Originally Posted by
OldnGrounded
Take a look at the Satcom Guru post jimjim1 cited and at the
AAIB bulletin linked there.
If you meant to say the dashpot loads up the drive gear so the dash pot might make the drive gear slip, that's a good point, but the dash pot load is proportional to rate, so it would produce a slightly varying error in the reported AoA in a random-walk kind of way. The Lion Air unit had a solid offset and the ET302 unit had a sudden change without noteworthy dynamics at the time.
The AAIB bulletin also notes that of two AoA sensors one was not assembled correctly, as opposed to coming loose, and the other had a persistent electrical problem blamed on a tiny particle in one of the pick ups that gave a glitch at a certain orientation. There's something to be said for idiot proofing assemblies, but it seems like there is no consistent history of AoA sensors with internal parts coming loose. More concerning, from the report, is they had placed a previously removed electrically deficient sensor back on the plane without finding the original defect it was removed for. I'm surprised they did not send it back to the manufacturer for diagnosis, but I'm not surprised they did not understand how to diagnose it correctly. A continuity meter and a quick turn is not sufficient.
The solution, if it was a problem, would be a drop of shaft-locking material. Henkel makes several grades. It would not get an item number on a diagram, but be included in the same instructions as define the acceptable required torque.
What does a 737 Max sensor look like inside, years later?