C340 LANDS AT ARPT WITH RWY NOTAMED CLOSED.

Narrative

I WAS SCHEDULED TO FLY MY PAX; IN HIS ACFT; FROM FT WORTH; TX; TO SAN MARCUS; TX; FOR BUSINESS ON THE MORNING OF JUN/WED/03. AFTER RECEIVING MY SECOND WX BRIEFING OF THE MORNING; INCLUDING ALL RELEVANT NOTAMS; I FILED AN IFR FLT PLAN TO SAN MARCUS. AFTER WE BOARDED THE ACFT AND I WAS PREPARING TO PICK UP MY CLRNC FROM FT WORTH SPINKS CLRNC DELIVERY; MY PAX TOLD ME THAT WE HAD A CHANGE OF DEST TO BOERNE. I CALLED CLRNC DELIVERY AND INFORMED HIM OF THE CHANGE; IT WAS DULY MADE; MY CLRNC COPIED; AND WE WERE ON OUR WAY TO BOERNE. AFTER CANCELING THE FLT PLAN A FEW MI FROM THE BOERNE ARPT AND EXECUTING A VISUAL APCH; INCLUDING ALL PROPER RADIO XMISSIONS THROUGHOUT THE ENTIRE PATTERN WITH NO RESPONSE; I MADE AN UNEVENTFUL LNDG. WHILE ON MY ROLLOUT ABOUT MIDWAY DOWN THE RWY; I NOTICED A CESSNA WITH LNDG GEAR NOT EXTENDED AND SITTING ON ITS BELLY ON AN EXIT-WAY BTWN THE RWY AND THE TXWY. A CREW WAS IN THE PROCESS OF REMOVING THE CESSNA FROM ITS LOCATION. THE GEAR UP LNDG HAD OCCURRED THE EVENING BEFORE; PROMPTING THE ISSUANCE OF A LCL NOTAM. THE NOTAM APPARENTLY WAS STILL IN EFFECT WHEN I UNEXPECTEDLY HAD TO CHANGE MY DEST FROM SAN MARCUS TO BOERNE. SINCE I HAD ALREADY BEEN THROUGH THE PROCESS OF OBTAINING A BRIEFING AND LCL NOTAMS FOR SAN MARCUS; REQUESTING ADDITIONAL LCL NOTAMS SIMPLY DID NOT OCCUR TO ME. THIS OVERSIGHT WAS MY FAULT; BUT IT WAS ABSOLUTELY UNINTENTIONAL. I PRESUME THAT THE NATURE OF THE LCL NOTAM WAS ADVISING OF A CLOSED ARPT SINCE THERE WAS A DISABLED ACFT; AT THAT TIME; ON THE RWY. ALTHOUGH THE EVENT RESULTED IN NO PROB; AN FAA INSPECTOR INVESTIGATING THE GEAR UP INCIDENT DID INTERROGATE ME AND TOOK THE CUSTOMARY; OFFICIAL DATA AND INFO. I BELIEVE THAT THE CAUSE OF MY FAILURE TO OBTAIN LCL NOTAMS FOR THE NEW DEST WAS DUE TO MY MENTAL SATISFACTION OF ALREADY HAVING BEEN THROUGH A PROPER AND THOROUGH PREFLT BRIEFING PROCESS. I OFFER THIS ONLY AS A REASON; NOT AS AN EXCUSE. I FEEL THAT THE PREVENTION OF FUTURE SUCH SCENARIOS LIES IN GIVING CONCERTED THOUGHT TO THIS FACT: A CHANGE HAS OCCURRED IN MY FLT SIT. WHAT ADDITIONS OR OTHER MODIFICATIONS SHOULD OR MUST I CONSIDER OR MAKE?