Originally Posted by
ivor toolbox
Think they need to revisit part 25.671, then part 25.672, as a stability augmentation system must have "a warning which is clearly distinguishable to the pilot under expected flight conditions without requiring his attention must be provided for ANY failure in the stability augmentation system or in ANY OTHER AUTOMATIC OR POWER OPERATED SYSTEM WHICH COULD RESULT IN AN UNSAFE CONDITION IF THE PILOT WERE NOT AWARE OF THE FAILURE"
(caps inserted)
At base level this MCAS is just an augmentation system is it not?
In my view, it does not comply with the basic certification requirement above, and someone in Boeing knows this, software alone won't fix it.
Ttfn
I think you have pointed to the initial Kernel of causal factors. Many other posters have debated on the presumed application of System Safety "-1309" as the underlying certification base. However, if a more specific requirement is applied, as you suggest, then that regulation must take precedence over a less specific regulation.
I would be most interested on how the FAA's North East region found compliance and under what regulation as this is where the fundamental fault may lie.
I'm not ready to lay the complete fault at Boeing's door unless they misrepresented facts when submitting their application for acceptance. On the other hand how would the other world regulators accept a faulted certification base ?