Garmin 430 how to deviate for weather, then return to FP

Discussion in 'Cleared for the Approach' started by jeffs chips, Jun 1, 2019.

  1. jeffs chips

    jeffs chips Filing Flight Plan

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    Hello, private pilot headed into IFR ticket and can't find a video or tutorial on how to deviate for weather (or anything) when on a garmin 430 flight plan, then, after passing obstacle, return to flight plan. Is it as simple as switching to heading mode, changing heading by say a certain amount of degrees, then once past the obstacle, going back to gpss mode and thereby getting back on course via autopilot?

    Thanks in advance.
     
  2. AggieMike88

    AggieMike88 Touchdown! Greaser!

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    The original "I don't know it all" of aviation.
    Yes.

    Switch to heading mode, take care of deviation.

    Then >D> ENTER ENTER to proceed from present position to the selected waypoint.


    Don't forget there is a downloadable sim that is perfect for playing with scenarios and questions such as this.
     
  3. benyflyguy

    benyflyguy Pattern Altitude

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    I like your method better if the deviation is small. Reason being is if your clearance is on a victor airway- leaving flight plan in will help your establish faster back on the airway.
    If you D->enter enter to next waypoint you aren’t necessarily going to be on the airway anymore.
    If you have a larger deviation your clearance might change a bit so the D- enter enter method is better.
     
  4. Heftiger

    Heftiger Pre-takeoff checklist

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    Right.

    There’s an accident chain video out there about this.
    A turboprop commander or something like that leaving Arizona at night with family onboard. Deviated for whatever reason and then D-> ent ent.

    Then later controlled flight into terrain. Not enough terrain clearance for the new route.
     
  5. AggieMike88

    AggieMike88 Touchdown! Greaser!

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    The original "I don't know it all" of aviation.
    Both of you guys I agree with if an airway was involved and terrain clearance was tight. So take care of the deviation, but be mindful how far off of the airway you are getting and how much clearance you have over the terrain. Then when deviation is sorted, use the NAV function of your autopilot and the OBS of the CDI to reintercept the radial. Once established back on airway, switch to GPSS and continue.

    But keep in mind, this is PoA and the interwebz, so picking of all sorts of nits is fair game. That said, the OP didn't specify airway. So.... nyah!:p:p
     
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  6. aterpster

    aterpster Pattern Altitude

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    Trying to stay below the PHX Class B airspace:

    https://www.flyingmag.com/news/ntsb-father-wasn’t-controls-doomed-turbo-commander
     
  7. jeffs chips

    jeffs chips Filing Flight Plan

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    All very useful and enlightening. Thanks for the link to the sad story. So the moral of the story is be aware of terrain clearance and obstructions at all times.
     
  8. luvflyin

    luvflyin Final Approach

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    Yup. Moral #1. The Big Moral. The HMIC (head moral in charge.) There are many other sad stories about not knowing where the rocks are and where you are.
     
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  9. luvflyin

    luvflyin Final Approach

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    That simple except there are times when you may not want to go back to gpss mode once past the obstacle. Sometimes ATC will clear you direct to a Waypoint up the up the road you already have loaded in your Flight Plan, then it’s easy. Sometimes they may want to vector you back to the route before then. Like “fly heading ###, join Victor##, resume own navigation. When you change back to gpss from heading mode will depend on the situation.

    EDIT: @jeffs chips , it just dawned on me I was thinking of GPS in general, not GPSS. Read below
     
    Last edited: Jun 2, 2019
  10. MauleSkinner

    MauleSkinner Final Approach

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    Isn’t it two pushes of the DIRECT button to activate the flight plan course to the fix rather than just going direct to the fix?
     
  11. luvflyin

    luvflyin Final Approach

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    I dunno. Just edited my post above. I’ve never used gpsS much less even any autopilot.
     
  12. Ravioli

    Ravioli Final Approach

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    I'd hit the FPL button, pick the segment I want to rejoin, and activate.

