Originally Posted by
MurphyWasRight
Not sure why a common AoA failure cause is needed, in any case there are very significant differences between the 2.
Lion Air :Incorrect (offset) values present for entire (2!) flights, the offset shows as soon as speed is sufficient.
Not sure of aerodynamics but doubt that a damaged vane would have a consistent offset.
Since this was a refurbished unit it is possible that it was mis-assembled or damaged on installation/test, only other possibility is a wiring issue, which might fit with prior unit being intermittently bad. One can be sure the investigators will be looking at this in depth.
Ethiopian: Values ok at first then a sudden and dramatic shift to full over and at the same time the heater circuit opens.
This can be explained by bird strike or prior (ramp rash) damage.
Recovery of either unit intact enough for analysis is unlikely due to high energy of crashes and position of sensors.
Finding the missing vane is also unlikely due to small size and other factors, an all out search might find it but would at most just confirm one of the 2 causes, prior damage or bird strike.
If the rwy was closed after the accident and if someone then bothered to examine it for FOD after the event, it is unlikely any feathers will turn up along with the missing AoA vane.