Originally Posted by
lomapaseo
Vulnerability is not a failure condition.
if it were lots of military aircraft would never fly.
In my view currently flying aircraft come under "continued Airworthiness" standards which take into account in-service experience including maintenance
The issue at hand with the max is its original certification basis and whether the data used was valid..
The FAA written policy and practice for decades in managing continued operational safety has been that a potential single failure (such as a wire bundle fault condition), unless that failure can be agreed to be effectively impossible, does not meet the fail safe standard intended to be applied to nearly all aspects of transport airplane systems design, and warrants corrective action. (There are a few specific exceptions to this standard due to practicality issues - turbine engine rotor failures for example.) I posted a link to the applicable policy above. The FAA has issued numerous airworthiness directives to address potentially catastrophic failure conditions resulting from a single failure even when that condition, or the initiating single failure, is not known to have already occurred in service. That was the basis for my comment on the stab wiring of both the Max and the NG.