Thunderstorm Flying Altitude

[sky37d]

My big trip is coming up, AZO to PWA, in my little Skymaster. A bunch of us are having our annual fly-in there. The forecast up and down the line is T-Storms. I normally fly at 6-8 K, but is there a better altitude to fly at (no FL stuff) ? Am I better off up at 12K than down at 6K?

Oh, no storm scope. I do have radar, and know how to use it.
Also, when would you turn off the Autopilot??

Thanks

 

[HAZ-MAT]

From my experience, and yea, i've seen a few.. Is 3,000 feet, or the MEA. All the flying i've done in and around thunderstorm lines, have been in the south where the elevation is 2-300 feet... so if this is in the rockies... sorry cant help you there. If you are in radar contact, sometimes approach/center will help you out too, since you have radar. If i see red or purple, i ask approach what level of intensity they're seeing.. if its purple and they're saying level 3 or 4, then it'll be a bumpy ride, but no hail... 5 and up... good luck bro.

 

[CDVdriver]

Ohoh...

According to the powers that be (article in Flying) the lower the better...low and mid teens are the most dangerous altitudes 'cause of the strongest up & down drafts.
Not that I would knowingly fly through a thunderstorm.....
I'm too scared.
Think I have on a couple of occasions, hail heavy rain, downdrafts severe turbulence..students going unusual attides on you for real.
God bless single engine airplanes with no equipment in IMC.

 

[CaSyndrm]

I like to be 3 mistakes above the ground.

 

[Vector4fun]

My limited experience with basic (GA) airborne radar says you'd generally be better off below the bases of the clouds. The radar in the MU-2 I used to fly 20 yrs ago was useful, but could get you into big trouble if you trusted it too much, and poking around through mid-level clouds, mostly IMC, while watching the radar only was trusting it too much!

(Reminds me of a story for Mar's thread)

Stay low enough you can compare what the radar shows with what your eyes tell you. Navigate visually around the rain shafts and meaner-greener looking clouds. When in doubt, trust the eyes more than a faint return. Never be reluctant to land some new place and think about it from the pilot's lounge. I figured I always thought clearer on the ground with a full cup of coffee and an empty bladder, than the other way around. You also meet some very nice folks at those odd airports.

Regarding ATC help, most Approach Controls have decent WX radar capability, but don't trust Center WX radar too much for tactical help close to the storms. It just isn't that precise. Center radar is more of a large area, strategic view. Depending on the Center, they may have some other, more accurate tools available, but I can't tell you which ones have which.

The only way I'd fly around convective activity in a piston airplane is DAY VMC only.

 

[Hugh Jorgan]

T-storms? I've found 0 AGL works great when the T-storms start popping up.

 

[falcondriver]

Hugh has the right idea.
FD

 

[freightdoggie]

Unfortunately O AGL doesnt pay the bills,
deviation however, satisifies both parites....

My girlfriend and the electric company

 

[172driver]

If i see red or purple, i ask approach what level of intensity they're seeing.. if its purple and they're saying level 3 or 4, then it'll be a bumpy ride, but no hail... 5 and up... good luck bro.

Oh yeah...a level 3 or 4 is child's play. A little bumpy in a GA aircraft but perfectly safe.

 

[IP076]

Altitude: If you can't make it over the top, go low. Like haz-mat said, 3,000 or so.

Autopilot: I usually turn the thing off before it gets too bumpy. Leaving the AP on could definately over stress the airplane. If you're looking for something specific, look at the IAS and the movement of the trim wheel. If you autopilot is constantly retrimming the airplane, your in an area with significant vertical movement of air. Remember, set the power to a setting that would maintain an airspeed somewhere below Va and maintain ATTITUDE, do not chase after Altitude or Airspeed, or you could have just left the autopilot on..... Request a block altitude from center, they'll be able to give it to you since no one else will fly thru there (unless its night, and then you got the dogs to deal with )

You know what....two sections in the AIM cover this, you should read those too, 7-1-28 and 7-1-29!

