To: Chin Chin
As a consultant, I supervised the preparation of the FMEAs. My main function in preparing the FMEAs was on the dynamic system and the power train. However I did not work on the front gear box.
The individual that worked on the front gear box identified several potential problems relating to circuitry defects and internal leakage both of which would cause the application of the rotor brake in flight. Jacking that failure up a notch or two it was apparent that they were catastrophic failures. In my investigation of the potential problems I determined that it was possible for the brake to come on hard and as a result the two thin walled drive shafts would be severely damaged enough to separate losing all of the services on the front gear box as well as causing a significant overheat condition. Those catastrophic failures among all of the others were eliminated from the FMEAs on the whim of the department manager.
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The Cat