    [Note: I'm VFR only, but I do have to deviate to avoid them clouds I'm not allowed to fly through]
     
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  13. flyingron

    flyingron Touchdown! Greaser!

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    As I heard a testy controller state: "Resume own nav means go back to the assigned route, not direct to destination."

    If the fixes in your plan are close together, going Direct to the next one probably is as good as any. If they are sufficiently far apart, you'll probably have to give the thing a help. On my 480/Stec combo, I'd make sure the proper segment is still active and then set a heading that will put me towards where I want to intercept and punch both the HDG and NAV buttons which will follow the HDG until the intercept occurs.
     
  14. midlifeflyer

    midlifeflyer Touchdown! Greaser!

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    Yes. DIRECT gives to direct to the next waypoint; DIRECT DIRECT give you the flight plan leg interception.
    upload_2019-6-2_11-23-58.png

    Solution is easy. In the readback tell the controller what you are going to do. Let Mr Testy correct you if he wants, so long as yo are ultimately on the same page.
     
    Last edited: Jun 2, 2019
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  15. luvflyin

    luvflyin Final Approach

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    What does it pick for the interception angle. Some hard number like maybe 30 degrees? Depends on how far off and out you are?
     
  16. Ventucky Red

    Ventucky Red Cleared for Takeoff

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  17. chemgeek

    chemgeek Cleared for Takeoff

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    Unless you have GPSS installed, your autopilot will not automatically re-join the airway. WIthout GPSS, you would dial in a reasonable intercept heading from your current position, fly until on the airway, then turn to the appropriate airway heading before re-engaging the autopilot. My STEC-20 will not capture an assigned routing unless it is within +/- 10 degrees of the desired heading. If off by more than that, it may eventually capture, but not after a lot of seasick scalloping. I don't have GPSS yet, so I don't know how well it copes with a large cross-track error and a large intercept angle.

    When flying IFR, it's always good to have a sectional chart open (That's my default view on my EFB) so you can see the minimum safe altitude for the quadrant you are flying in. That way, if you are solid IMC making deviations, you at least know if you are safely above obstacles. ATC will normally help as well when you go off course for weather, but they are not PIC.

    If you want to go direct to the next waypoint instead of re-joining the airway or previous routing, it's always a good idea to confirm with ATC. Often, ATC will beat you to that request and just offer a clearance direct if in radar contact and you are above MVA.
     
  18. luvflyin

    luvflyin Final Approach

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    Be careful of what you might be calling minimum safe altitudes on Sectionals. I think your thinking of MEF’s. Those altitudes in each Quadrangle. It’s Maximum Elevation Figure. The height above the highest terrain in the quadrangle plus 200 feet for any uncharted obstructions plus 100 feet for error then round up. If the highest thing is man made obstruction then it’s that plus 100 feet for error then round up. That altitude could put you within 100 feet of something but it’s usually a little higher. If your using them as a minimum safe altitude for IFR you better be adding around a 1000 feet to them.
     
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  19. FORANE

    FORANE Pattern Altitude

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    On the GTN series one may choose to continuously display MSA on the screen.
     
  20. midlifeflyer

    midlifeflyer Touchdown! Greaser!

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    If you are going to intercept the current leg, you pick your intercept angle, just as you would without GPS. With an autopilot, you are already in heading mode for the deviation. Rotate to a reasonable intercept heading and, depending on the autopilot, arm nav mode or wait to switch to it when close enough for it to take over. A GPSS system might do most if it for you.
     
  21. jeffs chips

    jeffs chips Filing Flight Plan

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    thanks all. I think I've got it now!
     
  22. MD11Pilot

    MD11Pilot Line Up and Wait

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    If you are wanting to go back to the original course(why) you could also use the OBS function and have it Place the magenta line back...I.e. an airway
     
  23. George Mohr

    George Mohr Line Up and Wait

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    Yes, what you really want is the off-route altitude on the IFR Enroute charts.

    [​IMG]