What was found
FLIGHT CONTROL, ON APPROACH, ENROUTE FLAPS FAILED TO EXTEND BEYOND FLAPS 5, USED ALTERNATE FLAP PROCEDURES TO EXTEND FLAPS TO 15. MAINTENANCE REMOVED AND REPLACED FLAP POSITION INDICATOR IAW T/C 1B27001, OPERATIONAL CHECK WAS GOOD. FUNCTIONAL TEST OF FLAP POSITION INDICATOR S/N 1594 CONFIRMED REASON FOR REMOVAL FINDING THE RT SYNCHRO INOPERATIVE, AND THE LT SYNCHRO SLUGGISH. REPLACED RT SYNCHRO, AND CLEANED AND LUBRICATED THE LT SYNCHRO BEARINGS IAW CMM 27-50-03.