Originally Posted by
DaveReidUK
The 787 generates a synthetic airspeed value by combining inertial data and AoA, to substitute for UAS.
Whether you can do it the other way round, i.e. generate a synthetic AoA from IRS and IAS, isn't immediately obvious.
Given that AOA and pitch angles are slightly different ( within one or two degrees ? ) , and that Inertial data can output/measure pitch along with motion vectors and constantly comparing to two AOA sensors, I would guess that any sudden or major AOA change above a realistic amount would trip appropriate alarms etc.- thus the inertial system would be a basckup. And while a bit off topic- Boeing has been flying an orbital bird ( similar to space shuttle ) for months and then under full autocontrol brings it back for a ' normal' style aircraft landing. Obviously there are NO external AOA probes or probably no external pitot sensors. My guess/speculation is that they do it all with internal- inertial sensors...