Originally Posted by
Rananim
It trimmed the aircraft nose down in response to faulty AoA....the report from the previous commander clearly says "STS trimming the wrong way".
Originally Posted by
silverstrata
It didnt.It trimmed the aircraft nose down in response to faulty AoA....the report from the previous commander clearly says "STS trimming the wrong way".The pilots just have to recognize that......How do you know this is a genuine fault? The 737 STS system ALWAYS trims the wrong way - that is what it is ‘suposed’ to do. And the pilot response on every flight is to trim back the right way - which overrides the STS. Which is why the STS is widely cursed - it may be trimming into a ‘safer’ regime, but pilots like an aircraft to be in trim, not trimmed nose down - so it is still a pain when hand flying.
Silver
Not a Boeing driver, frequent lurker here, but:
From reading this thread and the Boeing alert, it seems that a big part of the issue is that the crew was not aware of MCAS. The writeup for STS "trimming the wrong way" may very well have been written by a captain that thoroughly understood STS and was aware of which way it should normally trim....but what he was seeing was the undocumented MCAS feature trimming opposite to the direction STS would be expected to trim in a given flight regime. The writeup mentioning STS may just be because this was the only feature of which he was aware that would cause the trim to run in manual flight.