Originally Posted by
derjodel
I think nobody at Lion Air at the time had any clue about the existence of MCAS. It seemed like "just a bad AoA vane" and the airplane response made no sense. Whoever signed it off could not have put 2 and 2 together with the information they had...
From post #2141 that does not appear to be the case as the jump seat rider on the previous flight knew and apparently told the crew how to fix it having gone back into the cabin and retrieved a manual.
As anyone who has delivered systems with User Guides, User Manuals, Technical Support Manuals will know - these documents become 'shelfware'. It seems that even AD's fall into that category now.