 

[falcondriver]

Just remember sky37d, you are the one that gets killed if you push it too far. Stay in your comfort level and survive. Take it from someone who has pushed it too far a time or two and scared the s$hit out of myself. Cherry Air Style.
FD

 

[Checks]

If you can get on top that is the best because you will see those monsters poking thru the tops. If not then I agree that down low is better but the best thing is to know how to use the tilt feature on your radar system.

 

[Dustin H]

I use to fly through squall lines every night when I flew cargo in a Barron. I'd fly though level 5 and 6 with out any problems so it can be done with a certain level of safety.

Stay as low as you can, but try to stay in radar contact and leave enough altitude between you and the ground, I'd say no less than 3000 AGL

If it gets really bumpy, disconnect the autopilot, slow the a/c down to Va and ask for a 1000' block altitude. They will give you the block because most pilots will not be flying in these conditions. Don't be afraid to use this block either. I've ridden 4000 FPM updrafts/downdrafts before, just remember to add power on the strong downdrafts. Most of the time they will just be momentary only lasting a few seconds.
If ATC reports heavy T storm activity ahead, do what I've just written before it gets bumpy. You don't want to penetrate this stuff at your cruise speed.

Sorry if I've just repeated anyones advice above.

 

[Moonfly201]

A friends father who retired Eastern Airlines in 1975 spent much of his 30,000 hours plus career flying around the East in DC-3's. These were the days before stormscopes and weather radar existed.

Regarding light, non-turboed aircraft, his advice was go low and stay visual. And if you can't stay visual, retreat and land somewhere.

I have followed his advice and never entered a T-storm. The couple of occasions I tried to stay in the 10K to 15K range and circumnavigate a cluster while IFR, I wished I had gone low.

 

[dmspilot00]

Where can I find information on how Thunderstorms are rated and what the different levels mean?

 

[Moonfly201]

This link explains how the latest Doppler radar works. The levels of precipitation that ATC uses to rate cells simply refer to the amount of reflectivity displayed on their equipment. The higher the number, the more reflective (denser) the cell, from one to six.

Be careful, because a level 4 cell in Florida is a lot less dangerous than a level 4 cell in Kansas.

http://www.crh.noaa.gov/fsd/soo/doppler/doppler.htm

 

[sky37d]

Thanks to all
I never thought about lower being better. Obviously, higher than anything is great, but a normally aspirated airplane is only going to go so high.

I do know how to use the tilt feature, and the only time I have seen really heavy stuff, we deviated around it. So was everyone else that day.

The advise to stay on the ground is sound, but not always possible. Comfort factor is a big thing, and I have lots of things yet to do, so no hari kari on this trip. I normally disconnect the A/P as soon as it gets choppy, for the reasons mentioned, but also most will disconnect on their own at some point, and I don't want that to happen when it decides, rather when I decide.

What else? Great info here as always.

 

[Flywrite]

I use to fly through squall lines every night when I flew cargo in a Barron. I'd fly though level 5 and 6 with out any problems so it can be done with a certain level of safety.

Flying through level 5 and 6 thunderstorms can not be done safely, period. You may think you are safe the first 100 times, but 101 might kill you. On the other hand, number 1 might be the one that gets you.

When a guy with less experience starts asking the best way to penetrate TBs I dont think it's wise to give him the impression that it can be done safely.

Go around it or wait it out.

 

[falcondriver]

Well put flywrite.
FD

 

[sky37d]

I agree.

Also, comfort level thingie.
When I flight plan, for longish trips, I plan for 3 hours then on the ground. Using AirNav, for lowest fuel prices, they suggested UBX, $2.00/gal. On examination, it only has an ndb approach. I just completed my IPC, and BFR, and my ndb approach was picure perfect. Not only that, it felt good. However, if I'm off by myself, as I am this trip (usually my wife flies with me), I like ATC towers, and better approaches, so I'm planning for TBN. Little longer first leg, shorter second leg, fuel is $2.20. small price to pay for increased comfort level. When we would go east, AZO to SFM, we would stop at SYR. There is a place not far, lower fuel, but SYR has a tower. comfort level.
Thanks

Oh, go around. My first long trip was AZO to MIA, then over to MYAT. On the way back, there was the usual string of storms from OK to WVA, so we did an end around. Flew to Richmond, checked radar and weather, then over to IPT, then home to AZO. Ran into a bad stretch, big bright returns on my green radar display, and we went around those. Way around. I read that 20 miles is sort of a minimum clearance, and I like that.

