Help problems with KAP 140 AP

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Army Frank
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Help problems with KAP 140 AP

Post by Army Frank »

Hello, this is Army Frank owner 04 DA-40 w/G1000. KAP 140 AP heading works occasionally, altitude ok. When heading works its a few degrees off from heading bug. The heading work for about an hour or so then wont hold holding. This problem has happened when temperatures have reached 90 or more. Hope to hear from someone soon. Thank you
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Re: Help problems with KAP 140 AP

Post by Rich »

Army Frank wrote: Sun Aug 16, 2020 6:31 pm Hello, this is Army Frank owner 04 DA-40 w/G1000. KAP 140 AP heading works occasionally, altitude ok. When heading works its a few degrees off from heading bug. The heading work for about an hour or so then wont hold holding. This problem has happened when temperatures have reached 90 or more. Hope to hear from someone soon. Thank you
I'm inclined to think the roll servo is at fault, as we know servos do fail. How does it behave in NAV and ROL mode?
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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Army Frank
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Re: Help problems with KAP 140 AP

Post by Army Frank »

Hello Rich, thank you for getting back to me. I have never engage the ROL mode. When I engage the AP, I set the heading bug and engage the HDG, NAV and ALT buttons. Sometimes the AP works the first time, other times is takes a few attempts to work. I reset the CB All three message HDG, ALT & NAV illuminate when it works. I have reached out to Honeywell/King. no help other than them sending me a trouble shooting manual. Appreciate your ideas thank you. Frank
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Re: Help problems with KAP 140 AP

Post by Rich »

Here is something simple to try: Pull out the flight computer and re-seat it. You need a 3/32" allen wrench to unlock it. Pull it out, push it back in and re-tighten using the wrench to re-lock it in place.

There are diagnostics that can be used to inquire what the computer is seeing, but you need to get a laptop with terminal mode and appropriate cable to get to the information. Frankly, it's likely best to get with a Bendix/King guy to deal with it if it comes to that.

Has it always behaved like this?
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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Army Frank
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Re: Help problems with KAP 140 AP

Post by Army Frank »

Rich,
This problem just started. In the spring I installed a 0 time engine and everything forward of the firewall is new. I'm currently breaking in the engine. Similar posts suggests nulling. Honeywell suggests that because the AP acted up in 90 degrees the problem maybe its too hot and the cooling fan can't keep the AP cool. Thank you for responding. I will try your idea. Thanks Frank
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Re: Help problems with KAP 140 AP

Post by Lance Murray »

King KAP 140 has a fault log. You can plug into it with a laptop. You will need to make a cord that is described in the King KAP140 maintenance manual
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Army Frank
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Re: Help problems with KAP 140 AP

Post by Army Frank »

Hello Lance,
I communicated with Honeywell/King and they told me the same thing. Thank you for getting back to me. Frank
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Roxi5m9
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Re: Help problems with KAP 140 AP

Post by Roxi5m9 »

Army Frank wrote: Sun Aug 16, 2020 8:05 pm Hello Rich, thank you for getting back to me. I have never engage the ROL mode. When I engage the AP, I set the heading bug and engage the HDG, NAV and ALT buttons. Sometimes the AP works the first time, other times is takes a few attempts to work. I reset the CB All three message HDG, ALT & NAV illuminate when it works. I have reached out to Honeywell/King. no help other than them sending me a trouble shooting manual. Appreciate your ideas thank you. Frank
Hey Frank, hope you don’t mind, would like to give you some autopilot pointers. When you engage the autopilot, it is in ROL mode by default (keeping your wings level) and Pitch mode (keeping your nose level). ROL, HDG, and NAV are called lateral modes. Just FYI, if you are already on your course, you can just directly engage NAV, but good practice it to have your heading bug matching the heading you are flying, engage heading and then engage nav as it positively transfers over to using the autopilot properly when you are not already on your course and need to intercept it.

This doesn’t help you with your mechanical issue, but hopefully it helps you understand your flight guidance functionality a bit.
N597RA 40.444
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5M9, Marion, KY
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Rich
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Re: Help problems with KAP 140 AP

Post by Rich »

Roxi5m9 wrote: Mon Aug 31, 2020 1:46 pm When you engage the autopilot, it is in ROL mode by default (keeping your wings level) and Pitch mode (keeping your nose level).
The initial mode is ROL and VS (Vertical Speed). That is, it will seek to maintain the current vertical speed, whatever that may be at the time you engage it. (It's not uncommon to engage the AP on climbout. You wouldn't want it to level off while climbing in the soup.) This isn't an important factor for this discussion, just clarifying.
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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Army Frank
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Re: Help problems with KAP 140 AP

Post by Army Frank »

Hello Nick,
Thank you for responding. I spoke to two avionics shops and they have identified the possible problem as a minor adjustment, using a screwdriver to make adjustments on the KAP 140 or a software issue. I plan to post the fix. Thank you ArmyFrank
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