LTT COMMUTER CREW AND C172 HAD AN NMAC AT SBA WHEN THE C172 PLT TOOK OFF WITHOUT CLRNC.

Narrative

WHILE LNDG ON RWY 25 AT SBA WE EXECUTED A GAR TO AVOID A COLLISION WITH A C172 TAKING OFF ON RWY 15. WE WERE CLRED TO LAND AND WERE IN THE FLAIR WHEN WE HEARD THE TWR CTLR SAY; 'CESSNA SO AND SO; STOP.' THE FO AND JUMP SEAT RIDER BOTH ACQUIRED THE CESSNA VISUALLY. AS PF; I INITIATED A GAR AS SOON AS 'GO AROUND' WAS STATED. I THEN ACQUIRED THE CESSNA VISUALLY MOMENTARILY AS IT WAS ON ITS TKOF ROLL TO OUR R AND FRONT. THE FO STATED THAT HE FOLLOWED THE CESSNA VISUALLY AS IT WENT BENEATH US. AS A CREW WE ALL AGREED THAT WE MISSED THE CESSNA OVER THE INTXN OF THE RWYS BY APPROX 300 FT VERTLY AND THAT HAD WE NOT EXECUTED A GAR WE WOULD HAVE COLLIDED. WE LANDED WITHOUT FURTHER INCIDENT. LATER; WHILE SPEAKING BY PHONE; THE TWR STATED THAT THE CESSNA WAS CLRED 'INTO POS AND HOLD' ONLY. THE GAR WAS EVASIVE; BUT NOT AGGRESSIVE IN NATURE. THE GAR WAS SOMEWHAT UNUSUAL IN THAT WE WERE IN THE FINAL STAGES OF THE LNDG FLAIR JUST PRIOR TO TOUCHDOWN WHEN WE EXECUTED THE GAR. THIS INCIDENT CALLS QUESTION TO THE VALIDITY OF THE 'POS AND HOLD' CLRNC WHEN USED ON INTERSECTING RWYS. ALSO; IN THIS CASE THE EXTRA SET OF EYES THAT THE JUMP SEAT RIDER BROUGHT TO THE CREW UNDERSCORED A POSITIVE REASON FOR ALLOWING A JUMP SEAT RIDER.