The FAA has issued an AD to be effective November 3, 2020, for certain McCauley Propeller Systems governors produced between January 31, 2017, and September 27, 2018.
It was discovered that during that time period, an unapproved idler gear bearing was installed on some governors. The non-conforming part may cause failure of the idler gear bearing further causing an failure of the governor, loss of pitch control, engine and propeller overspeed, engine oil contamination, and loss of control.
The AD requires inspection of the governor and replacement of the idler gear bearing if it is found to be the non-conforming part. Non-conforming parts are marked with “BA 59.” If the part does not have this marking, no further action is required.