Gear binding when on the ground!

[Ben P]

Hi Folks! 

I'm new to the forum and appreciative for all of you fellow Mooney owners! I have a M20C 1976. Love it!

I turned my battery on today before startup, and a binding sound came from underneath the floor which felt very much like the gear actuator trying to lock the gear down in place! The gear handle was in the down position and the 'gear down' indication was illuminated on the floor prior to turning the battery on. I'd landed the night before with no problems, and it was a soft landing! Before shutting the battery off I noticed the gear down indicator that's usually illuminated green on the panel flickering on and off, which led me to believe it was trying to still lock the gear in place. After shutting off the battery, i checked the circuit breakers and nothing had popped. I jumped out and visually checked the gear and all was well. I went up in the wheel wells and all seemed normal with everything locked in place over center and all springs at normal length for gear extension. After putting her back in the hanger, I thought i'd turn the battery on one more time quickly to see if movement of the plane had allow full compression of the switch. After a one second period of binding you could hear the gear lock and both greens and no more binding.... we've just had our first freeze here in central texas and I'm wondering if the cold as anything to do with this? Will get it up on jacks tomorrow but figured I'd share this to see if anyone can shed any light? 

Many thanks!

Ben    

Edited December 2, 2020 by Ben P

[carusoam]

Welcome aboard Ben!

Let me start with that doesn’t sound right...

There is only one thing that sounds and feels like the gear motor moving in any Mooney...

It is not a normal occurrence to have the gear motor moving without it being commanded to move...

 

It would be wise to make sure the gear is down and locked before moving on to the next steps...

Having the gear collapse is terribly expensive...

Do you have a Mooney specific mechanic for this?

Checking the gear rigging and sensors, by an experienced person is highly recommended...

The flickering light is a great hint that at least one thing isn’t right...

PP thoughts only, not a mechanic...

Best regards,

-a-

 

[Dreamlifter]

Take a look at the emergency gear extension panel to make sure everything is in the correct position. 

Where in Central Texas are you located?

Steve

[RLCarter]

Welcome aboard, get it secured on jacks and see what’s going on. 

[Prior owner]

I would Put it on jacks and check the gear preloads before continuing to operate the gear. If the down limit switch is out of adjustment, the motor can start bending pushrods by continuing to run well past the point of sane preloads. And pull the belly panels and look at everything...

Edited December 2, 2020 by PilotCoyote

[Hank]

1 hour ago, PilotCoyote said:

I would Put it on jacks and check the gear preloads before continuing to operate the gear. If the down limit switch is out of adjustment, the motor can start bending pushrods by continuing to run well past the point of sane preloads. And pull the belly panels and look at everything...

Exactly! Troubleshoot gear issues where a malfunction won't hurt anything. 

[Ben P]

Thanks guys for your quick and informative replies. 

My A&P and I put it up on jacks, re-rigged the mains via the service manual, moved the thread on the down limit switch so the switch is a little nearer the stop, and all is well! 

Happy flying to you all!

Ben 

(Lockhart, TX)

[carusoam]

Great follow-up Ben!

That was fast. (Typical MSer... they all fly Mooneys)  

was there anything specific found while rigging the mains?

Best regards,

-a-

[Ben P]

Both of the push pull rods needed to be reset so that the bolt that passes through them at the aft end slips in and out effortlessly. This was part of the re-rigging process. We don't think there was enough 'coast' once the motor stopped. The actuator still turns a few threads even the motor stops once the switch is hit, which allows for more pressure on the switch.