There are multiple networks on an airplane. Some are air gapped, but running multiple parallel wiring systems adds a lot of weight to a plane. If a medium and l

There are multiple networks on an airplane. Some are air gapped, but running multiple parallel wiring systems adds a lot of weight to a plane. If a medium and low security system can share some cabling and be secured through software, then there is little reason not to. The engine control wasn't hooked up to the AV system or anything!