Multiple approaches

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Posts: 29
Joined: Thu Mar 14, 2013 1:10 pm

Multiple approaches

Post by Clam »

Today I flew multiple practice approaches using the HXr driven by a Garmin 430W. The flight plan and nav mode source are set to external. The system performed flawlessly during a full procedure turn. I then "EXECUTED" the approach on the HXr when established inbound. The system displayed lateral and vertical deviations to DA as expected.

I flew back out and attempted two of the exact same scenarios but could not get the GPS vertical deviations and the "EXECUTE" softkey never illuminated after the first approach.

I reloaded and activated the approach on the 430W as I did on the first approach and it populated in the HXr flight plan.

Is this a switchology problem? Do I need to do something in the HXr to get the "EXECUTE" option to become available for subsequent approaches? The GPS lateral deviations functioned as expected.

RV-8 Memphis, TN (KFYE)
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Joined: Mon Mar 11, 2013 6:34 pm

Re: Multiple approaches

Post by Bobturner »

I replied on VAF, but just so there’s an answer here too:
Once you push execute the approach is ‘locked in’ to the GRT. This is so, if you have a non-gps missed approach procedure, you can go ahead and enter that into the GRT after ‘execute’. The changes won’t take effect until you push ‘missed’. On the VAF post you said you never pushed ‘missed’; that left the original approach locked in. At least, this is how I understand the system.
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Joined: Tue Dec 11, 2012 12:11 am

Re: Multiple approaches

Post by GRT_Jeff »

If the 430W is sending vertical deviations then the EFIS should display them as long as the EFIS is still in a GPS mode. Approach mode isn't required to display the deviations, only to capture them and command the autopilot and flight director to follow them down to the runway. Could the 430W have been accidentally switched to another mode, or have been suspended (SUSP)? The 430W won't send the vertical deviation until it knows it can advance to the final approach segment. I would think when you loaded and activated another approach it should have reset back to how it was with the first attempt.

EXECUTE mode should reset when the approach mode on the EFIS is cancelled, which has to be commanded on the EFIS by the MISSED button, or switching the ARM button to OFF, or an incompatible mode change (switching away from a GPS mode). If the ARM mode isn't cancelled, the EFIS will stay in execute mode from the previous approach attempt. It's not smart enough to figure out that the approach was restarted.
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