Electric Trim Test

[mooneykflyer]

I fly a 231.

I keep hearing there's a Mooney procedure that is supposed to be performed on the trim prior to flight.

Many folks have said its in the POH yet I cant seem to find it.

Anyone know where to locate this 'mysterious' practice?

[jlunseth]

There are procedures that involve the electric trim, that are for the AP.  My AP is a KFC200.  They are in the supplement for the AP. The only other test is to run the flaps down at the beginning of your preflight, I suppose so that bolt connections etc. are visible.  In my aircraft everything is covered so about the only function of that test is to see that the flaps work.

[j3gq]

Assuming you have an electric trim installed, like on many Mooneys, you may want to rotate
your trim wheel before the electric (A/P) is powered. Check how much force is needed.
It should rotate fairly easy.
Forces may lincrease with time (for a few reasons) and at some point will make the electric
trim motor work too hard with effects on it's lifetime. Have the necessary adjustments
done soon, the trim motor is expensive.

AJ

[jetdriven]

My 1977 201 electric trim has stopped working.

 

When we first bought it all was well. Lately the electric trim has gotten intermittent and the wheel is getting harder to turn. Now it does not work at all.  We cleaned the switch with contact cleaner to no avail.  Does anyone have any experience with these units, and does anone have any service info on them, or the manufacturer and model number?

[davbert]

I recently had to pull the trim motor and trim drive shaft from my 77 20J.  The symptoms were sluggish electric trim and stiff manual trim wheel.  It got to the point where I had to help the electric trim by graunching on the manual trim wheel when trying to trim.  There is a pillow bearing adjacent to the chain sprocket on the trim drive shaft.  That bearing was in need of lubrication.  Cleaning and lubricating the bearing solved the problem.  Should be three to four hours of labor.

The preflight trim test is meant to test the split trim switch.  Move each switch segment up and down individually and ensure that the trim does not move.  The switch is split to ensure that no single contact failure (by contact welding) can cause runaway trim.

[Wistarmo]

Jlunseth is correct.   There is a flight manual supplement for the autopilot that should be in the POH.  The test has four parts:

           1) Move the left half of the electric trim switch forward and aft, ensuring that the trim wheel does not move; manually move the trim wheel to make sure the required force is normal                                                                                                            2) Repeat with the right half of the electric trim switch                                                                                                              3) Engage the autopilot and move the controls to ensure that they can be overridden, and                                                          4) Depressing the autopilot disconect switch, ensure that the electric trim switch does not move the trim.

These are found in the supplement in the POH for my M20J MSE with a KAP 150 autopilot.