Experts....
How susceptible are ADIRUs to extreme turbulence? Specifically, the attitude section.
I seem to recall an incident with one of our aircraft (Boeing) which lost two of the three IRUs due to severe turbulence (perhaps about 10 years ago). I can't recall, however, if the IRUs were switched to ATT mode to help recover basic attitude displays.
Do ADIRUs have more than the basic 3 laser gyro and accelerometer pairs?
Do A320s automatically switch to an attitude display if navigation mode is lost? (plus manual backup). Of course, ATT mode is mode is useless if you can't achieve level flight for a certain period of time.
Note: I've even seen faulty attitude displays on ISFDs (with solid state accelerometers) after a manually generated upset. A reset was required.
There's a lot of talk about using pitch/power when air data is lost, but if attitude was lost, too....