TRINIDAD TB20 PLT HAS AN NMAC DEPARTING JYO.

Narrative

I ANNOUNCE MY DEP FROM RWY 17 AND START MY TKOF ROLL. JUST AS I ROTATE; I HEAR SOMEONE NEW CALL IN; 'LEESBURG TFC; LEESBURG TFC; FLT CHK...BLAH; BLAH; BLAH...' MY FIRST THOUGHT WAS THAT SOMEONE WAS ON THE APCH TO RWY 17; WHICH MEANT THEY WERE BEHIND ME; SO I DIDN'T GIVE IT MY FULL ATTN; HENCE THE 'BLAH; BLAH; BLAH.' DURING THE XMISSION; I CAUGHT THE '...VOR ALPHA...' AND WONDERED WHAT APCH THAT WAS. THE XMISSION ENDED WITH '...ANYONE IN THE AREA; PLEASE ADVISE; ANYONE IN THE AREA; PLEASE ADVISE!' THIS ANNOYED ME AS MY ASSUMPTION WAS THAT NO MONITORING OF THE CTAF HAD OCCURRED BEFORE BLOWING INTO A NON-TWRED ARPT SPACE. THE OTHER PLANES IN THE PATTERN GAVE POS RPTS; BUT I HAD JUST ROTATED; WAS ESTABLISHING MY CLB AND CLEANING UP THE AIRPLANE. I STILL ASSUMED THAT THE AIRPLANE WAS BEHIND ME; AND WHEN I WOULD EVENTUALLY GIVE MY XWIND RPT; THAT WOULD BE SUFFICIENT; BUT IT IS STILL NAGGING ME ABOUT THE VOR-A APCH. AT ABOUT 350 FT AGL; I RAISED MY TKOF FLAPS. MY HABIT IS TO LOOK AT THE FLAPS TO CONFIRM THEY'RE UP. AS I LOOKED OUT; A KING AIR PASSES BELOW ME 50-75 FT IN THE OPPOSITE DIRECTION. NOW IT CLICKS THAT THE VOR-A IS FOR RWY 35 OFF THE ARMEL VOR AT DULLES; AND I HAD JUST USED UP ONE OF MY LIVES. SHORTLY AFTER WE PASS; THE KING CALLS A MISS (HE'S PROBABLY BELOW THE MISSED APCH ALT). I FOUND OUT LATER THAT WHEN HE WENT BACK TO APCH; HIS ONLY COMMENT WAS THAT THERE WAS TOO MUCH TFC AT LEESBURG TO LAND. I DON'T KNOW IF HE EVER SAW ME.