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KAP/KFC 150 installation differences?


Oldguy

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Another Mooney pilot is pulling his KFC 150 to replace it with a GFC 500 and has offered it to me. I currently have a KAP 150 tied into my Aspen. I also have the KAS 297B and KEA 136 similar to what many KFC 150 installations have. 

I told him I did not think it was as simple as a swap out and add a few wires, but I actually have no idea. Can someone explain the differences in the installation to a non-electrical engineering mind? I do not want to pass up something like this if it is feasible to do with relatively a small effort, but also don't want to rip my panel apart to add a FD to the Aspen.

TIA.

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Make sure they are the same voltage: most are 14V but some are 28V. 

I believe the only differences between the KAP and KFC 150s are the computer and the attitude gyro. There would be some wiring additions between the KI256 and the KC192 to connect up the flight director. Once that’s done, connecting the Aspen FD is only a few wiring changes according to the Aspen install manual. I would talk to someone that has actually done this, but from the diagrams it doesn’t look complicated.

I’m not sure what paperwork you would need to make the installation legal. Another good question for a avionics shop. 

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Command bars on the AI... a new modern AI probably would make a nice upgrade...

Computer with the KFC... with the FD button on it...

BK used to have their pilot catalogs and details online...

from the 90s... that detailed all the part numbers that went together... in the various systems...

 

Everything looked like individual components...

But... they were so well integrated...you would never select various parts to integrate separately... until you had to... 

 

Now... you can probably do it just for sport... with the availability of pre-flown parts...

 

This is where I usually mention Alan...

:)

Best regards,

-a-

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On 3/13/2021 at 11:52 PM, carusoam said:

 

Everything looked like individual components...

But... they were so well integrated...you would never select various parts to integrate separately... until you had to... 

 

Now... you can probably do it just for sport... with the availability of pre-flown parts...

 

A few months ago I asked the question here on the practicality of adding altitude select to a KAP 150. I received replies which stated that it would be an intense project because (among other things, including an encoded altimeter and paired attitude indicator) the computer needed to be calibrated for the added equipment as well as other hard wired configuration changes. I had been under the (mistaken) impression that I could simply get a shop to install the KAS 297 and that I'd have the feature instantly available. Wrong.

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I asked my avionics guy the same thing.  Figured with everyone upgrading there would be some KAS-297a units available at a good price.  But the final price kept climbing as you added all the parts needed and the installation time.  So decided to stick to just the altitude hold.

But on a side note...  I couldn't remember "KAS-297a" so I was googling it and ran across a Aspen preselect for the KFC-200.  Not sure if this is new or if I just never saw it.

https://aspenavionics.com/products/aps4a-altitude-preselect/

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There isn't a huge difference between the KAP 150 and KFC 150 autopilots.  The only difference is the flight director.  The aspen is built to simulate the KI 254/256 and can use the same commands to drive the flight director.  It should only be a handful of wires added to add the flight director function.

Here are the connections from the KFC150 the KI indicator.

image.thumb.png.b2468750690c5dec8406f865b9043e14.png

And, here is from the Aspen manual showing which connections are needed for the flight director.

image.png.79e0f1dac2cc69fc4e8574bb847b70b7.png

It should relatively easy (of course it is a Mooney and the panels can be a nightmare to work on) to add the five wires that support the flight director operation.  The flight director adjustment is done through two small adjustment pots that can be accessed through the front panel of the KFC150.

Good luck and I say, go for it.

Warren

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And I would say if you don't want to go for it, let me know, and I will give it a shot! I had looked at this similar topic when installing an Aspen 2000 MAX system. I do know that you can't just take any 'ole KFC and swap out the box, as there are 'chips' inside calibrated to the different airframe models (Mooney, Piper, Cessna, etc...) That and the voltage difference as mentioned above. If you don't want it, tell them you know someone who is. 

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To provide some clarification, the main difference from a KAP150 to KFC150 is the addition of FD bars and a different AI.  There is additional wiring as others have mentioned but don't forget about the voltage of the unit or the adapter chips that are airframe specific.  Depending on how the aircraft is optioned the KAS297B can be additional as well as a remote annunciator.  Also, the KC192 flight computer needs to be married/aligned to the attitude source.  This is easiest to do with the flight line tester or if the shop has built a extender harness as all of the gain pots are on the right side of the unit and you can not adjust them if they are in the rack.

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I believe one of them needs to be change and I want to say it is the top module. I would have to look at the install manual to be sure.  As for paperwork I think you could use the original stc install paperwork as it covers all the KAP/KFC for that aircraft/model.  However, be sure to consult your local shop first just to stay safe.

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On 3/17/2021 at 7:54 AM, Jake@BevanAviation said:

To provide some clarification, the main difference from a KAP150 to KFC150 is the addition of FD bars and a different AI.  There is additional wiring as others have mentioned but don't forget about the voltage of the unit or the adapter chips that are airframe specific.  Depending on how the aircraft is optioned the KAS297B can be additional as well as a remote annunciator.  Also, the KC192 flight computer needs to be married/aligned to the attitude source.  This is easiest to do with the flight line tester or if the shop has built a extender harness as all of the gain pots are on the right side of the unit and you can not adjust them if they are in the rack.

Thanks! The potential unit is coming out of a 252, so the main takeaway from your comment for me is validating the voltage. I already have the 297B with the KAP, and the shop that would do the work is a repair station, so my assumption is they have the necessary harness.

Now to check on the STC paperwork and see if I am covered. If it looks like I am, I will talk with the shop to see if they agree and go from there.

Thanks again.

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3 hours ago, Oldguy said:

Thanks! The potential unit is coming out of a 252, so the main takeaway from your comment for me is validating the voltage. I already have the 297B with the KAP, and the shop that would do the work is a repair station, so my assumption is they have the necessary harness.

Now to check on the STC paperwork and see if I am covered. If it looks like I am, I will talk with the shop to see if they agree and go from there.

Thanks again.

Are you installing it in a J? The K and J have significant elevator/trim system differences (J was the last model with the trim assist bungees and the K was the first with the downspring and bobweight) so there might be different characteristics to the autopilot. The are two modules that plug into the computer PCBs that are specific to each airplane model. If switching models, you should check that the modules don't need to change, or that if they do, the modules from your KC 191 will work in a KC 192.

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