Smythe, et al.
There was no need to change the basic MCAS algorithm. It was ‘tried and tested’, and certificated.
The safety issue involved the integrity of the AoA input to the computation, where an error resulted in unanticipated trim operation due to weaknesses in the implementation - design good, engineering and certification not so.
Tried and tested...certificated??? You are posting in jest, no? Such a simple fix, yet so far 87 days on the ground?
From 0.6 to 2.5 without notifying the FAA? What was tested? Test pilots dont appear to have tested 2.5?
What about the low speed stall, push the nose down 2.5 degrees at low speed, and presumably low altitudes?
High G issues? push the nose down 2.5 degrees on a high G manuever?
It is not that one of the AoA sensors failed, look at how they are wired. They are not coupled to a single source, each one is wired to different sources. That is a rewire, not just a software issue.
How do you explain the certification process with EASA and the FAA used MCAS at 0.6, and never revealed the 2.5 change to the regulators? The AoA light on disagree doesnt work? ooops. In reality, if 2 sensors disagree, well then, what, pick one you like? (while the ac is nosing down because it thinks its stalling...
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