Originally Posted by
skidooman
Of course not ALL the systems are level A. Things like the flight management system, brakes, etc, the stuff that must absolutely not fail, that is level A. The rest have lesser requirements and not the triple redundancy.
These are bad examples of DAL A systems, because they're not DAL A systems.
FMS is generally level C, or maybe level B sometimes, but certainly not level A as it does not meet the requirement for severity of failure
conditions ("Failure conditions that would prevent continued safe flight and landing" for Catastrophic requiring level A). Similarly, braking systems are level B.