KAP140 Autopilot Pitch Fault

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NickBudd
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Re: KAP140 Autopilot Pitch Fault

Post by NickBudd »

Further to my recent post, the avionics shop at Diamond advised that the problem was a corrupted software package in the KAP 140 and when reloaded it worked fine. They said this happens sometimes with the KAP 140 and no one knows quite why. I had a brief but comprehensive test flight followed by a 4 1/2 hour trip uback home in some difficult turbulence, and no further problems.
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Re: KAP140 Autopilot Pitch Fault

Post by wolfvoador »

Hello, same result here: did the 100hs in Wr. Neustadt, they updated the Config Mod, and adjusted / partly replaced roll servo (Eur 3,000...), and I just crossed Siberia with this, no problems any more!
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NickBudd
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KAP 140 Pitch Failure

Post by NickBudd »

After two months of sitting on the apron in cold weather and numerous drains on the battery while the starter motor was changed, I found the KAP 140 would not boot up (stuck on stage 3 with a red P, a familiar issue discussed in this forum). Someone in the hanger said "Oh, I had that problem on my Mooney when the battery was low. Let's plug in a booster cable." With the booster the KAP 140 cycled right through to the end. So when the AP start up stops at stage 3 before engine start, try again when one of the engines is running.
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jb642DA
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Re: KAP 140 Pitch Failure

Post by jb642DA »

NickBudd wrote:
Wed Jan 16, 2019 2:22 pm
After two months of sitting on the apron in cold weather and numerous drains on the battery while the starter motor was changed, I found the KAP 140 would not boot up (stuck on stage 3 with a red P, a familiar issue discussed in this forum). Someone in the hanger said "Oh, I had that problem on my Mooney when the battery was low. Let's plug in a booster cable." With the booster the KAP 140 cycled right through to the end. So when the AP start up stops at stage 3 before engine start, try again when one of the engines is running.
Been awhile since flying/owning our DA42 but - Isn't the KAP140 autopilot powered up off the Avionics Master Switch (ie: On after engine start?) Or is it powered via the Electric Master?
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Rich
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Re: KAP 140 Pitch Failure

Post by Rich »

jb642DA wrote:
Wed Jan 16, 2019 7:49 pm
NickBudd wrote:
Wed Jan 16, 2019 2:22 pm
After two months of sitting on the apron in cold weather and numerous drains on the battery while the starter motor was changed, I found the KAP 140 would not boot up (stuck on stage 3 with a red P, a familiar issue discussed in this forum). Someone in the hanger said "Oh, I had that problem on my Mooney when the battery was low. Let's plug in a booster cable." With the booster the KAP 140 cycled right through to the end. So when the AP start up stops at stage 3 before engine start, try again when one of the engines is running.
Been awhile since flying/owning our DA42 but - Isn't the KAP140 autopilot powered up off the Avionics Master Switch (ie: On after engine start?) Or is it powered via the Electric Master?
That's a good point. Typically I don't fire up the avionics bus until after engine start. But there are times I will do so without starting the engine, such as double-checking that the nav data cards I just swapped into the GNS units are correct.
2002 DA40: MT, PF, 530W/430W, KAP140, ext. baggage, 1090 ES out, 2646 MTOW, 40gal., Surefly, Flightstream 210.
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Re: KAP140 Autopilot Pitch Fault

Post by NickBudd »

My practice has been to boot up the avionics before calling for clearance to start engines so I knew everything is working. According to the AFM this is the correct procedure, but some people are reluctant to do this for fear that a power surge from the alternators will fry something in the avionics.
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Re: KAP140 Autopilot Pitch Fault

Post by Rich »

NickBudd wrote:
Wed Jan 16, 2019 8:32 pm
My practice has been to boot up the avionics before calling for clearance to start engines so I knew everything is working. According to the AFM this is the correct procedure, but some people are reluctant to do this for fear that a power surge from the alternators will fry something in the avionics.
Ah, there you go. In the US or Canada I've never had to get clearance to start the engine, though in some places before taxiing it's required to get clearance.

Just double-checked and the DA40 manual shows powering up avionics AFTER engine start.
2002 DA40: MT, PF, 530W/430W, KAP140, ext. baggage, 1090 ES out, 2646 MTOW, 40gal., Surefly, Flightstream 210.
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Re: KAP140 Autopilot Pitch Fault

Post by OliverBucher »

In Europe you need a clearance „start up“ to start your engine for every IR-Flight.
I personally have a „cold weather“ procedure to start the engine before the start up and IR-clearance. But this is not official.
Greetings Oliver
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Re: KAP140 Autopilot Pitch Fault

Post by NickBudd »

I stand corrected, the proper procedure is to turn on the avionics master after engine start. When I took the introductory DA40 course in 2005 the folks at Diamond had AV master on the prestart checklist because they said there is no risk of a surge so that’s what I do. I noticed this has changed in the DFC London Operating Checklist. If I had followed the official procedure I would not have had a scare with the AP boot up, so from now on this is what I will do. Thanks Rich for pointing this out.
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Re: KAP140 Autopilot Pitch Fault

Post by nrenno »

The KAP 140 of my 2005 DA40 started giving a pitch trim error when booted. After reading the excellent comments in this post and trying some of the simpler steps unsucessfully, I asked my mechanic to remove the pitch trim servo. The servo was sent to Duncan Aviation for repair. They discovered that the servo's strain gauge had failed. The strain gauge was replaced and the service was shipped back me and installed in the plane by my mechanic.

After installation the KAP pilots completes the diagnostics without any error. Everything appears to be working correctly, but when the autopilot is turned on in flight, it pitches the plan down instead of holding the attitude. Does anyone know if this issue can be easily corrected via a laptop connected to the KAP 140?

Thanks!!!
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