Quote:
Originally Posted by
mabuhay_2000 
It seems utter madness to have the aircraft's flight computers on the same network was the PAX WiFi.
Aircraft don't use the internet for navigation or communication. Some aircraft have internet capability for passenger entertainment only.
I believe the point being made is that connecting non-flight critical systems to the same common communications network is a bad idea. Once such a system is connected to an aircraft data bus, it becomes possible to jam the bus with traffic that disrupts flight critical communications. This can be done in any number of ways and has been an issue in telecomms (we called it "the babbling bus problem" back in the 1960s), RF comms ("being stepped on", jamming, interference), and the internet (DOS (Denial of Service) attacks, SYN flooding, etc.). One can design ways to address these issues but it adds complexity and is difficult to test, as you must prove nothing bad can possible happen.
Reduced to the absurd, it is the same as connecting the highways at an airport to the runways with paved roads and trusting the planes and cars to play nicely - what could go wrong?