ACFT BE1900D HAD JUST UNDERGONE MAINT TO THE R ENG COWLING. CAPT TAXIED THE ACFT FROM MAINT; WALKAROUND HAD BEEN COMPLETED; TO THE MAIN RAMP WHERE FUELED AND CHKED AGAIN. 1 PAX BOARDED AND DEPARTED. AT CRUISE 10000 FT R ENG FAILED. AFT COWL LOOSE. DECLARED EMER AND RETURNED TO JAX. WX BELOW MINIMUMS AND MADE GAR DIVERTING TO CRG. LAND OK.

Narrative

THE FLT ORIGINATED IN JAX AND WAS BOUND FOR MCC. THE ACFT; A BEECH 1900D WAS IN JAX OVERNIGHT FOR MAINT. I WAS ASSISTED IN THE COCKPIT BY FO. 1 PAX WAS ABOARD. THE ACFT HAD UNDERGONE MAINT TO THE R ENG COWLING. THE FO PERFORMED A PREFLT IN THE HANGAR; THEN WENT OVER TO THE TERMINAL. THE CAPT STAYED AT THE HANGAR UNTIL THE ACFT WAS RELEASED FROM MAINT. THE CAPT THEN PERFORMED A PREFLT; WHICH WAS SATISFACTORY. THEN THE CAPT PERFORMED A RUN-UP CHK; COMPLETING ALL FIRST FLT OF THE DAY ITEMS. THIS CHK WAS ALSO SATISFACTORY. THE ACFT WAS TAXIED TO THE GATE BY THE CAPT. THE ACFT WAS FUELED FOR THE FLT. THE CAPT 'WALKED AROUND' THE ACFT AGAIN. THE PAX WAS BOARDED. A ROUTINE TKOF FROM RWY 13 WAS ACCOMPLISHED. CLBOUT AND DEP WERE BOTH NORMAL. THE FLT WAS RADAR VECTORED TO DIRECT OMN VOR AND CLBED TO 10000 FT. THE CLB AND CRUISE CHKLISTS WERE COMPLETED. WITHIN 5 MINS OF ENTERING CRUISE FLT WE FELT A YAW; THAT WOULD BE ASSOCIATED WITH AN ENG FAILURE. I ASKED THE FO TO LOOK OUT HIS WINDOW TO SEE IF HE COULD SEE ANYTHING. HE RPTED THAT THE R ENG COWLING (THE BACK HALF OF IT) HAD COME LOOSE AND WAS NO LONGER ATTACHED. THE CREW THEN DETERMINED THAT THE R ENG HAD FAILED. WE THEN COMPLETED THE PROPER EMER PROCS/CHKLISTS; TO ACCOMPLISH A PRECAUTIONARY SHUTDOWN OF THE R ENG. THE CREW THEN DECIDED TOGETHER TO DECLARE AN EMER AND REQUEST PRIORITY HANDLING BACK TO JAX. WE EXECUTED AN ILS RWY 7 APCH AT JAX AND MISSED THE APCH DUE TO A FOG BANK THAT HAD JUST FORMED AT THE ARPT. WE THEN FLEW TO THE NEXT CLOSEST ARPT; CRAIG FIELD; AND EXECUTED AN ILS RWY 3 APCH WHICH ALLOWED US AN UNEVENTFUL SINGLE-ENG LNDG. THE WX CONDITIONS WERE: WIND-CALM; VISIBILITY-3/4 MI; MIST; CLR; 22 DEGS/22 DEGS; ALTIMETER-30.09; ILS RWY 32 IN USE. THE RWY CONDITION WAS BARE AND DRY. THERE WAS NO DAMAGE TO PROPERTY. THERE WAS NO DAMAGE TO THE ACFT. NO ONE WAS INJURED. I'M NOT SURE HOW THE PROB AROSE. I HAVE FEW CONTRIBUTING FACTORS. I FEEL MY DECISIONS WERE SOUND; AND MY ACTIONS WERE REASONABLE. SUPPLEMENTAL INFO FROM ACN 344810: WE HAD A PARTIAL ENG FAILURE ON THE R ENG AND PERFORMED THE ENG FIM/FAILURE CHKLIST AND SINCE WE WERE NOT GETTING ANY THRUST FROM THE ENG WE DECIDED TO SHUT IT DOWN. DURING THE EMER CHKLIST; I VISUALLY CHKED THE ENG AND NOTICED THE TOP FORWARD COWLING HAD PARTIALLY SEPARATED.