What was found
CREW REPORTED, STARTED DESCENT INTO PHX MANAGED. STARTED DOWN AND REVERSED STARTED CLIMBING AT 2,800 FT. TRIED V/S DIDN'T HELP. A/P OFF. TRIED TO LOWER NOSE AND COULDN'T. PULLED POWER BACK, GOT DOWN AFTER REVERSED CLIMB. HAND FLEW FOR APPROXIMATELY 5 MINUTES. TRIED A/P AND A/T AND THEY WORKED REMAINDER FOR FLIGHT. A/C CLIMBED 900 FT BEFORE WE COULD STOP. MAINTENANCE WAS UNABLE TO DUPLICATE ON GROUND. PERFORMED ELAC TEST PER 27-93-00-701-001 AND SEC TEST PER 27-94-00-701-001/002A. NO DISCREPANCIES NOTED DURING EITHER TEST. REPLACED NR 1 FMGC PER 22-83-34. C/W AUTOLAND TEST 22-97-00. ALSO, PER ENGINEERING AND MOC REQUEST, BOTH FAC'S WERE REPLACED PER 22-66-34. TEST FLIGHT SATISFACTORY.