PPRuNe Forums - View Single Post - Ethiopian airliner down in Africa
View Single Post
Old 19th Mar 2019, 16:38
  #2067 (permalink)  
Ian W
 
Join Date: Dec 2006
Location: Florida and wherever my laptop is
Posts: 1,350
Likes: 0
Received 0 Likes on 0 Posts
Originally Posted by LDRA
STS always asserts unwanted trim input by design.

Is there any cockpit indication of what system(STS, Mach, MCAS) is actually commanding trim movement? If not, how does one reliably tell it is from MCAS?
The reliable indication is that it is always nose down trim and unless you do something about it and the AoA is still indicating a close to stall value it will wind in another nose down trim. Unsurprisingly, this will require more back stick pressure, If you trim against it then after 5 seconds it will wind in more nose down trim. If your 'driver assist' in your smart car was repeatedly trying to pull you out of your lane - how many times would it take before you switched it off? IF nose down trim repeatedly runs making the control column force difficult to handle and you also know that this is a fault that can happen in the MAX and has caused fatal crashes, would you
(a). Say it's not runaway trim as that is running continuously to the maximum position so I'll just carry on pulling harder, or,
(b) Say the trim is repeatedly doing something I think is dangerous I will set the Stab Trim cut out switches to Off as was said in that AD ..
Ian W is offline