What was found
AIRCRAFT YAWS TO LEFT IN-FLIGHT AND VEERS LEFT ON GROUND. FOUND LEFT RUDDER BOOST CONTROL SOLENOID FAILED IN OPEN POSITION ALLOWING BLEED AIR TO THE BOOST ACTUATOR. REGARDLESS OF RUDDER BOOST SWITCH ON OR OFF, RIGHT RUDDER BOOST SOLENOID PREVIOUSLY HAD SAME PROBLEM. TOTAL TIME, 2,066.1 HOURS. SUSPECT CAUSE - MOISTURE CONTAMINATION. SUBMITTER STATES TO MAKE SURE, PN 101-524009-91, RUDDER BOOST AIR FILTER IS INSTALLED. FILTER HAS A MOISTURE DRAIN BEECH SERVICE COMMUNIQUE, NR 60 REFERENCES THIS.