B737 rudder actuator - current situation?

Date:         18 Mar 97 03:14:54 
From:         m.fiddler@staffs.ac.uk (Martin Fiddler)
Organization: Staffs University, UK
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What's the current situation regarding the PH rudder actuators
on the B737?  Sticking valve sleeves are possibly suspected of alledgedly
causing rudder hard-overs, maybe contributing to a couple of
unsolved crashes due to sudden roll on final approach.  I'm not sure
if anything approaching proof of the hardovers has ever been found.

Last I heard: pilots were being trained to use assymmetric thrust
as well as full ailerons to control an uncommanded roll, a kickback
test was regularly being done using the rudder pedals (on the ground,
and a redesigned rudder actuator was on the way.

Have any recommendations been made about hyd. fluid cleanliness?
What about auto-land, where the autopilot hasn't authority to
counteract a sudden roll.  Are these done with more ready-ness than
usual to take manual control?

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