Any one can explain why an erroneous AoA input can cause an IAS disagreement? Aren’t the inputs to the airspeed indicators just the static and pitot pressures?
There are a couple of aspects to this I believe:
- The AOA is used as part of Static Source Error Correction (SSEC) calculations, basically to compensate the fact that the pitot tube isn't usually aligned exactly with the airstream.
- Since there is a relationship between AOA and IAS, the AOA can be used as a "cross check" to detect pitot/static problems (blocked ports, etc.) . So a malfunctioning AOA could erroneously show up as an IAS issue.