A B737-800 ON APCH AT 1500 FT MADE GAR; DECLARED EMER DUE TO TRAILING EDGE FLAPS STUCK AT 2 UNITS WITH 15 UNITS SELECTED. FLAPS EXTENDED IN ALTERNATE MODE.

Narrative

ON ILS FINAL APCH IN ZZZ WX WAS 600 FT OVCST; 5 MI IN LIGHT RAIN. COPLT WAS FLYING AND HAD JUST STARTED CONFIGURING FOR LNDG. WITH THE FLAPS AT 2; HE CALLED FOR GEAR DOWN AND FLAPS 15. AT THIS POINT WE NOTICED THE FLAPS STUCK AT 2 WITH THE HANDLE AT 15. WE TRIED RESETTING THE HANDLE BACK TO 2 AND THEN TO 15; BUT THE FLAPS STAYED AT 2. WE WERE AT APPROX 1500 FT AT THIS POINT AND I DIRECTED THE COPLT TO GO AROUND. WHILE WE WERE GOING AROUND AND I WAS PULLING OUT THE CHKLIST; I DIRECTED THE COPLT TO DECLARE AN EMER BASED ON THE POSSIBILITY OF LNDG AT FLAPS 2 ON A WET RWY. WE RAN THE CHKLIST AND WERE ABLE TO GET THE FLAPS EXTENDED TO 15 WITH ALTERNATE EXTENSION. FROM THIS POINT WE LANDED WITHOUT INCIDENT AND TAXIED TO THE GATE. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE FO WAS FLYING AND THE TRAILING EDGE FLAPS STUCK AT 2. HAD SELECTED 15. ORDERED GAR AND DECLARED AN EMER DUE TO WET RWY AND POSSIBILITY OF LNDG AT FLAPS 2. THE ALTERNATE EXTENSION WAS PERFORMED AND FLAPS EXTENDED TO 15. LANDED UNEVENTFULLY. MAINT HAS NOT RELEASED ANY INFO ON THE MAINT ACTION TAKEN OR THE FAILED COMPONENT.