 

[Dustin H]

Flying through level 5 and 6 thunderstorms can not be done safely, period. You may think you are safe the first 100 times, but 101 might kill you. On the other hand, number 1 might be the one that gets you.

I use to think the exact same way until I had a few seasons of doing it myself. Most pilots go around it so they don't have any experience with it. I had no choice because I was flying night IFR without radar, and if you've ever flown for a shoe string cargo company, you know what kind of pressure you are under to make the flight. If it's just yourself on board, fine. If you have passengers, go around or wait it out.

I agree 100% going around or waiting it out is the better alternative. But if someone is going to do it, I'd rather have them armed with the basics.

 

[enigma]

If you can get on top that is the best because you will see those monsters poking thru the tops. If not then I agree that down low is better but the best thing is to know how to use the tilt feature on your radar system.

Unless you can obtain a SR71/U2/Mig29/space shuttle, you will not get on top. I have a significant amount of time in a Lear certified to FL510 and I can tell you that thunderheads can top any altitude I could reach. I once tried to top one on the old J86 between LEV and SRQ (over the Gulf of Mexico) by going to FL450, I topped the visible cloud by a couple of thousand feet, but still came close (pucker factor level 9) to suffering an upset. Quite simply, the downdraft adjacent to the core updraft was much stronger that the old Lear could overcome. It hit hard and fast, I initially hoped that max power would suffice, after about 1/2 of a second I bailed and pitched over. That stopped the airspeed loss, but we then went into an updraft. It was an interesting ride. The boss, who never buckled up, put his belt on after that one. It is NOT a good feeling to be seven and a half miles up, sideways and falling.

If you can't reliably circumnavigate a CB, go back. The advice to go low is not advice to go under. Going low allows you to see the clouds and rainshafts so as to allow you to circumnavigate.

Good Luck, and I hope that you don't need it.

enigma

PS, the cell I attempted to overfly was the ONLY cell for fifty miles. It just happened to be on the route and I was in a hurry. Stupid, Stupid, Stupid. I could have deviated and not lost more than sixty seconds. That's what we call a "learning experience". Unfortunately, the Maddog I fly currently has a hard time getting over 330, so I now almost never get to use my knowledge. I have no choice but to deviate.

 

[Axel]

Just a matter of time

Where should we send the flowers, Dustin?

 

[prpjt]

I use to fly through squall lines every night when I flew cargo in a Barron. I'd fly though level 5 and 6 with out any problems so it can be done with a certain level of safety.

Layman's terminology: I drive drunk all the time without any problems, so it can be done with a certain level of safety"

The above quote is just so wrong.... on so many levels, it's difficult to know where to start. But here it goes.... just humor me.


Eastern Flight 66 - JFK - Reported weather: 4000 broken, 5 in HZ

Perhaps this excerpt from the NTSB report will have some meaning: ....described EAL 66's approach as normal--there was little or no turbulence. According to one of the attendants, the aircraft rolled to the left, and she heard engine power increase significantly. The aircraft then rolled upright and rocked back and forth. She was thrown forward then upright. Several seconds later she saw the cabin emergency lights illuminate and O2 masks drop from their retainers. Her next recollection was her escape from the wreckage.

This aircraft flew under a Level 5 cell at the OM....never made it to the runway. Must have not been at Va, huh?


Another example:
Delta flight 191 - DFW - Reported Weather:6000 BKN, 10 mi

At 1804 a radar specialist reported the presence of a cell at DFW and was described as (paraphrased) "reflectivity NOT equal to or greater than level 4"

At 1805 Delta 191, a Lockheed L1011 entered that cell at an altitude of about 2500'. Never made it to the runway.

