Wind Shear/Airmet Tango Moderate Turb

Discussion in 'Pilot Training' started by CC268, Dec 12, 2017.

  1. CC268

    CC268 En-Route

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    Hey guys,

    I was thinking about flying today after work as it was a nice clear, calm day. Went on ForeFlight, Aviation Weather Center, windy.com, etc to do a little preflight briefing. To my surprise I see an Airmet Tango for moderate turbulence from the Surface-10,000 feet as well as a forecast for wind shear at 1500 feet -100 @ 30 knots.

    So I decided to not fly. My understanding is that this happens due to a temperature inversion and may not indicate turbulence at all. In fact, it could be very smooth. But that paired with the Airmet Tango for moderate turbulence sort of tied up the deal for me.

    Any thoughts, tips, info is appreciated.

    Thanks.
     
  2. Pilawt

    Pilawt Final Approach

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    FWIW, I flew from Goodyear down toward Gila Bend at about 9 this morning. If I remember correctly, the winds aloft forecast for Phoenix at 3,000 was 100º at 21 knots, which seemed about what I was experiencing at 2,000 - 3,000'. That kind of forecast would seem to justify the Airmet Tango, but where I was it happened to be smooth.

    And on the ground at KGYR it was dead calm.

    The NWS Forecast Discussion up now says this:

    East winds should be maintained through the afternoon and evening with a 25-30kt easterly LLJ developing after sunset. Sheltered valley location may experience some LLWS this evening as the boundary decouples, though conditions will be somewhat marginal and winds speeds in the 1-2K ft level will decrease by sunrise. Winds should finally obtain a westerly direction Wednesday afternoon.
     
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  3. CC268

    CC268 En-Route

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    Well gonna try to fly after work tomorrow. Looks like it should be another nice day. Oh well
     
  4. danhagan

    danhagan Cleared for Takeoff

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    You need to get out with a CFI in some real stiff winds (30+). You're in a similar area, so there's going to be mechanical TB off the mountains, learn how to circumvent it. If you scrub flights for every airmet tango in the desert SW, you're going to miss a lot of the smooth days also (as Pilawt said) where it is was an over call. You're going to get the reverse some time as well, where winds are supposed to be calm, and you get the snot kicked out of you.

    I scrubbed in the Tiger if winds were 40+ at mountain ridge elevation. An old instructor told me to calculate the mountain elevation from ground and divide by two to determine the "nasty zone" during high wind (e.g. Franklin mountains 7500 MSL field elevation 4000 MSL = 3500/2 (which works out to 1700 over the mountain or 9200 MSL and above to get away from the SUPER huge upsets). On long XC in high wind with a large ridge (Guadalupe Peak), you'll feel mechanical TB upto 30 miles downwind lee side. I hit a 70 knot head wind near Guadalupe once and it was glass smooth (just slow) - later in the flight over El Paso, I made the mistake of descending early and really got a ride.
     
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  5. WannFly

    WannFly Pattern Altitude PoA Supporter

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    I had the same q a month back, it's airmet T most do the times here and the air is glass smooth. Rt now I am highly confused with when to pay attention to T

    Sent from my SM-G935V using Tapatalk
     
  6. F01LA

    F01LA Pre-takeoff checklist

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    Up 'til now my method has been:

    Windy at the surface? Probably turbulent
    Airmet Tango? Probably smooth, but you never know.

    I've gotten a lot more interested in trying to figure out turbulence from Skew-T graphs and the Aviation Weather Center: http://aviationweather.gov/gfa (select Turb then choose your altitude).

    In my experience (one flight so far) the Skew-T was quite accurate about turbulence and what altitudes it was at. You might check into these.
     
  7. WannFly

    WannFly Pattern Altitude PoA Supporter

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    i use the GFA tool on a regular basis and so far it has been pretty accurate. need to learn that Skew-T
     
  8. Clark1961

    Clark1961 Touchdown! Greaser!

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    Weather in the vertical parts 1 & 2 by Ed Williams are pretty good vids if ya learn that way. My normal learning method is read and do but that just didn’t work for me with skew-t. The vids made it stick.
     
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  9. Lndwarrior

    Lndwarrior Pre-takeoff checklist

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    Every once in a while the Airmet Tango is for real.

    I, too, pretty much discounted them unless there were pilot reports or high surface winds (from ASOS/ATIS) to support the possibility. This was because they are such a frequent occurrence here in northern California and, time and again, I would take off and find little or no turbulence.

    A few months ago I had the most terrifying flight of my life (25 years of flying) after taking off, with my wife. It was in fact "moderate turbulence" which threw my little plane around like a rag doll. It was so bad I could not read a chart or access airport data on my ipad.

    I tried landing at a number of airports and the turbulence was just so severe I could not get the plane down safely and had to abort the landings. Finally I flew to the longest runway around, told the tower I was having trouble, and literally had it in mind to "crash the plane as slow as possible".

    Somehow I got the plane on the ground in one piece.

    I take a much closer look at the Airmet Tango reports now...
     
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  10. PaulS

    PaulS Final Approach

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    I flew yesterday to Westchester, NY, weather much better than forecast, but it was bumpy below 3,000 as forecast. I'm getting checked out in an SR-20 but hadn't been up in 15 days due to weather, schedule and mechanicals. Anyway I was in a slight right turn aligning to a 2 mile final with an impressive cross wind, wind shear had been forecast. Well, turns out the wind shear forecast was correct, the airspeed dropped from about 90 knots to 70 trending downward, pretty much instantaneously , at this point the instructor asked for the airplane, applied full throttle and we landed uneventfully. This was a learning experience for me, first in the cirrus, visually, aurally and by the seat of my pants, I did not feel that airspeed change, I've had this before in other AC but there were other clues as to what was happening. Secondly, I'm not sure I would have gone full throttle to recover, which my instructor probably understood hence the reason why he asked for the airplane. We were right where we wanted to be vertically before the shear event, he applied full throttle, for at least 5 to 10 seconds, the result was we stayed on the glideslope. So my takeaway on this, it reinforced for me, the need to keep an eye on airspeed in the pattern, especially in this airplane, near the ground, especially on a gusty day. Finally, from this day forward, I will not hesitate to firewall the throttle in a situation like this until things improve, you can always pull it back.
     
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