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Gear collapse at Paine field - Everyone ok

ChrisV

By ChrisV
in General Mooney Talk

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carusoam Grand Master

carusoam

Posted
Posted

Then...

Proper procedure is your best friend, no?

Down and locked...

It is really a two step procedure.

 

There should be no fear...

Knowledge is power...

Probably helps to be a mechanical engineer or machinist or mechanic while being involved with your annual inspections.... :)

 

Otherwise there is a lot of trust placed in your mechanic... make sure you have a good one.

PP thoughts only, not a ME, machinist, or mechanic...

I’m still looking in the pic for where the Mooney is...

 

Best regards,

-a-

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aviatoreb Grand Master

aviatoreb

Posted
Posted

Once about a dozen years ago, my friend at my home airport had a gear collapse when I was watching him land.  Gear were down, it rolled a moment until all the weight came down on it then boom it collapsed and screeched to a quick stop.  In an M20C.  It was "totaled" by insurance because of the hull value, but then later we saw it selling again in airworthy condition from a repo business.

E

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Andy95W Grand Master

Andy95W

Posted
Posted
1 hour ago, mike_elliott said:

Worn down lock block? 

Paul can tell the story better, but in the case of his old M20C, the new owner took it for an annual inspection and the new shop felt the need to completely re-rig the landing gear.  It failed shortly thereafter. 

Rigging is obviously important, but many still don't quite get the narrow window that the gear has to be rigged.  Too loose, and the over-centers won't hold and the gear will collapse.  Too tight, on the other hand, and components will break, usually at the welds at the gear themselves.  The Johnson Bar can produce a surprising amount of force due to the long lever arm, and old welds are no match for it.  The ease of movement and locking of a properly rigged Johnson Bar is surprisingly light. 

A lot of people have been mentioning the down lock block here lately, but I would be surprised if even 5% of gear failures were due to wear at that point.  And the latch on the down block will still work even with a severely worn out block.  Additionally, the original Johnson Bar Mooneys didn't even have a latch- but pilot error led to its creation.

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gsxrpilot Grand Master

gsxrpilot

Posted
Posted
2 hours ago, mike_elliott said:

Worn down lock block? 

 

46 minutes ago, Andy95W said:

Paul can tell the story better, but in the case of his old M20C, the new owner took it for an annual inspection and the new shop felt the need to completely re-rig the landing gear.  It failed shortly thereafter. 

Rigging is obviously important, but many still don't quite get the narrow window that the gear has to be rigged.  Too loose, and the over-centers won't hold and the gear will collapse.  Too tight, on the other hand, and components will break, usually at the welds at the gear themselves.  The Johnson Bar can produce a surprising amount of force due to the long lever arm, and old welds are no match for it.  The ease of movement and locking of a properly rigged Johnson Bar is surprisingly light. 

A lot of people have been mentioning the down lock block here lately, but I would be surprised if even 5% of gear failures were due to wear at that point.  And the latch on the down block will still work even with a severely worn out block.  Additionally, the original Johnson Bar Mooneys didn't even have a latch- but pilot error led to its creation.

Yeah @Andy95W tells it pretty well. The shop that did the annual and reset the, according to them, out of spec over-centers, obviously wouldn't admit to anything. Once the insurance company showed up, no one would talk for fear of getting stuck with the bill. 

I'd bet a tank of 100LL that they mis-rigged the over-centers. Laura at SWTA had checked them every 100 hours for me as long as I owned the plane. I obviously never had a problem. Then the new owner takes it in for annual and the shop, not a Mooney shop or MSC, says the gear is rigged wrong and changes it. A few flight hours later, it's sitting on it's belly with the gear collapsed.

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StevenL757 Grand Master

StevenL757

Posted
Posted
On 12/30/2019 at 11:08 AM, gsxrpilot said:

Properly set pre-load on the gear makes this virtually impossible. 

I know the MSC that I work with for maintenance, not only knows how to check and set the pre-load properly, but also understands the consequences of not setting it correctly. 

Absolutely.  Same with my IA.  

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