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Heading giving odd readings during IFR training

Printed From: Avidyne
Category: Avidyne General
Forum Name: IFD 5 Series & IFD 4 Series Touch Screen GPS/NAV/COM
Forum Description: Topics on Avidyne's IFD 5 Series and IFD 4 Series Touch Screen GPS/NAV/COM
URL: http://forums.avidyne.com/forum_posts.asp?TID=1925
Printed Date: 20 Sep 2020 at 5:00pm
Software Version: Web Wiz Forums 12.01 - http://www.webwizforums.com


Topic: Heading giving odd readings during IFR training
Posted By: 260SE
Subject: Heading giving odd readings during IFR training
Date Posted: 09 Jan 2020 at 9:34pm
So I’m early on in my IFR training and today was another session of partial panel work.  I’m using my whisky compass and my IFD-540 for heading info.

So during slow flight and especially power-off and power-on stalls, the heading readings almost acted like they were “tumbling”.  Heading was spinning around with no rhyme or reason.  The only thing I can come up with is that we had 50-60 kt winds aloft while flying at 40-50 kts, and we were at times getting “negative” 10-15 kts ground speed (i.e., moving backwards).  Maybe the heading has some vector or ground track component to it?  It’s not hooked up to my magnetometer.  In writing this, I think that may be the answer - it’s ground track and not heading that is being displayed.  Someone please confirm?



Replies:
Posted By: teeth6
Date Posted: 09 Jan 2020 at 9:37pm
My IFDs show track



Posted By: oskrypuch
Date Posted: 09 Jan 2020 at 10:26pm
You can select heading (if you have appropriate inputs) or track. In the settings panel.

* Orest


Posted By: Bob H
Date Posted: 09 Jan 2020 at 11:51pm
Originally posted by 260SE 260SE wrote:

So I’m early on in my IFR training and today was another session of partial panel work.  I’m using my whisky compass and my IFD-540 for heading info.

So during slow flight and especially power-off and power-on stalls, the heading readings almost acted like they were “tumbling”.  Heading was spinning around with no rhyme or reason.  The only thing I can come up with is that we had 50-60 kt winds aloft while flying at 40-50 kts, and we were at times getting “negative” 10-15 kts ground speed (i.e., moving backwards).  Maybe the heading has some vector or ground track component to it?  It’s not hooked up to my magnetometer.  In writing this, I think that may be the answer - it’s ground track and not heading that is being displayed.  Someone please confirm?
Per your post in Topic: Compass on IFD?, glad you now have the IFD setup to display your track.  You should be careful about terminology.  Heading is the direction the nose of the aircraft is pointing and track is the direction the plane is moving.  I know you know this, but the distinction is important when using the display while flying.  Throughout this thread, you refer to heading info and heading readings, yet you do not have heading information presented (based on your magnetometer comment).  So, think about what happens to your track when you go forward, then backward, sideways, or stand still.  Displayed track is based on GPS position change calculations.  So, it will jump around and be unstable trying to sort out all the position changes that don't line up nicely in a single direction.  It's very rare to see something like that, but it seems you encountered the perfect conditions for it.  Your instructor should have been able to explain this to you.  Also, from my perspective, partial panel should not include using the GPS track or heading function.  Partial panel is a worse case scenario and using the GPS display is basically no different than using your DG.

Good luck with your training!  It is an exciting time in your airplane journey!


-------------
Bob


Posted By: 260SE
Date Posted: 09 Jan 2020 at 11:58pm
Thank you!!!!



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