Most companies of LH size work extremely hard to ensure their networks have adequate diversity.
This often means literlaly going out and walking the paths of critical cables to ensure they reallyare seeprated when they enter your properties and not two cables in one duct.. All kinds of checking for common points of failure are routinely undertaken for mission critical enterprises .
Telecoms plant is often owned or used by more than one company and so buying from company A doesnt mean they use different networks from company B . In this case it is unthinkable that they serve sucha critical facility with just one cable . The reason I said the CEO should get the chop is because he has created or tolerated an obviously slack cunture and attude when it comes to resilience as IT is critical to all major airline ops.. He gets a big bonus when they make a lot of money but he does little or none of the work to do that himself. . In this case of course LH shouldnt run their own telcoms network but theyare a big enought company in Germnay to get T Systems and other suppliers to do exactly what they want .
This is big screw up so someonebig has to be resopnsible