Author Topic: Controllers don't have a larger picture of weather?  (Read 8736 times)

Offline KSYR-pjr

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Controllers don't have a larger picture of weather?
« on: April 03, 2006, 03:42:15 PM »
I am listening to the KBUF feed (Buffalo, NY) right now and there is a Southwest Airlines jet approaching the airport from, coincidentally, the southwest.  The pilot asked about the weather and was told by ATC that the line is right over the airport and moving east.

The pilot replied that he only has one shot at landing and does not have enough fuel to hold, so his alternate would be Cleveland (to the west) if the weather doesn't allow him to land.

The controller gave him the assurance that the line is over the airport now and moving east.  

However, I am looking at the Intellicast radar mosaic for the Northeast and there is a second line, just as intense, that is developing behind the first line by about 30 miles.  

The point of my post is to question why is it that tower controllers apparently don't have access to a much bigger picture of the weather than that on their scope?  

Had the controller seen the second line forming, he would have advised the SWA pilot that the field would have been overtaken a second time by strong storms.  This is not the first time I have heard of t-storm avoidance strategies on the frequency that have not taken in the whole picture (for example, a pilot wanting vectors to the north to attempt an end-around a line, but unaware that the line to the north extends for 150 miles).

NOTE:  As I typed this, the SWA pilot opted to divert to Cleveland, unaware of the second line.



Offline phlcontroller

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Controllers don't have a larger picture of weather?
« Reply #1 on: April 03, 2006, 03:45:31 PM »
If you as a controller have 30 miles between cells, that's alot of room for airplanes to land in between the first cell leaving and the second cell blowing through. CB.

Offline KSYR-pjr

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Controllers don't have a larger picture of weather?
« Reply #2 on: April 03, 2006, 03:48:21 PM »
Quote from: phlcontroller
If you as a controller have 30 miles between cells, that's alot of room for airplanes to land in between the first cell leaving and the second cell blowing through. CB.


Is it so much room that an aircraft that has minimum fuel doesn't need to know about the second line?

Offline Biff

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Controllers don't have a larger picture of weather?
« Reply #3 on: April 03, 2006, 04:04:02 PM »
30 miles is a long way.  Even if the cell is moving at 30mph, that gives them an hour before it gets there.

I don't know what 'minimum fuel' means exactly, but guessing that means he wants to get on the ground in less than an hour.

Offline KSYR-pjr

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Controllers don't have a larger picture of weather?
« Reply #4 on: April 03, 2006, 04:29:56 PM »
Quote from: Biff
30 miles is a long way.  Even if the cell is moving at 30mph, that gives them an hour before it gets there.


Understand, but in this case the cells were reportedly moving about 50-60 kts.   So, about 1/2 hour until arrival.   The SWA that called was still 110 miles out, which at some point he would have been indicating 250 kts or less (10k or below speed limit), or perhaps 20 minutes out.

Given some vectoring in line with other arriving aircraft, it is not that hard to imagine that the second line could be a problem.

Quote from: Biff
I don't know what 'minimum fuel' means exactly, but guessing that means he wants to get on the ground in less than an hour.


Minimum fuel was my choice of words.  The pilot did not declare minimum fuel, but more or less implied it since he stated he needed to land without holding or extensive vectoring (essentially this is what declaring minimum fuel means).

The idea for this topic here stemmed from this and numerous other examples I have heard on various feeds (NY, Detroit, Toronto, to name a few) over the last year where I hear ATC and pilots trying to figure out a way to fly around a line, but neither having a complete radar picture of the advancing front.  It seems that if one or both had a more complete picture, a more effective avoidance strategy could be developed.

I was speaking with a JetBlue pilot who told me that JetBlue is looking to install satellite-downlinked radar sometime soon that will give them exactly this tool.  

Now that thunderstorm season has started here in the US, I recommend watching a radar mosaic site, such as Intellicast, then listening to a feed where the airport is about to be overtaken by a line of t-storms.  See if pilot and/or controller suggests an avoidance strategy that does not necessarily account for the bigger picture that you see on the radar (i.e "Request 010 heading for the next 10 miles to see if I can get around this line" when in reality a level 4 to level 5 line of precipitation extends north about 100 miles or so).

Offline KSYR-pjr

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Controllers don't have a larger picture of weather?
« Reply #5 on: April 03, 2006, 05:38:49 PM »
This is what the radar image looked like of the two lines moving into the area:



(image copyright Intellicast and all that...)

Offline hopskip

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Controllers don't have a larger picture of weather?
« Reply #6 on: April 03, 2006, 10:32:14 PM »
from what I understand, the pilot basically said if he's not down on the first approach (within 30 mins) then theyre going to Cleveland. In which case the second cell 30 mins away is somewhat irrelivant.

