What was found
DURING APPROACH TO KMEM, WITH AUTOPILOT ENGAGED AND AIRCRAFT FULLY CONFIGURED, AIRPLANE BEGAN A SIGNIFICANT RHYTHMIC PULSING WITH CORRESPONDING YOKE MOVEMENT. WENT AROUND TO TROUBLESHOOT & PULSING STOPPED. FULLY CONFIGURED EARLY WITH NO PULSING. PASSING 1200' ON SECOND APPCH SHORTLY AFTER DUAL LAND ENGAGED, PULSING BEGAN AGAIN. CLICKED OFF AUTOPILOT & PULSING STOPPED. PULSING LASTED APPROX 30 SEC BEFORE INITIAL GO AROUND & ONLY 1 SEC BEFORE WE DISCONNECTED A/P ON 2ND APPCH. EMERGENCY DECLARED AFTER 1ST GO AROUND. R&R OF IB LT ACTUATOR.