#1291
MAX’s Return Delayed by FAA Reevaluation of 737 Safety Procedures
Hello John, good to hear from you on the topic. Indeed, the media appears to be convinced that MCAS is a "stall prevention system" that uses the HS to push the nose down at high AoA's.
I agree with you on "longitudinal static stability". I believe the issue was the relative lightness (pull, in pounds) on the control column as the MAX approached high AoAs vs. in comparison with the forces that obtained for the earlier NGs undergoing the same testing, that indicated an NG certificiation compliance matter, and raised the question regarding "same NG type certificate". I believe the certification required a higher force to signal to the pilot the approach to the stall - enter MCAS.
That "lightness" was apparently due to the additional lift from the larger engine nacelles, attended by the slightly more forward-of-CofG mounting. It is reasonable to think that the slightly higher thrust line due pod-clearance issues would slightly reduce the nose-up effect of more-forward engines, within that very narrow (or rare), band of high-AoA & flight conditions.
I may be missing bits and I certainly don't wish to sound "engineer-ish" about this in any manner! - way above my pay grade and training - this is just my recollection from an early reading of some of those web articles.