GNC300 Question

[Morpheus122]

I just started instrument training in my RV-6A. I am having an issues flying holding patterns, esp after a missed approach.

The manual says to set the course on the HSI inbound to the holding fix. My problem, the GPS doesn't seem to know the radials for the hold. Once I cross the holding fix and try to do a teardrop entry, the CDI has reverse sensing. Is there a way to enter the inbound holding course to the fix on the GPS?

Thanks,

David T.

[BobTurner]

Are you in the "OBS" mode?
The inbound course should be entered on the obs or hsi.

[60av8tor]

Page 87-88 of your manual. I'm assuming, since you're conducting instrument training, that you have an annunciator. After hitting direct/enter to receive guidance to the MAHP (ensuring to follow MA procedures), you will have to hit the GPS sequence button to place it on hold - the same as the OBS (suspend) button on the 430. Then as the previous poster stated - adjusting your OBS/HSI for the inbound course.

[Morpheus122]

We have an annunciator and a external CDI. The CDI is a Terra Tri-Nav C. It will only display course deviation left and right.

After the missed approach point I:

1. Hit D-> and enter to sequence direct to the MAHP
2. Set the annunciator seq switch to Hold
3. Then enter the holding pattern as appropriate
(Our first try was a teardrop, upon intercepting the inbound leg the CDI was reverse sensing.)

Does the GNC300 have an internal OBS that I can tune the inbound holding course?

Otherwise I'm assuming we need to switch to an HSI or OBS with glide-slope

Also, the GPS/Nav annunciator switch doesn't control the CDI's data/input source. The CDI has a switch on the front that picks either vor1 or gps/loran.

http://www.terraavionics.com/forms/T...n%20Manual.PDF

[Morpheus122]

Ok so I think this explains my issue, sideline of page 60.

It seems like my CDI cant talk to the GPS to pick a course radial.

So after pressing direct to it gives me the option to select a course.



So once I arrive at the MAHP, I need to goto the CDI page and select the inbound course as I would with a VOR??

[60av8tor]

I've never used this particular CDI, but looking through the manual, I would ensure that the to/OBS/fr/bc switch is set to OBS, and that you aren't accidentally using a reciprocal course (reverse sensing). BTW, you do have a glide slope indication on that unit.

[Morpheus122]

The GPS sends the signal to the Loran C readout. This happens when the switch on the right is in the LRN position. When in this mode, the OBS only functions as a course reminder.

The OBS selector is for tuning in VOR radials.

[60av8tor]

Originally Posted by Morpheus122

Ok so I think this explains my issue

So once I arrive at the MAHP, I need to goto the CDI page and select the inbound course as I would with a VOR??

Good find. This very well could be the issue. This would explain the reverse sensing if you are set to the inbound course to the MAHP and it doesn't change once you cross over and turn back on the inbound leg of the hold. Yes, looks like you would need to set the course through the GPS. Kind of a pain, but should be ok once used to the button pushing sequence...

[Morpheus122]

So it seems that we need a conventional OBS/HSI that can talk to the GPS?

[Morpheus122]

And the built in CDI has an arrow that shows TO and From. I need to pay attention to that. Im only use to seeing it pointing up=TO