Possibly of greater interest than comparing FAG bearing spalling with SNR bearing spalling statistics over the same period, is to compare the information in 1.6.11.4 with that in 1.6.11.5. Excluding the crash items, between 2001-2016, 27 bearings have been removed in service due to spalling or micro-pitting but (according to Airbus) only 2 of those were between 2009 and 2016.
FAG stated (in 1.6.8.3) that there have been no differences to the design or manufacture during the production life of their bearings, yet for the first 8 years 25 bearings (incl. both types) were removed (average 3.125p.a.) and for the next 7 years only 2 were removed (0.286 p.a.), despite any heightened concerns or vigilance there may have been following the REDL crash in 2009. I can’t quite figure that reduction of 91% out.
What, if anything, has changed materially in that time and in particular perhaps in, or shortly before, 2009? Was there any change to lubricants, additives or to internal spray nozzle arrangements?