[conspire] Added carrier scrutiny

[Rick Moen]

Quoting Ross Bernheim (rossbernheim at gmail.com):

> Some reports now are fingering the auto-pilot system, not the stall
> recovery system.  Engaging the auto-pilot disconnects the stall
> recovery system. The crashes of the planes in question seem to have
> occurred after the auto-pilot was turned on.

I'd be able to comment with greater confidence if you had provided a
link/links or identified your source(s).  My initial assessment is 
that you've either misread something or it was a story filtered via
a reporter what was a bit too far outside his/her field of expertise.

Back in November after the Lion Air disaster, FAA issued an emergency
airworthiness directive for the 737 MAX 8 and 737 MAX 9[1], which, if
these search URLs are persistent, you can read here:
http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgad.nsf/0/83ec7f95f3e5bfbd8625833e0070a070/$FILE/2018-23-51_Emergency.pdf

It highlighted the syndrome found in the Lion Air disaster where the AoA
(angle of attack) sensor was sending erroneous angle data to the flight
control computer's new Maneuvering Characteristics Augmentation System 
(MCAS) circuitry that is the new component in all 737 MAX craft, that
tries to prevent stalls by forcing nose-down trim when it thinks
necessary.  You will note (page 4) that the revision to operating
procedure says that, if this happens again, the pilots should (a)
disengage autopilot (to makes sure the pilots can assert attitude
apply trim control using the control column and regular trim controls)
and, if runaway trim override continues, set the stabilizer trim ('STAB
TRIM') switches to the 'CUTOUT' position (aka 'STAB TRIM CUTOUT').  The 
latter switch position directly disables MCAS.

The relationship between the MCAS and the autopilot is almost
incidental.  This site clarifies further:
https://www.satcom.guru/2018/11/737-mcas-failure-is-option.html

  Manual trim command would pause MCAS for five seconds; then it would
  pick up again.

  The Autopilot Trim Cutout switch would turn off the MCAS trim command.

  The Stabilizer Trim Cutout switch would remove power from the trim
  motor.

  The flight crew have the option to grab the stabilizer trim wheel as a
  brute-force method.

  Reports indicate that MCAS was added to the 737MAX as a result of issues
  with accelerated stalls.  These are already abrupt.  The handling
  characteristics deteriorated are reported to be attributed to the engine
  changes unique to the MAX. 

What I read on on a couple of apparently well informed sites yesterday
is that, because Boeing had to move the engines a bit to create the two 
MAX designs, plus the effect of the lengthened fuselage (see footnote),
the default airframe handling characteristics became a bit off, i.e., it
tends to go nose-up a bit in situations where the regular 7373 did not,
so MCAS got added to autodetect the situations in question and force
downwards trim.  Boeing's best guess immediately after the Lion Air
disaster is that the main problem was that the angle of attack sensor
malfunctioned and was a single point of failure, so they proposed to mae
the MCAS inputs be a bit gentler and add additional sensors so a single
malfunctioning AoA sensor would no longer be a SPoF.

There have been claims that work at FAA examining the problem and
proposed solutions _would_ have proceeded more rapidly except for the 
recent 45-day government shutdown that The Toddler insisted on.  Top FAA
officials recently denied this claim, and, well, it's already been
established that current top management's claims must be taken under
advisement.


[1] 737 MAX 8 and 9 are both modification to the original 737 design
with longer fuselages, the 9 being longer of the two.  All discussion of 
'737 MAX 8' recently also applies to the MAX 9, and both types have now
been grounded.