it where running parallel to a front on the warm side and had a steady decrease of IAS due to rapidly rising ISA, only option is to go down in order to maintain performance on the aircraft.

#2. Experience- comes from the collaboration of knowledge and hands on participation. (A fighter pilot does not become a fighter pilot on reading alone.)

#3. Thunderstorms come in a multitude of shapes and sizes, is it long and narrow, round, oblong, or does it have multifaceted sides. How close are the contours on the radar? are they symmetrical? These are just some of the questions you are trying to answer while thinking what your plan of action is going to be.

#4. speed and movement has effects on how big and aggressive a thunderstorm will be.

#5. This is part of situational awareness. What is going on in the environment around you............. this will help you in determining what your actions are going to be.

My role as an airline Capt. is #1 operate as safely as possible.
Tied with #1 is to try and give the best ride to the passengers as possible.
(they pay my wage  Wink)

Fr8tdog


User currently offlineSpudsmac From United States of America, joined Feb 2008, 298 posts, RR: 0
Reply 23, posted (5 years 3 weeks 2 days 5 hours ago) and read 30789 times:



Quoting Goldenshield (Reply 2):
The general rule is 100 feet per 10 knots of wind, but with some storms, it doesn't leave much room, and going around is a better option.

I know it is really 1000ft/10kt of wind, but I started working on my CFI and as I'm teaching this, I start to question the reasoning behind it.

In AC00-24 section 2.e, it discusses overflight of a cell, but I still don't understand the relationship between the wind at the top and turbulence.


User currently offlineGLEN From Switzerland, joined Jun 2005, 224 posts, RR: 2
Reply 24, posted (5 years 3 weeks 2 days 5 hours ago) and read 30774 times:



Quoting Spudsmac (Reply 23):
I still don't understand the relationship between the wind at the top and turbulence.

A CB acts like an obstacle in the normal flow of the wind - thus generating turbulence like e.g. mountains. The higher the windspeed the bigger the turbulence caused by the cell.

However it's not wise to overfly an active cell to close, even with no or few wind. If the CB is still building up, its top is continuously rising and you could get trapped when flying over it.



"The horizon of many people is a circle with zero radius which they call their point of view." - Albert Einstein
25 Lexy : My wife and I flew from BNA to MDW back in May and we passed through a line of very severe thunderstorms over northern Indiana. They had produced som
26 Ngr : I've experienced some really bad weather twice as a passenger. When I was younger (probably 12 or so) I recall flying in an MD-88 from ATL to CAE, and
27 HodyOaten : That's not correct; barrier effects play only a very small part and strictly speaking would only occur around the fringes of the cumulonimbus tower.
28 Post contains links JoseKMLB : http://flightaware.com/live/flight/DAL2021 This is the normal path from ATL-MLB. Early today we had some strong storms and they flew around it. http:/
29 Spudsmac : Thank you!
30 ThirtyEcho : One of the surprises from the manned spacecraft program, and other very high altitude research, was that lightning not only strikes down and sideways
31 WILCO737 : That's why we should circumnavigate the CB and not overfly it. Most of the times you cannot really fly above it anyway. Don't get too close to a CB,
32 Murchmo : I have a different story...maybe this is rare so someone chime in if they've had similar experience. Coming back from a trip to DeltaConnection Academ
33 WILCO737 : I know what you are talknig about. That is incredible. It looks great. It is a great experience. The cloud can be seen completly during the lightning
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