How reliable will ATC vector you around thunderstorms?

TimRF79

TimRF79

Pre-takeoff checklist
Joined
Dec 10, 2017
Messages
352
Location
Houston, TX
Display Name
Display name:
Tim
This may seem like a silly question, i am IR rated and current, but not much IR time.
When on an IFR flight, will ATC vector you around severe weather?
Or will they vector to "thread the needle"?

What if there is a 100 mile wide band? Do they advise you to turnaround/land?
 
That's an interesting question, but no matter the answers provided here, for my safety, I would always assume they will not vector me around any storms in any way and that it is 100% my responsibility.
 
You'll hear things like "there is an area of moderate to heavy precipitation at your 12 o'clock, 25 miles, let us know if you need to divert around it" but I don't think you'll ever get "turn left heading 290, vectors between two areas of extreme precipitation."
 
I have one experience, where it was a wide band but I was able to parallel, and that was the vector they gave me. With NEXRAD being up NN minutes delayed, ATC isn't going to give you a vector to thread the needle. You can choose to do so....but that's on you.
 
There's a few things important to realize about ATC and weather displays they have, and their capabilities/abilities to do anything.

YOU are responsible for weather avoidance. They will provide you with assistance if you ask, and will advise you of weather they see, but it's up to you to figure out what you want to do.
They do not know the capabilities of your aircraft.
They do not know what you are seeing, or your actual flight conditions. Example - ATC will occasionally warn you of an area of heavy precipitation, when you can see out your window that it's not a big deal and there's no need for them to vector you around it.
Conversely, they can't see turbulence (or even clouds). So you need to tell them if you need to be vectored around a buildup.
If you're at a low altitude, it's possible that what looks really bad to them on the radar is all above you, and you can easily dodge rain shafts visually. Not a big deal, but it may look very ominous to them.
If you're at a high altitude, it's possible that what looks really bad to them on the radar is all below you, and isn't a factor at all (granted, this is usually up in the FLs, which I assume by your question that you're not flying in, though it's possible).
 
You are responsible. If you’re headed right for a cell, they’ll usually advise you to deviate. Also just because another aircraft went through it, doesn’t mean you should.
 
I just flew about 1,200 nm from Key West to Massachusetts. Every time I was about to call up ATC about deviations around big cells, the controller would call me with a route change. It happened at least 5 or 6 times and put me clear of most of the weather without me having to ask. They did a great job IMO.
 
jordane93 said:
You are responsible. If you’re headed right for a cell, they’ll usually advise you to deviate. Also just because another aircraft went through it, doesn’t mean you should.
Click to expand...

Yup, sometimes they can't see what you are seeing. Ask early and often.
 
My thought is, and maybe i am wrong, if I am in the clouds in IMC, I will not see a "bad cell" ahead of me in the clouds (embedded t-storm).
But do appreciate the feedback, i think i need to go to an atc-course so i know what they see
 
TimRF79 said:
My thought is, and maybe i am wrong, if I am in the clouds in IMC, I will not see a "bad cell" ahead of me in the clouds (embedded t-storm).
But do appreciate the feedback, i think i need to go to an atc-course so i know what they see
Click to expand...

ATC doesn't know if you are IMC or not, unless you tell them.
 
TimRF79 said:
This may seem like a silly question, i am IR rated and current, but not much IR time.
When on an IFR flight, will ATC vector you around severe weather?
Or will they vector to "thread the needle"?

What if there is a 100 mile wide band? Do they advise you to turnaround/land?
Click to expand...
Keep in mind that ATC does not see what you see out the window, and as PIC you are solely responsible for safe flight

I've had ATC tell me there is a line of precip ahead or some other updates based on what they have but I wouldn't trust them to do anything beyond potentially give an advisory

A few personal examples

(1) I saw my destination (not the airport, but the mountain valley it is located in) about 25 miles away but it looked "ominous" with lots of weather around it (July storms in the Sierra Nevada mountains out here on the way to Kern). I *probably* could have made it in but ATC was very "firm" on their "not advisable" to proceed flight further. I was IFR.. in and out of layers.. so figured why be a hero and I spent the night in Van Nuys

(2) coming back once, similar area, the view looked downright scary to the right and ahead.. at 14K this stuff was towering over me. ATC said they saw the precip but were unable to vector me away from it for another 15-20 miles.. again, IFR, in and out of IMC, so my only option was to declare or proceed. Pressed ahead, they finally gave me a vector to the left away from it.. another 1-2 minutes though and I would have declared

(3) it has also happened where they're warning me of heavy precip but I'm well above it in clear skies with VFR conditions ahead.. so I thanked them for the update and continued on

The TLDR is.. don't assume anything

Salty said:
I would always assume they will not vector me around any storms in any way and that it is 100% my responsibility
Click to expand...
exactly

Reminds me of this.. some good examples of this. Notice Delta asks for a vector from ATC.. not the other way around. But the real good stuff starts with Aer Lingus
 
TimRF79 said:
My thought is, and maybe i am wrong, if I am in the clouds in IMC, I will not see a "bad cell" ahead of me in the clouds (embedded t-storm).
But do appreciate the feedback, i think i need to go to an atc-course so i know what they see
Click to expand...

