DA40 G1000 GFC700 VNAV

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midlifeflyer
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DA40 G1000 GFC700 VNAV

Post by midlifeflyer »

This is a video I put together for my flying club. We have a 2007 DA40 XLS and a number of members asked questions about the function. Thought some here might be interested too.

Two links to the video. Content identical. Only the branding is different. And no monetization (no pop up ads) on either!

The club YouTube channel.

My YouTube channel.
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blsewardjr
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Re: DA40 G1000 GFC700 VNAV

Post by blsewardjr »

Thanks, a good explanation. Very sophisticated (and complex) system. With a lot of twisting and turning of knobs I can generate the same information on my GNS530W VNAV, which I then have to manually enter the VSR in the KAP140. As a result I rarely do this except I did recently for the descent to the IAF when I was 20 miles or so out and already cleared for the approach.
Bernie Seward, IR, AGI
2003 DA40 N377DS
KCHO Charlottesville, VA
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midlifeflyer
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Re: DA40 G1000 GFC700 VNAV

Post by midlifeflyer »

Yes. Most GPS navigators can produce the profile, with various degrees of difficulty. The problem is that not all autopilots are "VNAV savvy," which I think limits it's use.
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Boatguy
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Re: DA40 G1000 GFC700 VNAV

Post by Boatguy »

Well done! Nice demonstration. May I add a couple of points?

a) I find that on instrument approaches ATC picks my TOD, usually past the G1000 calculated TOD, and sometimes also specifies a higher crossing altitude than on the plate. However, the original descent is calculated based on cruise speed. Slowing to approach speed reduces the calculated descent rate and it can all work out, though sometimes I have to dive or even climb to intersect the VPTH slope.

When flying VFR this is not an issue and I can use the system's TOD.

b) There is an audible alert at 1min before VPTH which is a great time to punch the VNV button.

c) The APR button arms the approach which is very different than "activating" the approach. Activating makes the first waypoint in the approach the active waypoint. The APR button arms the FD to intercept the approach which may be VOR, LOC/GS or RNAV/GP.

Nicely produced and presented!

Thanks, Russ
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Re: DA40 G1000 GFC700 VNAV

Post by CFIDave »

Boatguy wrote:
Thu Nov 19, 2020 5:33 am
b) There is an audible alert at 1min before VPTH which is a great time to punch the VNV button.
If you punch the VNV button (i.e., arm VNAV) more than 5 minutes before TOD, the system will alert you at 1 minute before TOD by VPTH flashing white -- which is a reminder that you have to push the VNV button a 2nd time before TOD. (I don't recall any audible alert.)

However, if you arm the VNV button *within* (i.e., less than) 5 minutes before TOD, it will just work with no further attention necessary. When the plane hits TOD it will begin descending.

It works this same way on DA40/42/62 aircraft.
N62DV DA62 62.056
N42DA DA42-VI 42.N117 (sold)
N811ET DA40 XLS 40.874 (sold)
KJYO Leesburg, Virginia
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waynemcc999
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Re: DA40 G1000 GFC700 VNAV

Post by waynemcc999 »

Mark, very nicely done... thanks, and keep 'em comin'.
Wayne
Wayne McClelland
PPL/IR, 2008 Diamond Star DA40-XLS Supercharged 40.922, KSBA
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midlifeflyer
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Re: DA40 G1000 GFC700 VNAV

Post by midlifeflyer »

Boatguy wrote:
Thu Nov 19, 2020 5:33 am
Well done! Nice demonstration. May I add a couple of points?

a) I find that on instrument approaches ATC picks my TOD, usually past the G1000 calculated TOD, and sometimes also specifies a higher crossing altitude than on the plate. However, the original descent is calculated based on cruise speed. Slowing to approach speed reduces the calculated descent rate and it can all work out, though sometimes I have to dive or even climb to intersect the VPTH slope.

When flying VFR this is not an issue and I can use the system's TOD.

b) There is an audible alert at 1min before VPTH which is a great time to punch the VNV button.

c) The APR button arms the approach which is very different than "activating" the approach. Activating makes the first waypoint in the approach the active waypoint. The APR button arms the FD to intercept the approach which may be VOR, LOC/GS or RNAV/GP.

Nicely produced and presented!

Thanks, Russ
Yes, if I said "activate" instead of "arm" for the approach, I definitely may an oral typo.

And, of course, there is much more to the system and interaction with ATC. Changes in groundspeed mean changes in TOD. "Descend and maintain" means now, not when a calculated vertical profile decides to do it. I used an approach rather than a crossing restriction as a way of introducing it for my club for a few reasons including questions I received, particularly with the VPATH/GP transition. For example a lot of pilots were taught to descend to glide path intercept altitude after crossing the IF, descending, leveling off, and descending again instead of making only one configuration change, so I wanted them to see the autopilot's behavior following the VPATH.
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Re: DA40 G1000 GFC700 VNAV

Post by ZAV »

Really nice presentation. You explained the gotchas very well. Those are difficult to remember unless you use the VNAV function frequently. We mostly use the altitude selector as a reminder of what altitude we’re going to or where we’re staying. Therefore, it’s hard to remember that the altitude selector has a different function for VNAV use and it feels weird setting it for the bottom of the descent while we’re still flying level.
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midlifeflyer
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Re: DA40 G1000 GFC700 VNAV

Post by midlifeflyer »

ZAV wrote:
Fri Nov 20, 2020 4:05 am
Really nice presentation. You explained the gotchas very well. Those are difficult to remember unless you use the VNAV function frequently. We mostly use the altitude selector as a reminder of what altitude we’re going to or where we’re staying. Therefore, it’s hard to remember that the altitude selector has a different function for VNAV use and it feels weird setting it for the bottom of the descent while we’re still flying level.
Especially since, when hand flying, it's a general SOP bug altitude to make it easier to hold it.
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midlifeflyer
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Re: DA40 G1000 GFC700 VNAV

Post by midlifeflyer »

waynemcc999 wrote:
Thu Nov 19, 2020 7:11 pm
Mark, very nicely done... thanks, and keep 'em comin'.
Wayne
Thank you Wayne. As you already know, I did a number of videos this summer comparing different Garmin and Avidyne navigators doing certain real but less common tasks. If they include G1000, they are on the Odyssey page as well as my own. But I know that those who fly non-G1000 Diamonds (I flew my first DA40 in 2001) have done avionics upgrades and may find some of the other ones on the Midlife Flight channel interesting.
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