Autopilot Checklist

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marioair
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Autopilot Checklist

Post by marioair »

I've noticed that the KAP140 and GFC700 autopilot checklist is subtly different:

KAP140:
  • DISCONN press, check electric trim not working
  • AP ON, check overpowering servos
  • DISCONN press, check AP of
GFC700
  • DISCONN press, check electric trim not working
  • AP ON, check annunciations and FD
  • DISCONN press, check AP off
  • GA button press, check FD commands climb, FD OFF
Why the difference? Specifically for the KAP140
1) Why do you not checked the FD
2) How do you check servo overpower - do you do a HDG and VS check seperatly
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Rick
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Re: Autopilot Checklist

Post by Rick »

Hi Paul,

WIth the KAP140, there is no FD or AP annunciators in the G1000, and no GA button, so the startup tests are going to be different. As far as overpowering the AP, you want to make sure you can manually force the stick in both the horizontal and vertical directions against the AP servos, just briefly. I also check to make the CWS button disengages the servos with the AP on.
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marioair
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Re: Autopilot Checklist

Post by marioair »

Rick wrote: Mon Mar 08, 2021 2:08 pm Hi Paul,

WIth the KAP140, there is no FD or AP annunciators in the G1000, and no GA button, so the startup tests are going to be different. As far as overpowering the AP, you want to make sure you can manually force the stick in both the horizontal and vertical directions against the AP servos, just briefly. I also check to make the CWS button disengages the servos with the AP on.
Thanks!

When you say there is no annuciators on DA42, assume you mean top-centre of the G1000 PFD, but it does actually show the FD itself when the AP is turned on

For manually forcing the servos, do you switch from ROL->HDG, command a turn and then try overpowering, or do you do it straight from ROL mode
For vertical, do you set ALT hold and overpower or put it in a climb/decsent first?

If you do the latter you're checking you can overpower the servo, but not that the servo's operate the trim's correctly?

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Rick
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Re: Autopilot Checklist

Post by Rick »

marioair wrote: Mon Mar 08, 2021 2:44 pm
Rick wrote: Mon Mar 08, 2021 2:08 pmHi Paul,

WIth the KAP140, there is no FD or AP annunciators in the G1000, and no GA button, so the startup tests are going to be different. As far as overpowering the AP, you want to make sure you can manually force the stick in both the horizontal and vertical directions against the AP servos, just briefly. I also check to make the CWS button disengages the servos with the AP on.
Thanks!

When you say there is no annuciators on DA42, assume you mean top-centre of the G1000 PFD, but it does actually show the FD itself when the AP is turned on

For manually forcing the servos, do you switch from ROL->HDG, command a turn and then try overpowering, or do you do it straight from ROL mode
For vertical, do you set ALT hold and overpower or put it in a climb/decsent first?

If you do the latter you're checking you can overpower the servo, but not that the servo's operate the trim's correctly?
Honestly, its been quite a few years since I owned a DA40 with KAP140, so I have forgotten which FD annunciation shows up on the G1000 (yes, top center of the PFD). And I currently have a DA40 with GFC, so I can't speak for the DA42 (although I believe it is the same as far as AP operations). But I know the AP annunciations for the KAP140 show up on the front of the AP itself, whereas the GFC700 AP annunciations show up at the top center of the PFD. As far as overpowering the servos, I don't think the AP mode matters (for either AP), as long as the servos are trying to hold the stick in place and you can still move it, with some force. This should be the case in any of the AP modes.
Roanoke, VA (KROA)
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Steve
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Re: Autopilot Checklist

Post by Steve »

For the older (non-G1000) DA40s. The KAP-140 comes on in ROL mode when you engage AP. Thus, that is the mode you are in when doing the AP check items in the checklist. Sometimes I am taxiing when I do this, it is interesting to see the stick try to correct the (small) deviations in heading while taxiing.
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Re: Autopilot Checklist

Post by ememic99 »

marioair wrote: Mon Mar 08, 2021 2:44 pm When you say there is no annuciators on DA42, assume you mean top-centre of the G1000 PFD, but it does actually show the FD itself when the AP is turned on.
Actually some KAP140 messages are annunciated on G1000 PFD (you'll see them during AP self-test and in flight if you have some AP failure). There's no FD on G1000 at KAP140 equipped aircraft.
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