Aging Eton Gear Actuator

[Chewka]

Hello again folks,

Another issue we are facing on our 81 M20J during a very painful annual inspection is an aging gear actuator.  Our AME did a closer inspection after hearing a rachetting sound coming from the actuator during the gear swing.  Upon closer inspection they found that the jackscrew has play in it, part of the emergency system is damaged and other integral parts are showing wear.  

 

 

There was an instance about 4 years ago that passengers of mine had accidentally dislodged the safety on the emergency gear handle.  No one touched the handle itself but when I went to retract the gear on takeoff, the actuator circuit breaker popped ie) the motor wouldn't run because the emergency gear safety was dislodged.  Not knowing what had caused this at the time, I returned to land and we had our then AME inspect it.  He just reset the system, swung the gear and said we were good to go.  Since the circuit breaker popped right away, I am hoping it did it's job to protect the actuator by keeping the motor from running (this appeared to be the case).  Is dislodging the safety on the emergency gear handle then selecting gear up, causing the circuit breaker to pop enough to have caused damage to this system or is it likely that 30-some years of operation has just taken it's toll?  I believe it's the original unit actuator which would be about 33 yrs old with about 2500 hrs on it.  

 

You can't see a whole lot except for some metal filings but I have attached a few photos from this inspection.   

 

Thanks again guys!  Looking forward to your input.

 

Brenden

Calgary, AB

[co2bruce]

Check with a MSC, I think these are replaced on a time schedule. I know mine was on the Eagle. Might be 1000 hours.

[ArtVandelay]

Check with a MSC, I think these are replaced on a time schedule. I know mine was on the Eagle. Might be 1000 hours.

I just had mine rebuilt, it was past TBO, the emergency mechanism broke, SB M20-282A back spring installed, motor overhauled.

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[mike_elliott]

There is no TBO on the actuator, just a 1,000 hour SB that is of dubious merit on it's no back clutch spring. 2,500 hours is nothing. Mine has over 10,000 hours on it. The chattering can be caused by improper shimming, but the metal filings indicate that this is now something more. Attempting to retract the gear with the emergency gear actuator pull handle unlatched in and of itself didn't cause this problem. Perhaps one of the true Mooney maintenance experts here will eventually chime in. Unfortunately that group does not include me. You might want to find one to fix it. Good luck!

 

I understand Tom Roush to be the Gear actuator Jedi of the Guru group

[Chewka]

Turns out it is a Vickers NOT an Eaton.  The first picture I attached is actually of the emergency gear mechanism.  Our AME thinks that by unlatching the safety and then attempting to operate the gear this could have caused damage to the mating parts before the circuit breaker popped.  I don't completely understand how the safety engages / disengages the gear from the actuator and motor assembly but am hoping some exploded view drawings from the maintenance manual will clear it up.  We are sending it into LASAR for an overhaul.  

[Chewka]

Sounds like the chattering, play in the jackscrew and the wear of other internals is just wear and tear.  I am hoping they can do a good job of the rebuild.  I hear they are the go-to shop for this.  

[Chewka]

Photos from previous year

[Chewka]

Pics and exploded view

Actuator - exploded view.pdf

[KSMooniac]

Sounds like a good course of action and that you are in good hands. Thanks for the follow up.

Jim

This!

 

If the emergency gear system is mis-rigged, it is possible that it can get damaged with normal operation and then fail to work when needed.  Consider yourself lucky to have discovered it now, and not when your gear motor failed and left your wheels stuck up in the wells.  LASAR should be able to get you fixed up nicely, and you'll need to triple-check the emergency system rigging when you re-install it.