Garmin GTN with Aspen PFD Questions

GarmAspen

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Jul 22, 2013
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GarmAspen
I posted on another thread that I am looking to upgrade my plane with a Garmin GTN/Aspen combination. I am fortunate that a friend of mine recently upgraded his to a similar configuration and I had a chance to fly it last night. The airport is uncontrolled and out in the country a bit, so I was able to self navigate.

My question pertains to timing and when to do what. I first flew the Aspen using his second, older Nav unit to receive the ILS signal. With VLOC2 selected and vectoring myself on final outside of the FAF, the AI popped up the vertical and lateral deviation indicators and we flew a conventional ILS approach. Where things got a bit unsettling was when I tried to use the GTN.

Scenario:

After shooting the ILS using the VLOC2, I began the left climbing turn towards the holding pattern for the miss. About 2 miles south of the airport, I selected and loaded the ILS approach on the GTN. I picked vectors to final, selected GPS1 and began flying to an IAF. I then activated the approach. What happened next was baffling. The GTN switched to VLOC, I lost the GPS1 signal on the Aspen and was able only to select VLOC1 and VLOC2. VLOC2 still had the ILS freq on it, so I understand why that would be available. What was strange was that VLOC1, when selected, the AI popped up a lateral deviation indicator that showed a BC1 next to it.

Questions:

> Was I flying too close to the localizer signal and the Garmin thought I was trying to fly the back course? Reading the manual, I understand the automatic CDI switch from GPS to VLOC, but I did not expect it to do that on the back course. Is this normal?
> I was able to get the GPS signal back by touching the CDI button, but when I touched the CDI, VLOC1 was available of the Aspen, but the BC1 stayed until I cleared the flight plan and reloaded the approach. Is this normal? Or could I have done something differently to prevent it from doing the automatic switch to VLOC?
> On flight planning, it looks like you need to select your route, including your destination airport. You then select the approach for the airport, presumably when you know which approach is in use. This puts it at the end of the flight plan and leaves the destination airport in the flight plan before the approach. Is it expected that you delete the destination airport once you select the approach? Or is there a better way of doing this?

Thanks for any help! I like what I am seeing so far. There is soooo much packed into that combination.
 
The BC was due to you selecting the arc mode on the Aspen rather than the HSI display mode. The CDI is BC because you were still in the outbound direction and the CDI is a simple L/R indication, whereas if you had chosen HSI display mode, the L/R aspect would have been taken care of by virtue of the course pointer being turned upside down.

I hate doing an ILS with an LPV available, it is so much simpler.
 
Thanks for the reply John. When you say "Arc" mode are you referring to the 100 degree mode you can select as opposed to the 360 compass rose with the HSI in the middle? I was pretty certain we did not change to that mode, but for all I know, I might have fat fingered it for a moment.
 
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Hi John. I found the section in the manual that talks about the Arc mode and the back course notation on the scale in the HSI area.

The ARC CDI Compass mode’s CDI and Scale are located at the bottom of the lower display. The indicator is a green diamond, and the scale is a set of four hollow, white dots with a white index mark at the center (Figure 4-59). When in the ARC CDI Compass mode, on a Localizer Back Course approach, a BC label is presented to the left of the scale, and the indicator corrects for reverse sensing (Figure 4-60).

This is not what I was seeing. The BC1 indication was actually next to the lateral deviation scale on the AI. The HSI was in the 360 mode. Any ideas?
 
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