Grease incompatability

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Zombie Master
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Grease incompatability

Post by Zombie Master » Mon Apr 16, 2018 7:14 pm

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richard t
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Re: Grease incompatability

Post by richard t » Mon Apr 16, 2018 10:54 pm

seal leaking, red grease is good in flange bearings, white grease wtf was he thinking

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Ken in Oklahoma
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Re: Grease incompatability

Post by Ken in Oklahoma » Wed Apr 18, 2018 11:39 am

richard t wrote:
Mon Apr 16, 2018 10:54 pm
seal leaking, red grease is good in flange bearings, white grease wtf was he thinking
I'm guessing he was thinking grease is grease. Hit don't matter none.

Ken
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Wobbly
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Re: Grease incompatability

Post by Wobbly » Tue May 01, 2018 11:19 pm

Read this... https://en.wikipedia.org/wiki/Alaska_Ai ... Flight_261

The problem was the grease was changed. Either grease alone would have worked fine, but not mixed. The resulting corrosive effects of the mixed grease ate up the ball screw, which locked the control surfaces.
After 20 years as a professional bike mechanic and 30 years as an engineer I know just enough to be dangerous !

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Steve in Golden
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Re: Grease incompatability

Post by Steve in Golden » Wed May 02, 2018 1:05 am

Wobbly wrote:
Tue May 01, 2018 11:19 pm
Read this... https://en.wikipedia.org/wiki/Alaska_Ai ... Flight_261

The problem was the grease was changed. Either grease alone would have worked fine, but not mixed. The resulting corrosive effects of the mixed grease ate up the ball screw, which locked the control surfaces.
The NTSB didn't seem to think it was the change in grease, but rather not enough grease.
Over the course of the investigation, the NTSB considered a number of potential reasons for the substantial amount of deterioration of the nut threads on the acme screw, including the substitution by Alaska Airlines (with the approval of the aircraft manufacturer McDonnell Douglas) of Aeroshell 33 grease instead of the previously approved lubricant, Mobilgrease 28. The use of Aeroshell 33 was found not to be a factor in this accident.[1] Insufficient lubrication of the components was also considered as a reason for the wear. Examination of the jackscrew and acme nut revealed that no effective lubrication was present on these components at the time of the accident.[11] Ultimately, the lack of lubrication and resultant excessive wear of the acme nut threads were determined to be the direct causes of the accident.[1]

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Zombie Master
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Re: Grease incompatability

Post by Zombie Master » Wed May 02, 2018 1:57 am

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