Your responsibility to avoid weather doesn't stop just because you can't see anything out the window. ATC will do what they can to help keep you pointed in a good direction but you need to tell them what you want/need to do, not wait for them to tell you to do something.

It's a whole lot easier to avoid weather now that so many light airplanes have some sort of on board weather they can use, be it XM, ADS-B, or real time radar. Use the tools to your advantage but understand their limitations.
 
TimRF79 said:
My thought is, and maybe i am wrong, if I am in the clouds in IMC, I will not see a "bad cell" ahead of me in the clouds (embedded t-storm).
But do appreciate the feedback, i think i need to go to an atc-course so i know what they see
Click to expand...

There are a lot more people here with a lot more experience than me, but embedded t storms are bad news in my opinion. If I can't see the t-storm (ie if I'm in a cloud), then I don't want to be anywhere near it, regardless of whether ATC or I can see it on the weather screen. I don't have radar.

So embedded t-storms are generally a no go for me.
 
PaulS said:
There are a lot more people here with a lot more experience than me, but embedded t storms are bad news in my opinion. If I can't see the t-storm (ie if I'm in a cloud), then I don't want to be anywhere near it, regardless of whether ATC or I can see it on the weather screen. I don't have radar.

So embedded t-storms are generally a no go for me.
Click to expand...
So, do you not fly in IMC, or do you trust ADSB weather?
 
PaulS said:
I do not fly around t-storms I can't see. ADSB weather does not count as seeing.
Click to expand...
I'm struggling to understand you. How do you know something is there if you can't see it?
 
Salty said:
I'm struggling to understand you. How do you know something is there if you can't see it?
Click to expand...

Embedded thunderstorms are usually forecast. When t-storms are embedded, it means they are part of a larger rain system, usually meaning IMC conditions in a large area, with thunderstorms inside of that IMC area. I am fine flying in IMC, I am fine flying near T-storms, within reason, if I can visually see them. When the t-storms are embedded in a larger IMC weather system, that usually means you can't see them visually. I have adsb in the airplanes I fly, but the radar images can be up to 20 minutes old, which means the T-storm can be many miles away from where they are depicted, or much bigger than depicted on the onboard adsb weather. So if I know there are thunderstorms, I will not get anywhere near them if I can't see them. I don't have on board, real time radar.

How do I know there are there embedded t-storms there ? Well, if I'm in IMC, I don't, at least not precisely enough to try to avoid them. I also have my pre flight planning, adsb and ATC. Like I said, if embedded t storms are forecast where and when I want to fly, and I can't circumvent them by an appropriate margin, probably at least 30 miles. I stay on the ground.
 
PaulS said:
Embedded thunderstorms are usually forecast. When t-storms are embedded, it means they are part of a larger rain system, usually meaning IMC conditions in a large area, with thunderstorms inside of that IMC area. I am fine flying in IMC, I am fine flying near T-storms, within reason, if I can visually see them. When the t-storms are embedded in a larger IMC weather system, that usually means you can't see them visually. I have adsb in the airplanes I fly, but the radar images can be up to 20 minutes old, which means the T-storm can be many miles away from where they are depicted, or much bigger than depicted on the onboard adsb weather. So if I know there are thunderstorms, I will not get anywhere near them if I can't see them. I don't have on board, real time radar.

How do I know there are there embedded t-storms there ? Well, if I'm in IMC, I don't, at least not precisely enough to try to avoid them. I also have my pre flight planning, adsb and ATC. Like I said, if embedded t storms are forecast where and when I want to fly, and I can't circumvent them by an appropriate margin, probably at least 30 miles. I stay on the ground.
Click to expand...
Thanks. That helps. I guess where I misunderstood you is that when you say "I don't consider adsb seeing them" you only mean that in a negative way, not a positive one. In other words, if it's not forecast, but you see it on adsb, you DO consider that seeing them, but if you don't see them on adsb, but they were forecast, you also consider that seeing them.
 
Salty said:
Thanks. That helps. I guess where I misunderstood you is that when you say "I don't consider adsb seeing them" you only mean that in a negative way, not a positive one. In other words, if it's not forecast, but you see it on adsb, you DO consider that seeing them, but if you don't see them on adsb, but they were forecast, you also consider that seeing them.
Click to expand...

