I've read an re-read the posts on this thread as well as EASA AD No. 2019-0171 and now believe I have a basic understanding of the situation. My understanding (such as it is) is thus:
- The A321neo has bit of a pitch instability problem in certain narrow portions of its flight operating envelope. This problem could possibly be due to the larger nacelles of the new engines shifting the center of lift forward at high angles of attack.
- The earlier, ELAC101 apparently deals with the pitch problem per Station Zero's Post #11.
- The ELAC102 does not automatically handle the potential pitch up problem as is the case with other Airbus control laws; however, the sidestick can be moved manually to counter the pitch up problem (Preemo's Post #17).
- Since modification of the software to more closely follow existing Airbus control laws will cure the problem, it is as Station Zero stated in his Post #19, ultimately a software problem.
I can't help but compare the A321neo situation to that of the B737MAX. The initial pitch instability problem was similar in both aircraft, but the two manufacturers, A and B, dealt with the problem differently. Due to Airbus' extensive experience with FBW and it's related automation, their system was far superior to the Boeing MCAS, which relied on a single sensor and could not be easily/intuitively overridden by the flight crew. Well, anyway, that's my take on the situation. Am I close?
Cheers,
Grog