LGT PUT INTO HOLD FOR 15 MINS; THEN TOLD IT WILL BE AN HR. DECLARED FUEL EMER AND LANDED.

Narrative

ARRIVING IN SJO AREA WE WERE INFORMED BY SJO APCH TO PROCEED TO THE VOR AND TO HOLD. WE WERE IN DSCNT TO 16000 FT. WE WERE CLRED TO 12000 FT AND ENTERED HOLDING. WE WERE TOLD TO HOLD FOR 15 MINS AND WHEN WE ASKED FOR EFC WE WERE TOLD TO STANDBY. AFTER IN HOLD WE WERE TOLD THAT ARPT WAS CLOSED FOR BOMB THREAT AND WOULD REOPEN IN 1 HR. FMC SHOWED '0' HOLD TIME AVAILABLE WHEN I UPDATED HOLDING ALT. I INFORMED CAPT OF THIS. THE CAPT WAS BUSY WITH DISPATCH. WE THEN CONFIRMED SJO WAS CLOSED AND PREPARED TO DIVERT. THE CAPT EVALUATED FUEL STATE ENRTE WX AND DECIDED THAT SAFEST COURSE OF ACTION WAS TO LAND AT SJO. WE DECLARED EMER AND PERFORMED UNEVENTFUL LNDG AT SJO. SUPPLEMENTAL INFO FROM ACN 281021: REQUEST FOR EFC GOT ATC TO SAY 15 MINS THEN CHANGED TO 1 HR AFTER WE ENTERED HOLDING PATTERN. ACFT WAS NOW AT 12000 FT WITH 13000 LBS OF FUEL. I CONSIDERED OPTIONS OF GOING TO ALTERNATE OR HOLDING LONGER. ALSO CONSIDERED ACFT POS; OVER PERFECTLY GOOD ARPT; AND WX AT SJO. THEN I CONSIDERED THE TSTMS AND OTHER WX CONDITIONS ENRTE TO ANY OTHER ALTERNATE. I DECIDED THAT THE SAFEST COURSE OF ACTION WOULD BE TO DECLARE A FUEL EMER.