Pretty much, if I see it predicted in a forecast, and I see a front barreling toward where I want to be, and the conditions are ripe for a t-storm to blow up, all near flight time, then I probably would scrub. It's not all black and white on the forecast end. It is black and white for me for established or growing storms. If I can't see the t-storm visually I want nothing to do with it.

I actually saw a t-storm form in front of me flying in NC on my trip to Sun and fun. There was a nasty t-storm to right, about 35 miles away, there was a smaller nasty looking storm on my left, both depicted on adsb for a while, with a big space between them, about 45 miles wide. Airliners were zipping through at 500 mph, of course I was only going about 200 mph. I was almost through it and clear, then I noticed I couldn't see as far through as I could a few minutes before, then I saw precip falling about 10 miles in front of me. ADSB was still showing clear. So I called ATC and asked for a left deviation, as by this point I was clear on the left, that storm was behind me. About 3 or 4 minutes after I got the deviation, adsb started showing the precip next to me, it went from nothing to green, then yellow, then a blob of red in the middle, probably around 10 miles in diameter. That's why I want to be able to see them.

You're in Florida, so you get more of this weather, than me in the northeast, Scott D has a good book out that talks about how these storms form and how to avoid them. It's real important to remember that while adsb is great, it's dangerous to use it to pick your way around t-storms.
 
They try. Most modern equipment they get a very poor picture of weather, which is better than years ago when they got none.

It’s really up to you.
 
Have not read all replies, so forgive me please...
In recent years ATC radar has come a long way for weather avoidance. I’ve actually had TRACON thread the needle between cells. Very impressive.
That said, several years ago they had very little capability for weather avoidance.

On a side note, they will often change your arrival or departure depending on the weather.
 
Daleandee said:
Here is a video showing how sometimes what they can see may serve you better than what you can see:

Click to expand...

Absolutely, a guy I admired as a by the rules pilot, flew into a t-storm resulting in an in air break up resulting in his and his wife's death. ATC was essentially begging him not to continue before the crash. This was before on board weather.

The video you posted is a good example of the danger of using adsb to steer around storms.
 
Daleandee said:
Here is a video showing how sometimes what they can see may serve you better than what you can see:
Click to expand...

That's a great video. Hadn't seen that one yet. Good reminder (for me at least) as we move into the time of year here in the DC area where we an increaseing number of tstorms.
 
TimRF79 said:
This may seem like a silly question, i am IR rated and current, but not much IR time.
When on an IFR flight, will ATC vector you around severe weather?
Or will they vector to "thread the needle"?

What if there is a 100 mile wide band? Do they advise you to turnaround/land?
Click to expand...


Yes to all the above. I’ve done all of that on approach countless times. But, that was 25 years ago. With the technology we have in the cockpit today, I don’t see much of a need in vectors around weather. ATC has an advantage in refresh rate vs FIS-B / NEXRAD. Pretty much instantaneous for analog (ASR8) and about 30 secs for digital (ASR11). Their depiction is pretty poor vs in the cockpit color returns though.
18FFF9AC-4C3A-4823-91EB-E8B6D87F43C4.jpeg
Old friend of mine was working ATL approach during some of this.

 
Highly unlikely ATC knows anything about thunderstorm avoidance and/or detour distance. They think as long as you don't go through a weather return on their radar you're good to go. I would not accept that. Threading is for sewing. Instead, I would tell them the minimum distance I can accept for detouring around weather returns.
 
TimRF79 said:
This may seem like a silly question, i am IR rated and current, but not much IR time.
When on an IFR flight, will ATC vector you around severe weather?
Or will they vector to "thread the needle"?

What if there is a 100 mile wide band? Do they advise you to turnaround/land?
Click to expand...
ATC wants to help, and they've been great with me, but don't bet your life on it if you're in IMC with embedded TCU or TS.

Like with everything in aviation, safety comes with multiple layers: I use SiriusXM radar imagery (ADS-B coverage is limited in Canada) and a Stormscope and ATC advisories — if they disagree, I trust the most-conservative one — and even then, I give any activity a very wide berth, and I won't even launch IFR if the forecast includes more than widely-scattered embedded along my route (I'll accept a little more if I can fly VFR). Most of the time when there's convective activity around and I have to fly IFR, I find an altitude between layers where I can stay visual, which acts as a fourth safety layer. My single can't carry radar, but that's yet another useful safety layer for the twin jockeys.
 
flyingron said:
Note that ATC doesn't see thunderstorms. They see rainfall.

And for those who didn't catch my earlier comment: https://app.ntsb.gov/pdfgenerator/R...tID=20060501X00494&AKey=1&RType=HTML&IType=MA
Click to expand...

