Regarding those instruments with analog backup, e.g. N1/N2 on the 737NG. The analog signal is fed to the DEUs directly. Would the DEU be smart enough to recognise a missing N1/N2 sensors as a failure rather than zero rpms (and therefore show blank indications)?
The N1/N2 and accelerometor sensors also feed directly into the Airborne Vibration Monitoring Unit (AVM). I wonder how this reacts to open circuit sensors?
How catastropic is catastrophic? Both rotors locked? EEC power wiring destroyed? EGT harnesses damaged? Engine oil tank ruptured? Engine oil quantity wiring damaged?
Engine oil tank quantity goes directly to the DEUs. Again, is the DEU smart enough to recognise open circuit wiring Vs empty tank (and show blank for open circuit wiring)?
Perhaps we could have some Maintenance Engineer input here? With the cannon plug removed from an oil quantity sensor, what are the cockpit indications? The Maintenance Manual and FIM don't seem to offer any clues.