What was found
THE RT ENGINE THRUST REVERSER WILL NOT STOW. THE NOSE COWL ASSY (P/N 22850020-113), THE TORQUE BOX ASSY (P/N 22850200-140) AND THE SLIDER BLOCK ASSY (P/N 22850281-113) HAD EXTENSIVE DAMAGE. THE 10 O'CLOCK POSITION DRIVE ACTUATOR ASSY (P/N 3272570-6) FAILED AT THE CLEVIS ATTACH PIN. ALL COMPONENTS HAVE 561 HOURS TOTAL TIME SINCE NEW. PROBABLE CAUSE OF FAILURE IS TRACK BINDING AS ADDRESSED IN SERVICE BULLETIN A 601R-78-012. ALL DAMAGED COMPONENTS REPLACED.