What was found
PHX - EMERGENCY LANDING - FLT 0628 - EN ROUTE FROM OAK TO PHX AT 33,000 FT A-SYSTEM HYDRAULIC QUANTITY INDICATOR WAS ERRATIC INDICATING BETWEEN A HALF QT AND FULL. DECLARED EMERGENCY INTO PHX. AFTER LANDING HYDRAULIC QUANTITY INDICATION RETURNED TO NORMAL. MAINTENANCE REMOVED AND REPLACED A-SYSTEM HYDRAULIC QUANTITY TRANSMITTER IAW T/C R4R29001, INDICATOR STILL READING INCORRECT, REPLACED QUANTITY INDICATOR AND SYSTEM CHECKED GOOD. VENDORS FUNCTIONAL TEST OF INDICATOR S/N B01114 CONFIRMED FAILURE OF UNIT. TEARDOWN OF UNIT FOUND HEAVY CONTAMINATION, LAMPS INOPERATIVE CAUSING UNEVEN ILLUMINATION, AND A DAMAGED FILL TUBE. REPLACED LAMPS (P/N 328) AND FILL TUBE, UNIT WAS CLEANED, CALIBRATED AND TESTED IAW CMM 29