I think Boeing is probably facing a potentially bigger issue than the failure of the MCAS system. The bigger issue is that it is becoming increasingly apparent that the FAA failed to provide adequate oversight of delegated certification functions. What Boeing really needs to fear (apart from the punitive damages from the lawsuits) is that the airplane will have to undergo a complete re-certification. And even if senior FAA officials are satisfied, I am not sure that other world authorities, especially the European JAA are going to take the FAA's word on it this time.