Narrative:

We were cleared for takeoff runway 31L. ATC made no mention of helicopter traffic crossing the runway downfield overhead, nor did we hear tower talking to the helicopter. After liftoff both the nfp and myself spotted helicopter Y almost directly ahead passing right to left. I had to lower the nose in order to fly under its flight path and we passed directly below it. If I had maintained the normal pitch attitude for takeoff it definitely would've resulted in a collision. The helicopter didn't appear to take a corrective action, nor did its pilot say anything over the tower frequency. The nfp on our flight was also PIC and chose not to tell the tower anything either. I'm sure that the tower had cleared this helicopter to maintain visibility sep with us as it crossed the airport to land on the south ramp, but we must have been on ground frequency at the time. The helicopter pilot then misjudged our likely takeoff path, thinking our airplane would take longer than it did to lift off. If only the tower had alerted us to the traffic, we could've been prepared for it. Instead the tower entrusted the whole operation to the faulty judgement of the helicopter pilot and we nearly collided.

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Original NASA ASRS Text

Title: NMAC BETWEEN DEPARTING COMMUTER AND GA-HELI OVERFLYING RWY.

Narrative: WE WERE CLRED FOR TKOF RWY 31L. ATC MADE NO MENTION OF HELI TFC XING THE RWY DOWNFIELD OVERHEAD, NOR DID WE HEAR TWR TALKING TO THE HELI. AFTER LIFTOFF BOTH THE NFP AND MYSELF SPOTTED HELI Y ALMOST DIRECTLY AHEAD PASSING RIGHT TO LEFT. I HAD TO LOWER THE NOSE IN ORDER TO FLY UNDER ITS FLT PATH AND WE PASSED DIRECTLY BELOW IT. IF I HAD MAINTAINED THE NORMAL PITCH ATTITUDE FOR TKOF IT DEFINITELY WOULD'VE RESULTED IN A COLLISION. THE HELI DIDN'T APPEAR TO TAKE A CORRECTIVE ACTION, NOR DID ITS PLT SAY ANYTHING OVER THE TWR FREQ. THE NFP ON OUR FLT WAS ALSO PIC AND CHOSE NOT TO TELL THE TWR ANYTHING EITHER. I'M SURE THAT THE TWR HAD CLRED THIS HELI TO MAINTAIN VIS SEP WITH US AS IT CROSSED THE ARPT TO LAND ON THE S RAMP, BUT WE MUST HAVE BEEN ON GND FREQ AT THE TIME. THE HELI PLT THEN MISJUDGED OUR LIKELY TKOF PATH, THINKING OUR AIRPLANE WOULD TAKE LONGER THAN IT DID TO LIFT OFF. IF ONLY THE TWR HAD ALERTED US TO THE TFC, WE COULD'VE BEEN PREPARED FOR IT. INSTEAD THE TWR ENTRUSTED THE WHOLE OPERATION TO THE FAULTY JUDGEMENT OF THE HELI PLT AND WE NEARLY COLLIDED.

Data retrieved from NASA's ASRS site as of August 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.