To: Another KOS
The certification authorities never see the FMECA (Failure Mode Effects and Criticality Analysis) and if they want to see it they must request permission and look at it at the manufacturers' facilities. The FMECA is used to define the failures and their modes and effects of those failures with this information feeding into the Safety Hazards Analysis (SHA). The SHA defines the probabilities of occurrence for different types of failures from minor failures to catastrophic failures. It stands to reason that if you go down to the piece part failures as opposed to trying to define the failures at the component level the information feeding into the SHA will be more detailed and the SHA will be more accurate in predicting the probabilities of the failures and their effects at the airplane level.
Even with the detailed figures as opposed to the less accurate figure the end result is defined by the manipulation of the numbers to show a probability of catastrophic failure at 10 9 or better and it is pure crap.
