My trim system failed yesterday!

[RV10Rob]

Great story, Pierre. An issue like you had is one reason I do stop-and-go's instead of touch-and-go's in the -10.

-Rob

[pierre smith]

I keep thinking about the return trip from Key West, in IMC, the last flight before the one where the trim system failed. Perhaps the trim system failed DURING that flight and we simply didn't know it!

It was on the next flight that I discovered the failed system, with a more forward CG since I was solo.

All of you guys need to check every single control system from a point of origin to the final attach point, during every condition inspection. Look at one rudder cable from the pedal to the rudder and all points in between. Do the same for the elevator pushrods...inspect every attach point and jamb nuts at each point all the way from the stick to the elevator.... remember the -10 that recently lost elevator control during his flare?

Do the same for all the controls and especially the engine controls.

Best,

[Mike S]

I normally move all the control surfaces on my preflight, but from now on my walkaroung will include checking the trim tabs for movement, instead of just moving the elevators.

Thanks for posting, glad you are OK.

[woodmanrog]

This is one reason I do my conditional inspections as a progressive rather than all at one time. I usually take at least two months to complete the inspection. this way it makes it easier on my back and joints and I am able to be more thorough while inspecting each section. I do the inspections during the week so that I can fly on the weekends. I believe that most experimental guys tinker with thier planes all of the time anyway so why not inspect smaller areas when there is tinkering downtime?

[Rotorheadrob]

I like the idea of a progressive inspection plan. Keeps the plane available without a longer down time. Does anyone have "a plan" that seems to work well?

[jjconstant]

Glad you're O.K. Pierre! Am I remembering correctly that there are now castellated nuts that have the nylon stopnut material in them? Belt and suspenders for those critical fasteners...I'm doing my condition inspection now and might have to find a few of those...

Thanks for the heads up in general and glad you shared this with us.

[Jesse]

Originally Posted by pierre smith

All of you guys need to check every single control system from a point of origin to the final attach point, during every condition inspection. Look at one rudder cable from the pedal to the rudder and all points in between. Do the same for the elevator pushrods...inspect every attach point and jamb nuts at each point all the way from the stick to the elevator.... remember the -10 that recently lost elevator control during his flare?

Do the same for all the controls and especially the engine controls.

Best,

I make the control systems a major inspection item at every condition inspection also. I grab the pushrods and twist and verify that they hit a hard stop both ways as the rod ends hit the edge of the bell crank. This will verify good jam nut installation and no loose bearings. I once saw a DAR catch an aileron pushrods wing root bolt missing a nut on an aw inspection. That's scary (although not as scary as if it had been an elevator pushrod). I also have found an auto pilot pushrod with loose jam nuts that could have twisted itself off either end, which could have ended in a very bad day with jammed ailerons. Control connections and the big fan in front are my biggest concerns. Got to keep the pilot from sweating too bad.

[Janekom]

Thanks for sharing Pierre and we are glad that you are OK.
Annual coming up this week so I will surely check those as well.

[douglassmt]

I must confess that I missed this pivot bolt on my just-finished first annual inspection. It is hard to see without either crawling WAY back in the tail cone, removing the entire elevator trim assembly, or (what I did last night) using a borescope to check it. Mine was correctly installed and in place but I must once again give kudos to this site and its honest and open contributors (only $25/year, are you kidding me?!!).

My thoughts on this event and the other recent (and more serious) control-system disconnect incident: I am going to make a list of every single control system linkage, bolt, rod-end bearing, jam nut, pivot bolt, etc. in the entire plane - according to where it is accessed (there really aren't that many). At every single oil change, I will open one or more of these access panels and look things over - such that I put an eyeball on the entire list in a year. This might be overkill but for a new plane it seems like an easy and simple way to effect a PM schedule. Since I wouldn't be touching anything unless something is amiss, I hope not to be susceptible to the Waddington effect.

I would be happy to post/share my list of control linkages for anyone else to use/comment on/improve.

[pierre smith]

Bryan, you just made my day. I told my wife, Jenny, the other day, that if only one guy checks his airplane's trim system and all the other controls, it would make the few minutes it took to make the post worthwhile.

I'm reminded of the approach Kahuna and the team take to inspect each other's airplanes...a great way to go about it.

We're family here and these kinda findings really ought to be shared.

Best,