On Sunday, September 22, 2019 at 9:27:40 AM UTC-5, Jim Wilkins
Post by Jim Wilkins Post by David E. Powell
With a shrinking western military personnel base during the
Post-Cold War period, could this have caused problems for the
Less base of experienced pilots transitioning to the airlines?
The airlines in some parts of the world are of course a mixed bag....
Apparently it has been known for many years that, under some
it can be very difficult or impossible for human strength to move the
horizontal stabilizer on the Boeing 737 manually. Following the recent
crashes there has been talk of requiring 737 pilots to have some specific
Would it be possible to extend the crank handles to provide more leverage?
One comment suggested a ratchet lever, like a socket wrench. I can see
it flying loose during the violent maneuvers that necessitated using
it, or crushing a hand against the enlarged control panel that
required Boeing to shrink the trim wheel.
Forcing the jammed stabilizer trim screw drive was the immediate,
though not the underlying, cause of this MD-83 crash:
"Acme" is the name of the thread profile, which is optimized for high
strength and long wear life. My metal lathe uses steel Acme-thread
drive screws with replaceable bronze nuts to move the cutting bit.
I'm glad I wasn't responsible for the safety engineering of the
complex equipment whose development I participated in, such as the
Segway and other electric vehicles, and aircraft electronics. I backed
out of medical electronics a few times because of the risks.