UNAUTH UNCOORD RWY OP AT A NON TWR ARPT.

Narrative

I DEPARTED FRM ON AN EVENING PLEASURE FLT WITH A FIRST- TIME PAX AND MY TEENAGE SON ON BOARD. UPON RETURNING TO FRM FOR LNDG; I HAD A SICK PAX IN THE BACK SEAT WHO ADVISED ME TO LAND AS SOON AS PRACTICAL. APCHING FRM I CALLED ON 122.8; MY POS AS '5 MI W; INBOUND; LNDG.' SUBSEQUENTLY; I CROSSED OVER THE VOR AND ENTERED A STANDARD L-HAND PATTERN; DOWNWIND FOR RWY 13. NO OTHER TFC WAS OBSERVED IN THE PATTERN. I AGAIN ADVISED 'DOWNWIND FOR RWY 13' AND PROCEEDED ON A NORMAL APCH FOR LNDG. MY FINAL ADVISORY CALL WAS 'TURNING FINAL FOR RWY 13; FAIRMONT.' AFTER LNDG; I IMMEDIATELY EXECUTED A 180 DEG TURN; ON THE RWY TO EXIT VIA THE NEAREST TXWY. AFTER EXECUTING THIS TURN; I OBSERVED ACFT LIGHTS FROM THE LCL COMMUTER ALSO APCHING FOR A LNDG. HE PWRED UP AND DID A GAR. WHILE TAXING TO THE HANGAR; I DETERMINED THE CAUSE OF THE RADIO 'PROB' AND CALLED THE BEECH 1900. I ADVISED HIM; 'I DID NOT HEAR ANY OTHER TFC IN THE AREA BECAUSE MY RECEIVER WASN'T WORKING.' I THEN APOLOGIZED FOR NOT CLRING THE RWY SOON ENOUGH FOR HIM TO LAND. MY SPECIFIC WORDS WERE; 'I ALWAYS YIELD TO THE AIRLINER.' HE RESPONDED; 'THAT'S OK; I NEEDED THE GAR PRACTICE ANYWAY.' AFTER PARKING THE ACFT; I CHKED AND DOUBLE-CHKED THE INTERCOM BOX; WIRING CONNECTIONS; ETC; AND FOUND EVERYTHING IN WORKING ORDER. I CAN ONLY SURMISE THE VOLUME WAS INADVERTENTLY TURNED TOO LOW FOR ME TO HEAR OTHER TFC. A LCL PLT RPTED MY RADIO XMISSIONS SOUNDED 'REAL MUFFLED' SO SOMETHING WAS XMITTING. I DID NOT EXIT THE RWY TO THE SIDE BECAUSE OF THE EXTENSIVE RAINFALL WHICH MADE THE AREA BTWN THE RWY AND TXWY TOO SOGGY TO USE. I ALSO FELT TURNING AROUND AGAIN (ANOTHER 180 DEGS) TURN AND FAST TAXIING TO THE NEXT EXIT WOULD NOT HAVE PROVIDED SUFFICIENT CLRNC FOR THE BEECH TO LAND EITHER. I HAVE NOW ADDED 'CHK RADIOS' TO MY PRELNDG CHKLIST. I DOUBT IF I WILL EVER AGAIN TRY TO LAND-SHORT TO EXIT VIA THE TXWY CLOSEST TO THE HANGARS. IT WAS THIS HASTE; COUPLED WITH THE SICK PAX; AND THE QUIET RADIO WHICH CAUSED THE COMMUTER TO 'GAR' IN THE FIRST PLACE.