Desert Rat wrote: ↑
16 Mar 2019, 15:25
I don't understand how Boeing's chief engineering office has validated this envelope protection system with only 2 AOA sensor's relying on one input to validate exceedance.
At contrario, Airbus is using three sensors which required correlation between two of them to validate inputs to Flight control computers and envelope protection activation.
Big difference in concept and redundancy.
That should never have passed CAA checks.
Good point. I've wondered the same.
But I think they got away with it because the 737 classic/NG/MAX s are developements of an older type and type cetificate. As long as you are developing from an existing TC, not all the latest requirements apply like it would if you are developing a new aircraft.
For instance, the ATR42, DHC8 and F50, tree competitors, were all developed in the 80's. The ATR and Dash had elevator and aileron disconnect systems incorporated, because the requirements of the day mandated them for newly developed aircraft. The Fokker did not, as it was developed from the F27 Type Certificate.
My guess is that something similar applies here. Nevertheless, I agree that Boeing could have, and probably should have upgraded on their own initiative… Probably already with the NG...