Boxerworks.com

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

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.

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]