KFC 150

[jackn]

As a new Mooney pilot, I'm still getting aquainted with my new M20K Encore. When I have the A/P on(HDG & ALT), then turn the heading bug >30 deg, sometime(not all the time) in the turn, I will feel a strong G load & A/P will disconnect! This never happens when I'm watching carefully, although I have seen ALT excursions of more than 70 ft during the turn. Any thoughts?

[carusoam]

Jack,

Welcome aboard...

There should be a limit to the bank angle that the KFC 150 will go to.  If I remember correctly, it is slightly steeper than standard rate.  The angle is stated in the supplement that should be in your POH.  Unfortunately, I left my POH in the plane this weekend, or I would have written it here.

For comparison, I have not had KFC 150 cause a load up on Gs, cut out or change altitude either...

Suggestion, check POH for maximum bank angle, compare to actual bank angle...

Hope this helps get you going in the right direction...

Best regards,

-a-

[jackn]

Thanks for your comments. The bank angle stays constant(approx. 20 deg). Was wondering if the Mooney's electric trim just has trouble keeping up with the changing fwd/back pressure needed, when it does 'catch up' it may exceed the accelerometer in the A/P.

[carusoam]

Jack,

Just a guess, but based on what you are saying, mixed with very little experience...

Take a look at how smoothly your trim wheel is operating (by hand).  When my plane went through its pre-purchase inspection, it had a significant amount of hardened grease removed from the trim system.

It sounds like it is possible that the KFC is commanding a change in trim (or roll), followed by resistance to that change.  When resistance is sensed by the KFC, it turns itself off.

I am not familiar of an accelerometer based cut out of the KFC.

The KFC will turn off, by pushing the red button, or the AP switch, or by overpowering the servos (just try to touch the trim button).

On start-up, the KFC tests the status of all system parts including the electric trim and servos.  If they are not working properly enough for the test, the KFC beeps annoyingly until you remove power from it.  However, it does not test the full extent of travel of the servos.

I think some cleaning and new lubrication in the right area may be helpful to identify your situation.

Hope this helps

Best regards,

-a-

[jackn]

Your suggestions sound very reasonable. Thanks so much!

Jack

[jackn]

Traced the problem to my Garmin 696 mounted on the yoke. Too heavy. In a climb the back momentum was overpowering the servos, then A/P cut out. Need to find a better way to mount it.

[carusoam]

Jack,

Interesting find.  Thanks for the follow-up.  Putting these things on the yoke is convenient, but not always the best idea.

 

Best regards,

-a-

[DaV8or]

I personally hate yoke mounts, but as a renter it's pretty much your only good solution and it is easy and quick. As an owner (someday soon) I will not have any yoke mounts.

[jackn]

Anyone have a suggestion on best place to mount a 696. Don't have the room to mount in the panel.

[Earl]

Quote: jackn

Anyone have a suggestion on best place to mount a 696. Don't have the room to mount in the panel.