LNAV VNAV,
Much as above except I understood that the computation is in the ADC; thus AoA is used in the ADC for pressure error correction; if each AoA feeds it ‘own side’ ADC then the ADCs speed computations differ and alert the crew, similarly for Alt Disagree.
Also, if AoA is in error, so too the computation for low speed awareness (AoA to speed relationship) on the speed scale; this may / may not contribute to the ‘IAS disagree’ alert.
Ian W, the ADCs could be responsible for the AoA disagree (or fly guidance comp); however the alert is an optional installation, normally associated with the optional AoA dial display on EFIS. Which in this instance would be meaningless because there is no way to determine which AoA value is correct, whereas for IAS and ALT there is a third system to crosscheck.
Thus although the Lion maintenance electronic log flagged AoA amongst other problems, the crew’s report concentrated on the indications of unreliable airspeed and stick shake.