Machinery Lubrication

Machinery Lubrication November-December 2018

Machinery Lubrication magazine published by Noria Corporation

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Page 28 of 74

In January 2000, a tragic event occurred off the coast of California. Alaska Airlines Flight 261 was fl ying to San Francisco from Puerto Vallarta, Mexico. When the pilots realized the unexpected response from their fl ight controls, they fi rst attempted to troubleshoot out at sea to minimize the risk to people on the ground. In the terrifying last moments, the pilots tried heroically to fl y the plane upside down after the uncontrollable horizontal stabilizer had caused the plane to invert. All aboard were lost. e investigation began with the recovery of the wreckage, including retrieval of the horizontal stabilizer from the ocean fl oor. Incredibly, the investigation team was able to recover grease from the stabilizer jackscrew for analysis. e grease analysis, along with inspection of the jackscrew threads, revealed that the stabilizer control had been completely lost as the threads stripped away. e root cause was determined to be inade- quate lubrication of the threads and deferred maintenance inspections, which included measuring wear on the threads. Among the issues discussed in the investigation was a change in the grease used in the jackscrew. Over the history of operating these planes, the manufacturer presented an a lternate product as being approved for use, but there was no documentation of any compat- ibility testing between the previous grease and the new one. While not a contributing factor in the failure of Flight 261, the investigation suggested that product changeovers could create the condition of mixed lubricants if the previous product was not completely removed, and that this should be a concern for future maintenance activities. Most lubrication actions are not life-or-death decisions, but the same sort of damage that led to this tragedy is seen on a daily basis in grease-lubricated components around the world. e result of their failure can be unexpected downtime, higher maintenance costs or even personnel safety risks. In the worst cases, human lives may be at stake. It is time to stop treating grease as some simple substance that just needs to be pumped into machines at some random frequency and then hoping for the best. Machine greasing must be a systematic and carefully planned process to ensure safe operation of assets and to achieve maximum equipment life. W hether your asset mission 7 Steps to Trouble-free Grease Lubrication 24 | November - December 2018 | www . GREASES Rich Wurzbach | MRG Labs "Machine greasing must be a systematic and carefully planned process to ensure safe operation of assets and to achieve maximum equipment life."

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