MIL HELI NON ADHERENCE TO ATC CLRNC HAD LTSS FROM SMA TKOF ON OCCUPIED RWY. PLTDEV. SYS ERROR.

Narrative

I RECEIVED A 'TAXI INTO POS AND HOLD' CLRNC FROM THE TWR FOR RWY 2. WHILE I WAS HOLDING; TWR CLRED A MIL HELI TO TKOF FROM THE N END OF THE RWY. IMMEDIATELY AFTER THAT CLRNC WAS ISSUED; TWR CALLED ME; ADVISED ME THAT MY TFC WAS THE HELI; TO FOLLOW THAT TFC; AND THAT I WAS CLRED FOR TKOF. AT THIS POINT; THE HELI HAD NOT YET DEPARTED. I WAITED FOR THE HELI TO TAKE THE RWY. HE DID SO; LIFTED OFF; AND APPEARED TO BE DEPARTING SO I INITIATED MY TKOF ROLL. I WAS FLYING AN SMA SO MY TKOF ROLL WAS SHORT IN BOTH TIME AND DISTANCE. AT MY ROTATION POINT; IT BECAME APPARENT THE HELI WAS NOT DEPARTING BUT WAS CONTINUING TO HOVER OVER THE N END OF THE RWY. BY THE TIME I WENT THROUGH DISBELIEF AND WAS ABLE TO REACT; MY ACFT WAS AIRBORNE. AT THIS POINT; IT SEEMED SAFEST TO CONTINUE RATHER THAN ABORT. I INITIATED A R HAND TURN TO XWIND AND DEPARTED THE AREA. THE HELI WAS CONTINUALLY IN SIGHT. CLOSEST HORIZ APCH WAS APPROX 1200 FT WITH INCREASING VERT SEPARATION. ASSESSMENT: 1) I FEEL THE TWR SHOULD NOT HAVE ISSUED MY CLRNC UNTIL AFTER THE HELI WAS AIRBORNE AND DEPARTING. 2) HAVING OBSERVED; AS PIC; MANY SIMILAR HELI DEPS; I WAS PREDISPOSED TO BELIEVE THE HELI WAS GOING TO INITIATE DEP IMMEDIATELY AFTER LIFTOFF AS THEY ALWAYS SEEM TO DO.