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Avionics Products gear actuator on M20J ‘78


dominikos

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Spent Saturday morning reading through airframe/engine logs of my new M20J ‘78. Reading an article in September issue of Mooney Flyer about actuator spring put a fear of God in me and I wanted to see whether any maintenance was performed on mine. And looks like I have an original Avionics Products gear actuator(s?) with 2,154 hours. Last annual was in 7/20, so I still have sometime to go but decided that this is probably something I should address urgently for a peace of mind.

Any thoughts, experience with those actuators? Am I looking at overhaul, replacement? what would you guys recommend?

Appreciate any thoughts, pointers and feedback.

- Dominik

 

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Dominik,

What did the Mooney Flyer say about it?

See if my guess is what you are thinking...

1) Something about a spring...

2) There is a ‘no back clutch’ spring...

3) It has a lifetime of many thousands of hours...

4) It has a Recommended  TBO (exchange for new)around 1k hrs...

5) It had a bad history of poor manufacturing... (since solved)

6) If the darn thing breaks... the gear doesn’t work...
 

7) the spring develops surface cracks over its lifetime...

8) cracks tend to propagate...

So... if that is it... consider getting the old one swapped out with a new one...  :)  it’s not an emergency...

PP thoughts only...

Best regards,

-a-

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I hope that I’m not going to misrepresent it. There is a ‘no back’ clutch spring that if it gives up, it will prevent gear from extending, either normal or manual. Did a bit more digging since then and discussed with AP who said it makes sense to replace with next manual but did not feel it was required to be done immediately.. So, will not practice emergency gear extensions til annual.

here is the link - https://themooneyflyer.com/issues/2020-SepTMF.pdf, p12.

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On 10/24/2020 at 12:42 PM, dominikos said:

Any thoughts, experience with those actuators? Am I looking at overhaul, replacement? what would you guys recommend?

I know about as much as you do about this (basically I posted a link to the same article here a month or so ago :))... But I believe that there are no currently-manufactured actuators for the J model. If you actually need a new one, they show up from time to time on ebay for 8 or 9 grand. But you can have them rebuilt by a reputable shop for more like 1. I think that Lasar does these. 

The spring itself can be hard to find, but several people have mentioned this already to @Jonnyand I believe it's on his radar screen for new parts availability. 

MS has great history on the no-back spring. @Hyett6420has an article somewhere here with a zillion photos. @donkaye has a similar article on his blog. 

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4 hours ago, dominikos said:

I hope that I’m not going to misrepresent it. There is a ‘no back’ clutch spring that if it gives up, it will prevent gear from extending, either normal or manual. Did a bit more digging since then and discussed with AP who said it makes sense to replace with next manual but did not feel it was required to be done immediately.. So, will not practice emergency gear extensions til annual.

here is the link - https://themooneyflyer.com/issues/2020-SepTMF.pdf, p12.

Practicing manual gear extension is good once early on...

Doing it up on jacks is a great time to do it...

It probably gets done at each annual...
 

There may be a dozen modes of failure... but wearing out an electric motor probably isn’t one of them...  how much time would the motor get?  10 seconds per flight... 20 minutes each year?

There may be a way to run a search on how many of these springs have actually broken and disabled the landing gear...

Your memory would have to be really good... to be able to point out the accident... without doing a search...
 

Best regards,

-a-

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