Re:Boeing 737 Max: Automated Crashes [video]
by cjbprime on Monday December 30, 2019 @04:22PM
(#21916823)
Yeah, and I think MCAS ended up fully deflecting the stabilizer on Ethiopian. Even with a somewhat more reasonable altitude, I wonder how long it takes to physically manually retrim from one end of the jackscrew to level flight. I think even the electric motor takes at least six seconds to do that.
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Re:Boeing 737 Max: Automated Crashes [video]
by _ph_ on Monday December 30, 2019 @04:41PM
(#21916954)
From what I read the situation was made worse by the fact that they where flying a bit on the fast side even when they were not going down yet, increasing the load on the stabilizer.
Re:Boeing 737 Max: Automated Crashes [video]
by secabeen on Monday December 30, 2019 @05:19PM
(#21917165)
A bit of the fast side is an understatement. They were at full takeoff power the entire time they were fighting the trim. They never reduced engine power, which would have reduced the forces on the stabilizer. An easy thing to miss certainly, and it was one of many factors that contributed to the crash:
https://nymag.com/intelligencer/2019/04/what-passengers-expe...
Re:Boeing 737 Max: Automated Crashes [video]
by cjbprime on Monday December 30, 2019 @05:55PM
(#21917440)
A possible ameliorating factor: they had an IAS Disagree warning (unreliable airspeed) since takeoff, and it may be policy to keep airspeed up in that case -- not knowing your airspeed means that reducing it may cause a stall.
(Still, they could have asked ATC for an speed reading or used other measurements to convince themselves that it was safe to slow down.)