Offline Pygmie

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Controllers don't have a larger picture of weather?
« Reply #7 on: April 04, 2006, 12:26:44 PM »
I don't know about how things work in the U.S., but up here in Canada we have no access to weather radar data while in position.  All our "avoidance stratagies" are based on pilot reports.  Not sure if the U.S. controllers get weather radar fed to their control positions, but we sure don't up north so we really have no idea how far a line extends unless the pilots relay this information to us.

Offline KSYR-pjr

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Controllers don't have a larger picture of weather?
« Reply #8 on: April 04, 2006, 12:57:12 PM »
Quote from: Pygmie
I don't know about how things work in the U.S., but up here in Canada we have no access to weather radar data while in position.  All our "avoidance stratagies" are based on pilot reports.  Not sure if the U.S. controllers get weather radar fed to their control positions, but we sure don't up north so we really have no idea how far a line extends unless the pilots relay this information to us.


Thanks, Pygmie, for the first-hand account.  As a controller, do you believe that a Doppler radar feed displayed at your position or even a central location that can be seen by all controllers would better serve you when assisting pilots during thunderstorm season than just the precipitation levels you see displayed on your scope?

Based on two tours of the approach/tower facilities at my local class C airport in central NY state, I can only speak for this facility when I point out that the only weather these controllers have is that displayed on their scopes.  

This facility is running the relatively new STARS software on all scopes in the approach facility, which I understand displays precipitation levels in color versus the old, monochrome format.  However, the weather picture these controllers have is only based on their radar site (and, of course, AWOS and PIREPs), not that of a mosaic of Doppler radar sites that could give them a big picture view.

Offline KSYR-pjr

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Controllers don't have a larger picture of weather?
« Reply #9 on: April 04, 2006, 01:15:42 PM »
Quote from: hopskip
from what I understand, the pilot basically said if he's not down on the first approach (within 30 mins) then theyre going to Cleveland. In which case the second cell 30 mins away is somewhat irrelivant.


Flying down the ILS to a landing in less than 30 minutes is only half of the picture.  A prudent pilot would also consider how much time would be needed to go missed and be vectored away from the airport to their alternate.  

You will note in the radar GIF I posted above that the second line of thunderstorms was more than one cell, and therefore most likely impenetrable.  Circumvention would have been the only option and that, of course, adds more time and uses more fuel than planned.

BTW, I applaud the fact that the SWA pilot decided while still 100 miles out to go to their alternate rather than attempt an approach at BUF with minimum fuel and thunderstorms about.   In my opinion, had there been a downlinked radar mosaic in their cockpit in addition to active radar, the pilots would have been even more confident in their choice to divert to the alternate.

Offline bwicker

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Controllers don't have a larger picture of weather?
« Reply #10 on: April 06, 2006, 02:21:59 AM »
Just a side note:  The radars the controllers have in front of them are fairly limited in noticing weather.  The have so many filters on them to filter out random stuff that it's difficult for them to pick up WX except for strong storms, and even then all they can tell is rainfall.  In order to get this kind of info from a controller, especially a center controller you have to ask them for it, and there's a WX3 key which will show slashes where rain is falling at a little over .1" an hour, and H's where the rain is .2-.3"/hr.  Also, I know all centers have a CWSU (Center weather service unit) assigned to them, you can't talk directly to that person, but they're there updating the controllers on current wx conditions.  However, i'm not sure if approach facilities have a dedicated weather person on staff at all times.  I was just doing a little research and the newer ASR-9 radar can actually see the WX and classify it according to it's intensity.  But I believe most approach contol facilities aren't up to ASR-9 yet, so they're limited in their weather reporting ability.  If there are any controllers here who can add to that or correct anything on this let me know, i dont want to be handing out false info.  That's just from some of the little research i did on the subject.

Offline phlcontroller

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Controllers don't have a larger picture of weather?
« Reply #11 on: April 06, 2006, 11:14:10 AM »
At the PHL tracon I have 5 different levels of weather intensity. We use the ASR-9. I cannot tell the type of precip. but it is a nice display because we use STARS. It's not the old sweeping radar display it's a digitized display. We also use the ASR-11 radar via a feed from NXX depending on what sector we are working. CB.

Offline w0x0f

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Controllers don't have a larger picture of weather?
« Reply #12 on: April 07, 2006, 11:12:19 AM »
PIT uses ASR 9 on a STARS display for local weather at the controller's position.  There is also Doppler radar which goes out to 50 miles.  There are 2 Doppler displays in the TRACON, one at each end of the room from which a controller can get general information at his position.  He would have to get up and walk to the display to see specific details such as gust fronts and microbursts.  There is also the Traffic Situation Display or TSD.  This is a traffic management tool which also displays national weather radar information.  There are 2 of these displays at each end of the TRACON which may be customized to show variable ranges of weather from local to national scales.  The traffic management unit at the back of the TRACON also has a weather predictor which projects out to 2 hours into the future on weather movement.  I'm not sure which equipment they have at BUF, but the flight crew would have received a better answer if they were landing at an airport with all of PIT's equipment.  Each facility is different.  There are no standards for minimum weather equipment.  

w0x0f