$$$ M20J Landing Gear Clutch Spring $$$

[mulro767]

It weighs less than 1/2 of an ounce.  It's a spring with a 3/4" diameter and maybe a 1/2" wide.  It's costs $800 for the part and takes 2-3 hours of labor to replace?  There's an AD on it to replace every 1000 hours?  Failure of this spring renders your electric and alternate gear extension useless.  The Mooney part has been on back order. And I'm just hearing about this now!

 

Ok, I feel like an idiot.  Anyone have this spring fail?  Anyone replace it recently?  Anyone else feel like an idiot?

[29-0363]

I agree, the price is way over what it would cost to make. I believe the SB was issued after a just one spring failed in the late 90's and the airplane landed gear up.

 

The weak point in the spring is where they bend the 90 degree tangs on each end to retain it in place. You'll only need to replace the spring if it breaks, but here's a catch. When it does break, the undercarriage stops at whatever point in the extend/retract cycle the spring has failed, and one more sobering point I'll add, the manual extension needs an intact unbroken spring to operate - broken spring = manual extension disabled.

 

 

Good luck!

[jetdriven]

I'm with Jim, and also Don Maxwell. There was a defective batch of springs which triggered the SB. If they dont break in 1000 hours, they won't.  And another thing, if they aren't available, why fret?   This is one good thing about the 1977 M20J and the earlier planes, no back spring.  The downside is the 250 hour actuator gear inspection, which parts are not available for, either.

[fantom]

It's not a safety of flight AD; just a legal liability CYA SB. The only idiotic aspect is getting needlessly worked up about it.

 

Nobody is touching my no back clutch spring....ever!

[Bob_Belville]

Hum, another item to include in the selling points of my old E: No 1 AMU spring to replace.   

[OR75]

I'm with Jim, and also Don Maxwell. There was a defective batch of springs which triggered the SB. If they dont break in 1000 hours, they won't.  And another thing, if they aren't available, why fret?   This is one good thing about the 1977 M20J and the earlier planes, no back spring.  The downside is the 250 hour actuator gear inspection, which parts are not available for, either.

what 250h inspection on the actuator on the 77' are you referring to ? i am not sure i caught that.

[jetdriven]

Its SB M20-190B.  Recommend to inspect the 40:1 gears in the actuator every 200 hours.

[yvesg]

Can someone post a picture of that spring? Must be made of gold or titanium right?

Yves

[OR75]

you can look for the SB in the MAC website

[preinke]

Here is a picture of the gears on a 1977 M20J (3500 hours) . The coupling and both cables were replaced this year .

[Rich]

While I, too think it is an excessively expensive purchase, it is probably wise (from an insurance standpoint) to seriously consider this maintenance. After I had mine replaced in a 201 I once owned, the gears rattled (increasing the likelihood of a spring breaking) and it had t be "tweaked". When to old one came out, it looked just like to new one replacing it. But, I don't suppose that you will get any indication of a pending failure. I am told that If it fails, the gear will not move.

[AndyFromCB]

I would not touch and replace this part is yours is working. One of the mooneys I was looking at before I got my Bravo was an Eagle 310hp that had to land gear up right after the spring was replaced because it failed on first flight. This is one of those if it ain't broke, don't fix it.

[flyboy0681]

As an aside, I read that Carroll Ann Garrett had a no back clutch spring failure during one of her around-the-world flights. It must have failed when the gear was down, though, because it did not result in a gear up. Does anyone have details?

 

 

I attended Carol Ann's visit to our monthly Mooney Luncheon last February and she talked about it. During the question and answer period I asked her about the reliability of her plane ('92 J) and she said she only had one problem during her entire around the world trip, and that was the clutch spring. She said it failed in Kuala Lumpur after takeoff and she flew to Bali and then onto Perth, Australia to be serviced but was able to somehow extend it manually. She remarked that they were the worst flights she ever encountered because she had to apply constant rudder pressure for the entire trip and the speeds were slow. The trip to Bali took over 10 hours (Monroy tanks) and then 14 hours to the MSC in Perth. She commented that she was physically spent and couldn't fly for several days after.

 

Here is a photo of the partial retraction set against the Petronas Towers.

 

http://www.earthrounders.com/cgi/kuala_lumpur.php

[flyboy0681]

Great pic! Thanks for that and for the rest of the story. I wonder, though, if it was actually some problem other than the no back clutch spring that she encountered with her landing gear? Everything that I have read indicates that a no back clutch spring failure results in the gear being frozen in whatever position it was in when it failed. If that were the case here she would have by necessity have had to belly it in when she landed, which was apparently not the case?

Jim

 

 

Now that I think about it, she mentioned the clutch spring because she carried an extra one with her as a spare. But thinking back to the conversation, I believe she said the actuator failed and a new one needed to be flown to Perth from Texas. My apologies.