I believe one of their newer systems is slightly better integrated with local Doppler and does a tad more than rain reflectivity — even that the controller can see — but not widely deployed at all. Seems like it went in in places that experience lots of low level wind shear first... then I stopped looking it up.
 
On my first real cross country after getting my IFR I was nearing Detroit when a line of thunderstorms was passing through the area. The controller had me go northbound up the west side of the city while waiting for a break in the line.

We were VMC looking at the cells out the right window and saw what looked like a break ahead, but before we got there the controller asked us to turn East to get below traffic heading into Detroit.

There was a large dark cell out that window but the AddsB showed light rainfall, the Stormscope was quite in that direction, and, when I asked, the controller said he didn’t show significant activity that direction. It didn’t look good out the window but I was new to IFR so I turned east. I essentially gave up my pilot in command authority.

I slowed to maneuvering speed in case we hit turbulence and as soon as I entered the dark cloud the plane into what seemed like a 90 degree bank with violent up and down drafts. Stuff was flying all over inside the plane and I got a good demonstration of what moderate to severe turbulence was like. I didn’t think I was unable to control the plane, so it may have not been ‘severe’, but it was close.

I dropped the gear to add drag, focused on keeping the wings level, and rode it out. We were through the cell in under a minute but as soon as we popped out the area behind us lit up, there was a very loud boom, and the stormscope whited out. I’m convinced that the cell popped out a lightning strike right behind me.

I told the controller that I thought that we had been routed through a cell that had just gone active. He said he just got an indication that it was a fully blown thunder cell and asked if we wanted to declare an emergency. Everything seemed to be working fine so we continued on to our destination.

That was the day I decided to say unable the next time a controller asked me to do something that I wasn’t comfortable with. If you are VMC, never trust your, or your controllers, electronic displays over what you see out the window, and always remember that you are PIC.

Gary
 
If you don't have a weather radar on the airplane (not XM or other ground-based radar summaries) then find an altitude where you can see the storm. ATC can help, but they don't have the equipment, nor time, to be your primary means for avoiding convective activity.
 
Larry in TN said:
If you don't have a weather radar on the airplane (not XM or other ground-based radar summaries) then find an altitude where you can see the storm. ATC can help, but they don't have the equipment, nor time, to be your primary means for avoiding convective activity.
Click to expand...
Fair point, but with XM weather and a Stormscope and ATC advisories, I am willing to fly in IMC when the CB or TCU are widely scattered and I can give them a wide berth. No one of those things would be enough in itself. On that note, even weather radar by itself isn't ideal, since heavy precip doesn't correlate perfectly with storm clouds (I'd want to add at least a lightning detector).
 
Larry in TN said:
If you don't have a weather radar on the airplane (not XM or other ground-based radar summaries) then find an altitude where you can see the storm. ATC can help, but they don't have the equipment, nor time, to be your primary means for avoiding convective activity.
Click to expand...

Larry and I don’t agree about electric cars but this is nailed. If it doesn’t look right don’t fly into it. Even the onboard gadgets can break.
 
David Megginson said:
Fair point, but with XM weather and a Stormscope and ATC advisories, I am willing to fly in IMC when the CB or TCU are widely scattered and I can give them a wide berth.
Click to expand...
I've never flown with a Stormscope but that sounds reasonable to me.

I have fairly advanced onboard radar with doppler turbulence detection as well as WSI weather, via datalink, but I'll still find an altitude where I can see the storms if I can. This is particularly true when looking for a way to get to the other side of a large line of storms. The weather map via datalink can be significantly behind a fast storm's actual positions so it's more of a strategic tool when I'm still a couple hundred miles away trying to decide which direction to go.
 
Some examples of ATC digital weather echos. Some versions like the top use intensities. Analog systems never have intensity just “areas of precipitation.”
At any rate, while the areas are pretty well defined and ATC should have no problems vectoring around precip, it’s up to the pilot to determine what’s a safe distance.

C4897AF4-F16A-4CF0-92FF-C69D0CD549BC.jpeg 330CEF30-D35E-4923-ABE7-E25C4A35D044.jpeg DFB4162D-2AEA-4050-9D46-14D9CE06E3D6.jpeg
 
TimRF79 said:
This may seem like a silly question, i am IR rated and current, but not much IR time.
When on an IFR flight, will ATC vector you around severe weather?
Or will they vector to "thread the needle"?

What if there is a 100 mile wide band? Do they advise you to turnaround/land?
Click to expand...

You are the PIC, right? Tell the controller what you need. ATC will not make these decisions for you.
 
Also sometimes their echoes are wrong or delayed. They’ve told me there’s heavy to extreme precipitation in the FLs right ahead of me and it was severe CAVU
 
You must log in or register to reply here.
Back
Top