VFR Lateral Thunderstorm Separation???

Discussion in 'Cleared for the Approach' started by FlyingElvii, Dec 26, 2016.

  1. FlyingElvii

    FlyingElvii Pre-takeoff checklist

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    A question that turned into a discussion at work tonight:

    What is the minimum lateral separation from a thunderstorm while in VFR?

    After several opinions, including my own, "As far way as I can frikken get...", we consulted a FAAST circular, which stated 5 miles, but 20 miles is recommended.

    Now for the REAL question, which wasn't clear, and caused much chatter on a SLOWWW evening:
    Is that in miles, or nautical miles?
     
  2. Vance Breese

    Vance Breese Line Up and Wait

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    It depends on the size of the thunderstorm, where it is located and how fast it is moving.
    What you are flying makes a difference too.
    I stay 25 nautical miles from a big thunderstorm.
    I recently had hail bouncing off my knee board from a small thunderhead about seven miles away with blue sky overhead.
    Thunderstorms suck.
     
  3. Groundpounder

    Groundpounder Pre-takeoff checklist

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    There is no reg for distance from thunderstorms, just standard VFR cloud clearance rules would apply.
     
  4. FlySince9

    FlySince9 Pattern Altitude

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    Huh? Just being legal may not always smart... Hope you're solo when you test your theory...:rolleyes:
     
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  5. Groundpounder

    Groundpounder Pre-takeoff checklist

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    You're 100% correct, I was simply stating there is no reg regarding thunderstorm separation. Which is good, considering how many variables there are. A Florida afternoon airmass storm and a Midwestern frontal storm are two very different beasts.
     
  6. FlySince9

    FlySince9 Pattern Altitude

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    Nope... they can each kill you just as efficiently as the other...
     
  7. Groundpounder

    Groundpounder Pre-takeoff checklist

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    Yes and no. But it's always better to be safe than sorry, so your viewpoint is the more conservative one, especially without much experience dealing with weather.
     
  8. FlySince9

    FlySince9 Pattern Altitude

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    You think my opinion is based on lack of experience? Oh, no, Grasshopper...never assume...
     
  9. Groundpounder

    Groundpounder Pre-takeoff checklist

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    Well, I'll defer to your experience.
     
  10. Velocity173

    Velocity173 Final Approach

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    As said above, there is no reg for specific distance. The AIM recommends 20 miles. You make the decision based on experience.
     
  11. James331

    James331 Touchdown! Greaser!

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    Here's what I got.

    Don't mess with a cell, or get close to a cell that tops 30k

    Anything over 15k, should be seen as a big warning flag

    Keep a eye on the gradient, watch out of the steep ones

    50dbz = not going to have a good time

    Don't try to skirt downwind of a cell

    Keep 20nm from you and the cell

    If you're trying to top it, clear it by 1k for every 10kts of wind at the top of the buildup.
     
  12. Bill Watson

    Bill Watson Cleared for Takeoff

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    You are asking good and relevant questions but unfortunately you are going to find it an impossible to have such a discussion here.

    I got most of my convective storm experience racing sailplanes without the benefit of an engine let alone radar, Nexrad or even ATC radar.
    • The good part is that I had a chance to fly under and around convective storms in all 4 quadrants of the US.
    • The fun part is that those giant heat engines spew out a lot energy that at some particularly memorable times can be soared to great advantage. Unfortunately the opposite is also true - more often than not, they kill the race day.
    • The bad part is that I scared the bejeezus out of myself more than a few times - I can't say I recommend that approach to learning but it was invaluable.
    The last point is key; how do you learn without scaring or killing yourself? Certainly you want to digest everything written about storms and follow those guidelines until you get more experience. Soaring around storms was a unique experience but 2 things are applicable to VFR/IFR airplane flying:
    1. We flew a lot, as much as 9 out of 10 days straight, always right into the heart of the convective day. In airplanes, the best thing you can do is fly as much as often as you can so you can see as much weather and geography as possible.
    2. Hangar flying; we talked about each day's flight. Probably talked way too much about them but there was lots of hangar talk, every day. Hangar flying is quickly going out of style at most airports but i'd suggest that in the non-commercial pleasure flying context, the best thing you could do is to go flying with other pilots. Compare noted, combine forces, experience more weather in more aircraft, with more eyes. Even if you are ground pounder, hitching rides with other pilots will help build real skills.
    I can only imagine the skill building that 'freight dogging' offers. They fly all week, in all weather, sometimes aircraft that aren't always the best equipped. But you have to fly as a job to get that kind of experience.
     
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  13. Sundancer

    Sundancer Cleared for Takeoff

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    I use 20 miles, just cause it's worked for some decades. Penetrated a cell, in a
    C-130 (inadvertant, we were no-radar); it was violent to the point of loss of control. A Hurricane Hunter told me they didn't punch into cells, either, not on purpose.
     
  14. Clark1961

    Clark1961 Touchdown! Greaser!

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    Which side of the thunderstorm are you on? Upwind? Getting pretty close is usually okay. Downwind? Stay far, far away unless you like hail for some masochistic reason. No wind or not much wind? Dunno, never have seen that...

    Someone mentioned frontal thunderstorms. Be aware of the "dry line" thunderstorms of Texas and Oklahoma. The front will be a long way away to the north and you might think "no worries". After you encounter them you'll worry...
     
  15. MauleSkinner

    MauleSkinner Pattern Altitude

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    Plus, the turbulence will be much worse on the downwind side.

    It still amazes me how many professional pilots choose turbulence over smooth air. ;)