Narrative:

While taxiing out to runway, monitored unicom frequency during a busy weekend day. Performed run-up while monitoring traffic. Announced over frequency departing runway 15 and pulled onto runway. Began accelerating down runway and noticed shadow, then aircraft 50 ft above traveling in same direction. I had pulled out in front of an aircraft on short final. Continued takeoff (not enough room to abort). In the future, I have learned to look even better for traffic and realize some traffic may not be using unicom to report position. Increased vigilance at uncontrolled airports are a must to reduce the chance of collision.

Google
 

Original NASA ASRS Text

Title: C310 PLT ON CTAF FREQ TAKES OFF AFTER ANNOUNCING DEP AND SPOTS A C152 ABOVE ON AN ABORTED LNDG ON THE SAME RWY.

Narrative: WHILE TAXIING OUT TO RWY, MONITORED UNICOM FREQ DURING A BUSY WEEKEND DAY. PERFORMED RUN-UP WHILE MONITORING TFC. ANNOUNCED OVER FREQ DEPARTING RWY 15 AND PULLED ONTO RWY. BEGAN ACCELERATING DOWN RWY AND NOTICED SHADOW, THEN ACFT 50 FT ABOVE TRAVELING IN SAME DIRECTION. I HAD PULLED OUT IN FRONT OF AN ACFT ON SHORT FINAL. CONTINUED TKOF (NOT ENOUGH ROOM TO ABORT). IN THE FUTURE, I HAVE LEARNED TO LOOK EVEN BETTER FOR TFC AND REALIZE SOME TFC MAY NOT BE USING UNICOM TO RPT POS. INCREASED VIGILANCE AT UNCTLED ARPTS ARE A MUST TO REDUCE THE CHANCE OF COLLISION.

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.