Originally Posted by
wetbehindear
Once bitten, twice shy... or NOT?
We pointed earlier that Amsterdam and Lion Air accidents were in part due to single channel/sensor.
In fact on 31 July 2009, Boeing informed airlines about a future Service Bulletin that they are going to rectify the situation in regard to Amsterdam rad alt problem by a comparator function between the measured heights of the left and right radio altimeter systems.
https://books.google.com.tr/books?id...terdam&f=false
I will post related Service Bulletin when I find it.
P.S. related page 130 bottom part.
I wasn't thinking about the Amsterdam crash (which had a lot of other factors) but had a similar train of thought, given that a failed AoA sensor appears to cause serious trim issues, why not have a comparator between left and right AoA. If values are outside parameters, set trim to neutral, maintain AT (Reducing thrust will reduce nose up moment but pilots are familiar with this on 737) and climb which isn't perfect but seems to be a damn sight better than the current situation.