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Why is this: “once this thing pitches up, it wants to keep pitching up”? And why is it more of an issue with the engines in their new position? Thanks.

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Couple of things here to keep in mind. First, when the A320 came out I wrote extensively about its fly by wire system, which was highly controversial at the time (early 1990s). It’s been nearly thirty years since then and long story short, Airbus has vastly more experience with implementing cockpit automation than Boeing. Boeing simply got in far over their expertise with deadly results

Second, Airbus’ 320 airframe does not impose the same issues with larger engines that the 737 does. For starters, the 330 airframe started life in the era of large high-bypass turbofans — its initisl engines were much larger than the 737’s initisl engines

It wants to keep pitching up because the engine cowlings are now far ahead of both the center of gravity and the center of lift. And the cowlings generate significant lift themselves. Aerodynamically they act as levers that pull the nose up and the higher the angle of attack, the more they pull. That is dynamic instability and as I point out you want to have ejection seats in any dynamically unstable aircraft (ir fighter jets)

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