Flying an Offset Hold On a GTN

If you were assigned an unpublished hold by ATC today, would you know what to do?  Furthermore, if the hold was beyond the last waypoint in your flight plan, would you know how to make it work?    With the Garmin GTN™ touchscreen avionics or GTN Xi series navigator, this can be easily accomplished with just a few extra keystrokes to configure a normal user hold.  The key elements are:

1. Setting a COURSE TO the NAVAID.
2. Assigning an along-track offset waypoint.
3. Establishing a user-defined hold. 

These elements will be listed and described below.  

Let's use a scenario to discuss how this is accomplished.  You are in a Cessna 182 (N12GM) with a GTN 750Xi installed. You are currently 3000ft over Lawrence Municipal Airport (KLWC) in Lawrence, Kansas and navigating to the Topeka (TOP) VORTAC.  

SITUATION

ATC contacts you on the radio saying, "N12GM, hold west of the 5 DME fix, Topeka VORTAC, 270 radial, 4 mile legs, expect further clearance at 0529Z.  Continue heading 294 and advise when able to proceed direct to the hold."

NOTE: In this situation, the hold is beyond the last waypoint in the flight plan.   Along track offsets can only be established after waypoints that have another waypoint following.  The GTN cannot set up an along track offset beyond the last waypoint in a sequence because there is no defined track.  (i.e. An along track offset could be after point A if there is a point B.  It could not be after point A, if point B does not exist in the flight plan).

Due to this fact, we must establish a COURSE TO the fix in order to establish an along track offset.

PROCEDURE

1. Setting a COURSE TO the NAVAID : First, we must establish the COURSE TO the waypoint.  Since the ATC directive is a vectored heading, ensure that you hand fly or have your autopilot set to HDG and 294 degrees during the duration of this configuration.  If you have the Autopilot set to NAV, you will deviate from the example ATC clearance.

   
   

2. Select the Direct To key and choose COURSE TO.  Enter "090" and activate.  ATC has told us to hold on the 270 radial FROM.  In order to achieve this, we have to tell the GPS to set up a COURSE TO the reciprocal in order to get the same result.
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3. This will reveal the map page.  Visually verify that you have an indefinite line from the west to the east, terminating at the TOP VORTAC.
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4. Assigning an Along Track Offset Waypoint. Second, assign an along track offset waypoint on this COURSE TO the TOP VORTAC.  Go to the Flight Plan page and select the TOP VORTAC waypoint.  Then select "Along Track".  
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5. Our ATC directive was to hold at 5 DME on the 270 radial.  Select "-5" and Enter. The "-" will always be assigned in the field when the mode is set to "Before".  Any time "After" is select, this will show as a positive number and set the along track waypoint beyond the target waypoint.
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6. You can see now that we have the offset established west of the VOR and on the correct radial.   Now it is just a matter of adding in the hold.
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7. Establish the User Defined Hold.  Select the offset waypoint "TOP -5".  Select "Hold At Waypoint".
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8. Configure the hold to meet the needs of the ATC directive.  The directive was  "Hold west of the 5 DME fix, Topeka VORTAC, 270 radial, 4 mile legs, expect further clearance at 0529Z".

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      1. Hold West of the 5 DME fix, 270 radial: The 5 DME fix requirement is already fulfilled, so it plays no role on this page.  The User Waypoint page is derived from GPS.  So to comply with a radial FROM, you must either enter the reciprocal COURSE TO, or choose Outbound.  (i.e. 090 inbound or 270 outbound).  It will yield the exact same result with the performance of the hold. 

         
         

      2. 4 mile legs: Select the leg type to "Distance" and the leg distance to "4nm".

         
         

      3. Expect Further Clearance at 0529Z: Enter the EFC time in the bottom field.  Verify all information on the hold page for accuracy before loading. Use a common sense check from the ATC directive.  "Hold West of 5 DME."  Verify the course lines (on) and the narrative (under) the map preview window are what you are expecting to fly.

   
   

9. Select "Load the Hold"
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10. Now everything is set up.  You are still heading 294 degrees and are ready to advise ATC you can go direct.  You inform ATC, and they respond, "N12GM, proceed direct to the assigned hold.

    
    

11. Select the Direct To soft key.  Ensure that you have the TOP -5 waypoint selected and select the "Hold Activate" hard key.  Now you can switch your autopilot to NAV for it to follow the new active navigation directive.  
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Remember, there is no replacement for researching in your Pilot's Guide and Aircraft Flight Supplement as well as some dual instruction with a good Flight Instructor.  You can find the digital document downloads for your GTN HERE.  

Always ensure you feel comfortable with these tasks prior to executing on an IFR flight plan, and especially in IMC. 

The iPad GTN Trainer App can be downloaded for free here.

You can view the Free GTN PC Trainer options at the bottom of this page here..