KAP140 Autopilot Pitch Fault

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Rick
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Re: KAP140 Autopilot Pitch Fault

Post by Rick »

Victor wrote:I found this statement in DA40 G1000 AFM supplement:

"No altitude information or altitude preselect settings are exchanged between the
autopilot and the G1000 system. Altitude and barometric setting entries must be
made separately on the G1000 and KAP 140 autopilot systems as appropriate"

so looks like they are not talking altitude at all...
Yeah, I don't understand why the KAP doesn't take the barometer and altitude settings from the G1000 - that would be a nice touch. But if it's not getting current altitude either, then why is it even connected to the G1000 - I wonder what it IS getting? It has to be more then just the audio output. Time to hunt doen some drawings...
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Re: KAP140 Autopilot Pitch Fault

Post by Jean »

Rick wrote:
Victor wrote:I found this statement in DA40 G1000 AFM supplement:

"No altitude information or altitude preselect settings are exchanged between the
autopilot and the G1000 system. Altitude and barometric setting entries must be
made separately on the G1000 and KAP 140 autopilot systems as appropriate"

so looks like they are not talking altitude at all...
Yeah, I don't understand why the KAP doesn't take the barometer and altitude settings from the G1000 - that would be a nice touch. But if it's not getting current altitude either, then why is it even connected to the G1000 - I wonder what it IS getting? It has to be more then just the audio output. Time to hunt doen some drawings...
It gets heading (heading bug) in heading mode and nav information (cdi) in nav mode.
40.446, G1000, KAP 140, Hartzell Metal
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Re: KAP140 Autopilot Pitch Fault

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Jean wrote:It gets heading (heading bug) in heading mode and nav information (cdi) in nav mode.
Duh - what was I thinking. GS reference, too. Thanks for setting me straight, Jean. :oops:
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Re: KAP140 Autopilot Pitch Fault

Post by Rick »

Just as an update, this problem doesn't seem to be cold-temperature-related. Well, actually it seems to have gotten much worse now that it's warmer! The last few flights, the Pitch fault light comes on as soon as the KAP140 hits the power-up test #3. If I cycle the AP CB maybe 10 or 12 times, it will eventually pass test #3 and be fine, but it is annoying to say the least.

So... the plane goes to the avionics shop Monday to address this problem. I'll post the results as soon as we figure it out.

Thanks for all the good advice, everyone - I've learned a lot about the AP.
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Re: KAP140 Autopilot Pitch Fault

Post by Victor »

Looking forward to your findings. I am too getting pretty frustrated since even with the warm weather finally here its a hit and miss with error at step 3 (way more miss that hit).
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Re: KAP140 Autopilot Pitch Fault

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Back from Virginia Aviation at KLYH. The tech pulls the log from the KAP and we find a ton of "error 33 - accel mon over upper lmt" messages - pretty much one for every time we've powered up the avionics lately, including the flight over to LYH this morning. His idea is to replace the KAP140 and make sure the problem is really in the box and not the pitch servo. He doesn't have one handy, but he pulls ours out to copy the s/n down anyway. After replacing the unit, it powers up fine. 5 times in a row. Works fine on the flight home, too. :scratch:

Do I believe that somehow re-seating the KAP somehow "fixed" this problem? Maybe bumping the accelerometer around during the removal & reinstall somehow freed it up?
:tap:
I have this nagging feeling we haven't seen the last of this problem. For now, I guess we'll just wait and see. If (when) it fails again, we'll go back for a swap and see what happens. Does anyone know if Honeywell has a swap program like Garmin does, and if so, how much for the KAP140?
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Re: KAP140 Autopilot Pitch Fault

Post by Rich »

Rick wrote:Back from Virginia Aviation at KLYH. The tech pulls the log from the KAP and we find a ton of "error 33 - accel mon over upper lmt" messages - pretty much one for every time we've powered up the avionics lately, including the flight over to LYH this morning. His idea is to replace the KAP140 and make sure the problem is really in the box and not the pitch servo. He doesn't have one handy, but he pulls ours out to copy the s/n down anyway. After replacing the unit, it powers up fine. 5 times in a row. Works fine on the flight home, too. :scratch:

Do I believe that somehow re-seating the KAP somehow "fixed" this problem? Maybe bumping the accelerometer around during the removal & reinstall somehow freed it up?
:tap:
I have this nagging feeling we haven't seen the last of this problem. For now, I guess we'll just wait and see. If (when) it fails again, we'll go back for a swap and see what happens. Does anyone know if Honeywell has a swap program like Garmin does, and if so, how much for the KAP140?
Specifically, this is the KC 140 module. The KAP 140 is a system consisting of the KC 140 and the servos and other stuff (in my case a HSI 525 and magnetometer).

Upon upgrading to WAAS I had to reseat the KC140 afterward, as somehow the pins didn't fully seat. That was something like 3-4 years ago. The only problem since was a loose connector at the KI525, easily remedied.
2002 DA40-180: MT, PowerFlow, 530W/430W, KAP140, ext. baggage, 1090 ES out, 2646 MTOW, 40gal., Surefly, Flightstream 210, Orion 600 LED, XeVision, Aspen E5
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Re: KAP140 Autopilot Pitch Fault

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Rich wrote:Specifically, this is the KC 140 module. The KAP 140 is a system consisting of the KC 140 and the servos and other stuff (in my case a HSI 525 and magnetometer).
Good point, Rich - thanks for the correction.
Rich wrote:Upon upgrading to WAAS I had to reseat the KC140 afterward, as somehow the pins didn't fully seat. That was something like 3-4 years ago. The only problem since was a loose connector at the KI525, easily remedied.
What were your simptoms when your KC140 wasn't seated - completely dead, or some partial functionality? I suppose it's possible that one or two poorly-connected pins were causing our problem, and reseating the unit 'fixed' it. I'm still skeptical, though...
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Re: KAP140 Autopilot Pitch Fault

Post by Victor »

I am thinking of a possibility of slight pin corrosion resulting in extra resistance which triggered failure during the test... going to try the same trick on thursday....
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Re: KAP140 Autopilot Pitch Fault

Post by Rich »

Rick wrote:
Rich wrote:Specifically, this is the KC 140 module. The KAP 140 is a system consisting of the KC 140 and the servos and other stuff (in my case a HSI 525 and magnetometer).
Good point, Rich - thanks for the correction.
Rich wrote:Upon upgrading to WAAS I had to reseat the KC140 afterward, as somehow the pins didn't fully seat. That was something like 3-4 years ago. The only problem since was a loose connector at the KI525, easily remedied.
What were your simptoms when your KC140 wasn't seated - completely dead, or some partial functionality? I suppose it's possible that one or two poorly-connected pins were causing our problem, and reseating the unit 'fixed' it. I'm still skeptical, though...
Not completely dead, but it's been many years and I don't recall precisely.
2002 DA40-180: MT, PowerFlow, 530W/430W, KAP140, ext. baggage, 1090 ES out, 2646 MTOW, 40gal., Surefly, Flightstream 210, Orion 600 LED, XeVision, Aspen E5
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