Narrative:

Departing hayden, co, scheduled 121 flight. Made all position reports on CTAF 123.0 (pushback, taxi, departing). Advanced thrust, started takeoff roll and accelerated quickly due to relatively light gross weight. Suddenly, a GA twin engine aircraft pulled out onto the runway. I could hear unicom broadcast to the GA aircraft that we had just announced our departure. We had not yet reached decision speed, I asked the captain what he wanted to do, thinking to myself that, if we aborted at this point, we would likely face 1 of 2 scenarios: collision or departure from the runway. I felt we had enough room to safely accelerate and become airborne over the traffic. Captain agreed with my thoughts and said, 'keep going.' we lifted off safely. The aircraft had already quickly exited the runway by this time. No further evasive action was needed or taken. Due to runway slope, it was not possible to see aircraft on ramp or midfield taxiway from takeoff point on runway. I think the probable cause of this incident was failure of GA aircraft to monitor the CTAF and to announce his intentions/movements, and be aware of ours. It would have been helpful if unicom (CTAF) could have seen this possible conflict and alerted us.

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Original NASA ASRS Text

Title: RWY INCURSION BY LIGHT TWIN CREATES A POTENTIAL CONFLICT NMAC WITH DEPARTING TFC.

Narrative: DEPARTING HAYDEN, CO, SCHEDULED 121 FLT. MADE ALL POS RPTS ON CTAF 123.0 (PUSHBACK, TAXI, DEPARTING). ADVANCED THRUST, STARTED TKOF ROLL AND ACCELERATED QUICKLY DUE TO RELATIVELY LIGHT GROSS WT. SUDDENLY, A GA TWIN ENG ACFT PULLED OUT ONTO THE RWY. I COULD HEAR UNICOM BROADCAST TO THE GA ACFT THAT WE HAD JUST ANNOUNCED OUR DEP. WE HAD NOT YET REACHED DECISION SPD, I ASKED THE CAPT WHAT HE WANTED TO DO, THINKING TO MYSELF THAT, IF WE ABORTED AT THIS POINT, WE WOULD LIKELY FACE 1 OF 2 SCENARIOS: COLLISION OR DEP FROM THE RWY. I FELT WE HAD ENOUGH ROOM TO SAFELY ACCELERATE AND BECOME AIRBORNE OVER THE TFC. CAPT AGREED WITH MY THOUGHTS AND SAID, 'KEEP GOING.' WE LIFTED OFF SAFELY. THE ACFT HAD ALREADY QUICKLY EXITED THE RWY BY THIS TIME. NO FURTHER EVASIVE ACTION WAS NEEDED OR TAKEN. DUE TO RWY SLOPE, IT WAS NOT POSSIBLE TO SEE ACFT ON RAMP OR MIDFIELD TXWY FROM TKOF POINT ON RWY. I THINK THE PROBABLE CAUSE OF THIS INCIDENT WAS FAILURE OF GA ACFT TO MONITOR THE CTAF AND TO ANNOUNCE HIS INTENTIONS/MOVEMENTS, AND BE AWARE OF OURS. IT WOULD HAVE BEEN HELPFUL IF UNICOM (CTAF) COULD HAVE SEEN THIS POSSIBLE CONFLICT AND ALERTED US.

Data retrieved from NASA's ASRS site as of July 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.