PPRuNe Forums - View Single Post - MAX’s Return Delayed by FAA Reevaluation of 737 Safety Procedures
Old 29th Sep 2019, 17:55
  #2717 (permalink)  
jdawg
 
Join Date: Feb 2015
Location: usa
Age: 37
Posts: 41
Likes: 0
Received 0 Likes on 0 Posts
Originally Posted by Takwis
The Stabilizer Trim System (STS ... onto which MCAS was grafted) wanders against my commands, and every 737 pilot's commands, every single takeoff. Multiple times. As the aircraft accelerates to flaps up speed, the STS is, not continually, but periodically, trimming nose up to maintain the speed it was previously trimmed for. Every single takeoff generates multiple STS trims, in the opposite direction to that desired by the pilot. When the trim moves, driven by the STS, the pilot trims in the opposite direction...habitually.

When the trim moves nose down "by itself", the pilots will naturally respond by trimming nose up. Probably barely noticing it. It looks just like the STS they work against every single takeoff... because it IS the STS...except that it is moving in the opposite direction. So much so, that the surviving crew wrote it up that way. It does NOT look like the stab trim runaway we were (once, long ago) trained for. Boeing could not have masked the problem any more effectively if they had tried.

If I "perform[ed] a trim runaway memory item once pitch starts wandering against [my] commands", I would do so every single flight.

I'll do it tomorrow, just for the heck of it.
So you're saying it would take a lot longer than 3 seconds to differentiate between a true runaway trim VS MCAS activation VS normal STS operation on takeoff. Good, we agree. And now we are to determine which of those three conditions are the cause. Wow. What a mess.
Now add to that stick shaker and eventually an overspeed warning in your ears and unreliable air speeds on the screens in front of you. I'm sure you're starting to get the picture that this is not simply pilot error.
The Max was an aircraft built around it's engines. That was what the Wright Brothers and other early 20th century aircraft designers did. Boeing is just doing it in 2019.
Time to call this aircraft a new type of you ask me. Do it right. Not one more life should be lost.
jdawg is offline