Autopilot Replacement Question

[Bob - S50]

Our KFC200 has electric trim.  If it turns out to be more cost effective to replace the KFC200 with the TruTrak than it is to repair our pitch servo, I have a couple questions.

1.  Can we legally keep the electric trim from the KFC200 even though it would no longer be our autopilot?

2.  Assuming we want to keep the KI256 (AI) and KI525A (HSI) until they fail, what parts can we legally remove?  I'm guessing the control panel and the annunciator would have to go, but does the computer have to stay for the HSI to work?  That is, does the HSI get its course and glideslope info through the computer or does it get the information directly from the (in our case) GTN650?

Obviously, the pitch and roll servos would be replaced by the TruTrak servos.

Thanks in advance for any collective knowledge.

Bob

[gacoon]

I too have been trying to figure out next steps on autopilots as I have a Century 2000 driven by an Aspen unit.  The Aspen is OK, fonts are small for my taste but it works.  The Century is near end of life and does not work right and needs to go.  So I have been looking at a lot of new stuff in anticipation of some changes.  RC Allen has a nice new Attitude indicator/Backup Battery System that would let me go all electric.  Autopilots are to the tough choice.  Trutrak is nice in the experimental world, I had one in my previous Exp plane and it was awesome - but the new certified one in my mind in its present configuration with STC limitations wont cut it for IFR - cant use it for approaches, does not couple to VOR/LOC/ILS, wont fly a heading, limited to 700agl - also presently does not have trim capability.  They are working on a Aspen interface and when that comes out we'll see which of the current limitations are removed - I'll wait till then and its good go with them or rip it all out and go with the new Gamin stuff.  So if all you want is an en-route autopilot Truktrak is great.

>1.  Can we legally keep the electric trim from the KFC200 even though it would no longer be our autopilot?

More than likely - does the electric trim manually work if the autopilot is shut off.  Lots of airplanes have electric trim and no autopilot.  You would be required to eliminate the autopilot connection to the trim motor.

>2.  Assuming we want to keep the KI256 (AI) and KI525A (HSI) until they fail, what parts can we legally remove?

KI256 could remain as a standalone AI not hooked up to anything.

HSI can certainly be kept, autopilot connection disconnected and its just like any other HSI system without autopilot.

> I'm guessing the control panel and the annunciator would have to go, but does the computer have to stay for the HSI to work? 

No, HSI is an output to autopilot, inputs to HSI are power, compass heading from magnometer and Nav signals from VOR/GPS systems

>That is, does the HSI get its course and glideslope info through the computer or does it get the information directly from the (in our case) GTN650?

From the GTN650.

If it were me I wouldn't remove the old autopilot until you were ready to install a new one - I think two separate steps would be extra labor.

Gerry

 

 

[Bob - S50]

Hey Gerry, long time no see.  We used to have our plane across the alley from yours.

From a response I got on Beechtalk, it may be that the electric trim runs through the flight computer.  That is, there may not be a direct link from the trim switch to the trim servo.  If that is the case, we would have to leave the computer in place for the trim to work.  That would be disappointing and make it impractical to replace the KFC with the TruTrak if we still want electric trim.

[gacoon]

On mine I have electric trim that works with the Century autopilot, or separately just as an electric trim.  I have an on/of rocker switch for the trim.  Can you trim the aircraft with the autopilot off?  If so, try pulling the circuit breaker on the master autopilot controller and see if the trim will work manually.  I know mine works separately so if Trutrak comes up with a solution their trim can be interfaced to the trim motor.

[Bob - S50]

We have an electric trim switch/CB that will turn off the trim.  Pull the autopilot CB and the trim quits then too.  I should have thought about that before I even asked the question.  Guess I'm out of luck.

[gacoon]

12 hours ago, Bob - S50 said:

We have an electric trim switch/CB that will turn off the trim.  Pull the autopilot CB and the trim quits then too.  I should have thought about that before I even asked the question.  Guess I'm out of luck.

You might ask an Avionics shop knowledgeable in King autopilots if the trim can be decoupled into a standalone unit?