Delta 191 was third to land behind a 727 and a LR25. The lear went through 2 minutes earlier, and reported after the crash that he had experienced "light to moderate turbulence"

Level 5 and 6 returns have rainfall rates of 4.5 to 7.1 inches(5) and +7.1 inches(6) per hour. These rates can flame out engines. Examples can be found courtesy of the NTSB.

As to Dustins savvy advice to ask for a 1000 foot block, it really makes me believe this guy got lucky and never penetrated the worst of it. The reason is that a bad thunderstorm will laugh at a 1000' block altitude. You can easily ride 2500' feet and not be able to do a damb thing about it. As to manipulating the power while in an actual bad cell (in a Baron) I just can't see it. I have been in a Baron in a situation I didn't want to be in, after a radar failure. Gear down, slow speed, Keeping the plane upright was purely luck.

Dustin, you got lucky - realize that.

 

[CaSyndrm]

Dustin H says
"I had no choice"


I say "Bull **CENSORED****CENSORED****CENSORED****CENSORED**"

 

[CaSyndrm]

Wow, I've never been censored before. I thought this was an adult website and am very surprised to see what happened to my last post.

Maybe there should be a thread on censorship and the website will see that most reply's will be against censorship. I think.

 

[dmspilot00]

Wow, I've never been censored before. I thought this was an adult website and am very surprised to see what happened to my last post.

It's automatic and probably something that came as part of the software we're using. Don't take it personally.

 

[Hugh Jorgan]

If it's just yourself on board, fine. If you have passengers, go around or wait it out.

So dying's okay as long as you don't have an audience?

 

[Dustin H]

Prpjt –

You are listing large turbine aircraft on final approach. A little different than a twin-engine light aircraft in the enrought portion of the flight. Airplanes crash because of crosswinds, but is that any reason not to fly when they exist. Airplanes have crashed in all situations, so listing them doesn’t prove anything. I’ll agree flying into a t-storm is just as dangerous as driving drunk if the right precautions are not taken.

CaSyndrm –

Yes, of course I had a choice, but can you remember when you had no flight time and you would do just about anything to build multi time and living paycheck to paycheck? I saw guys who refused a few flights and later got canned over something very minor, or had their schedules rearranged. After awhile I got comfortable flying through bad weather, so it didn’t bother me.

Hugh Jorgan –

I guess I didn’t make myself clear. You wouldn’t want to bring passengers into a heavy t-storm because most people don’t handle turbulence the same way we do. They can get nauseous and scared and it’s just not comfortable. Thanks for trying to understand what I was saying though.


Did any of you have a bad experience with flying in bad weather? You all seem very gun-shy on the subject. In all the bad weather I’ve ever flown in, I’ve always been able to maintain positive control of the aircraft and never felt like I was pushing the limit. Maybe I was just lucky. I think you could say the same thing about someone’s parachute always opening. They are just always lucky the chute opens.


I had a run from Memphis to Kansas City where there would always be a thick line of t-storms that I would have to go though. I’d get on the ground and see the radar had a thick line of red about two to three states long. Going through that stuff really wasn’t that bad, at least not with my experience. I will think twice about posting advice based on my experience though. You guys are brutal.

 

[Hugh Jorgan]

Did any of you have a bad experience with flying in bad weather?
Yes.

You all seem very gun-shy on the subject.
We are.

In all the bad weather I’ve ever flown in, I’ve always been able to maintain positive control of the aircraft and never felt like I was pushing the limit.

If only stupidity hurt, you might have then felt it.

Maybe I was just lucky.

You were.

I think you could say the same thing about someone’s parachute always opening. They are just always lucky the chute opens.
With that reasoning, we are always just lucky when we get three down and locked.



there would always be a thick line of t-storms that I would have to go though.

Why would you "have" to go through it?

Going through that stuff really wasn’t that bad, at least not with my experience.

Well, all that experience must make you immune to basic physics.

I will think twice about posting advice based on my experience though. You guys are brutal.

If only you would think twice about flying through T-storms.