Did the aircraft have the Speed Trim System?
Haven't seen any discussion about that, but I would think it would apply.
Originally Posted by SmartCockpit B737NG
Speed Trim System
The speed trim system (STS) is a speed stability augmentation system designed to
improve flight characteristics during operations with a low gross weight, aft center
of gravity and high thrust when the autopilot is not engaged. The purpose of the
STS is to return the airplane to a trimmed speed by commanding the stabilizer in
a direction opposite the speed change. The STS monitors inputs of stabilizer
position, thrust lever position, airspeed and vertical speed and then trims the
stabilizer using the autopilot stabilizer trim. As the airplane speed increases or
decreases from the trimmed speed, the stabilizer is commanded in the direction to
return the airplane to the trimmed speed. This increases control column forces to
force the airplane to return to the trimmed speed. As the airplane returns to the
trimmed speed, the STS commanded stabilizer movement is removed.
STS operates most frequently during takeoffs, climb and go-arounds. Conditions
for speed trim operation are listed below:
• Airspeed between 100 KIAS and • Autopilot not engaged
Mach 0.5
• Sensing of trim requirement
• 10 seconds after takeoff
• 5 seconds following release of
trim switches
Offering this for consideration of possible failure modes.