BOEING 737-800NG FLIGHT CONTROLS REVIEW PART 1 

Hi Robson, thank you for your very interesting question about this system. I'm pretty sure you're reading in deep the 737 manuals. First of all, it is interesting you're mentioning the Wheel to Rudder Interconnect System (WTRIS). As you probably know, the only aircraft manual that shows something about it is the MEL (for both NG and MAX). Q:During a turn, is the yaw damper that assists the pilot by applying the required amount of rudder deflection? A: FCOM VOL 2, it says: During normal operations, main Yaw Damper ASSISTS in turn coordination ( dutch roll prevention and gust damping as well ). In Manual reversion flight, the Standby Yaw Damper assumes movement of the control wheels abd sends signal to the standby rudder PCU to move the rudder. Rudder input from the yaw damper DOES NOT back drive the rudder pedals. Q: in a non normal situation, with loss of either/both hydraulic power, does the WTRIS kick in and take over this function? A: WTRIS only activates during loss of BOTH hyd systems A and B. During Manual reversion, both FLT CONTROL switches are moved to STBY RUD. The Yaw Damper switch can be set to ON when the Stby hydraulic system powers the stby yaw damper. SMYD2 commands rudder movement for the WTRIS, stby yaw damping and turn coordination. During the Standby yaw damping operation, the WTRIS commands a small amount of rudder movement as a function of the control wheel aileron input to help assists turns during flight control manual reversion operations. I hope this will help you with your questions Robson. Have a great day.

@@AviatorLifeCS Captain, yes, helped a lot. These nuances of jet flying make a life of a curious person more challenging in search of answers. Thank you for your time.

@@robsonbr1246 I'm happy it helped Robson! We are always learning.