Originally Posted by
patplan
The MX in CGK didn't suspect the newly replaced vane to be the caused.
This multiple and varied mix of fault reports (all ADIRU related) suggests the problems are nothing to do with a faulty AoA sensor, but a problem within the ADIRU. Perhaps something like a erratic reference voltage to the A to D converter affecting several channels. The AoA sensor was replaced possibly just as a hopeful guess. The assumption then seems to have been jumped on that as the MCAS uses AoA, the errant behaviour of MCAS must have been due to an AoA fault. Possibly the ADIRU fault is 'confusing' the MCAS; perhaps it cannot handle AoA values that are all over the place and gets trapped in a logic loop. Can I ask a question of the many experts on this forum, are the ADIRUs, the displays and MCAS (FCCs) all on the same ARINC bus?