I have no experience with aviation technology, but with TTE it should be possible to run Inflight Entertainment on the same network as the flight-control system.
Read the description !
TEthernet® (SAE AS6802) is a scalable, open real-time Ethernet platform used for safety-related applications primarily in transportation industries and industrial automation
TTEthernet-based solutions provide:
determinism
availability
safety
fault tolerance
security
hard real-time operation
synchronization
None of those are features you need for IFE systems. Its quite obvious from the manufacturers description what it's for !