Narrative:

Climbing out of crw on vectors to our first fix we were advised by ATC about a flight of several C140's. A pair of them in formation, appeared on our tcasi at a range of 5- 6 mi. At first, it looked like we would be able to climb and pass through their altitude with no conflict. Soon, we realized that this was incorrect. At 1200 ft horizontal and 200 ft vertical we leveled the aircraft and turned left to avoid a possible collision. The controller asked if we had turned left. The captain responded affirmative to the question. The controller replied 'that's fine, but I'd like to know about it.' the captain said the maneuver was unexpected and he didn't have time to report the turn, but he apologized for being unable to advise the controller. I believe the conflict resulted from overestimating our climb performance and underestimating our closure rate. I should have slowed our rate of climb down or leveled off. Also, looking to the right at 2 small aircraft, I couldn't see the tcasi. I couldn't see their direction of flight until the last few seconds before our turn to the left. Supplemental information from acn 380281: in retrospect, I believe the conflict resulted from my underestimating our rate of closure. If I had it to do over, I would have leveled off earlier and not needed the turn off course. I might also have overestimated our climb performance. A contributing factor to this incident may have been a false sense of security provided by the tcasi. Without it, I doubt that I would have even attempted to out climb the traffic.

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Original NASA ASRS Text

Title: EMB120 FLC PERFORMS AN EVASIVE ACTION TO MISS 2 C140'S FLYING OPPOSITE DIRECTION. FLC MISJUDGED THEIR ACFT'S PERFORMANCE CAPABILITIES AND THE RATE OF CLOSURE.

Narrative: CLBING OUT OF CRW ON VECTORS TO OUR FIRST FIX WE WERE ADVISED BY ATC ABOUT A FLT OF SEVERAL C140'S. A PAIR OF THEM IN FORMATION, APPEARED ON OUR TCASI AT A RANGE OF 5- 6 MI. AT FIRST, IT LOOKED LIKE WE WOULD BE ABLE TO CLB AND PASS THROUGH THEIR ALT WITH NO CONFLICT. SOON, WE REALIZED THAT THIS WAS INCORRECT. AT 1200 FT HORIZ AND 200 FT VERT WE LEVELED THE ACFT AND TURNED L TO AVOID A POSSIBLE COLLISION. THE CTLR ASKED IF WE HAD TURNED L. THE CAPT RESPONDED AFFIRMATIVE TO THE QUESTION. THE CTLR REPLIED 'THAT'S FINE, BUT I'D LIKE TO KNOW ABOUT IT.' THE CAPT SAID THE MANEUVER WAS UNEXPECTED AND HE DIDN'T HAVE TIME TO RPT THE TURN, BUT HE APOLOGIZED FOR BEING UNABLE TO ADVISE THE CTLR. I BELIEVE THE CONFLICT RESULTED FROM OVERESTIMATING OUR CLB PERFORMANCE AND UNDERESTIMATING OUR CLOSURE RATE. I SHOULD HAVE SLOWED OUR RATE OF CLB DOWN OR LEVELED OFF. ALSO, LOOKING TO THE R AT 2 SMALL ACFT, I COULDN'T SEE THE TCASI. I COULDN'T SEE THEIR DIRECTION OF FLT UNTIL THE LAST FEW SECONDS BEFORE OUR TURN TO THE L. SUPPLEMENTAL INFO FROM ACN 380281: IN RETROSPECT, I BELIEVE THE CONFLICT RESULTED FROM MY UNDERESTIMATING OUR RATE OF CLOSURE. IF I HAD IT TO DO OVER, I WOULD HAVE LEVELED OFF EARLIER AND NOT NEEDED THE TURN OFF COURSE. I MIGHT ALSO HAVE OVERESTIMATED OUR CLB PERFORMANCE. A CONTRIBUTING FACTOR TO THIS INCIDENT MAY HAVE BEEN A FALSE SENSE OF SECURITY PROVIDED BY THE TCASI. WITHOUT IT, I DOUBT THAT I WOULD HAVE EVEN ATTEMPTED TO OUT CLB THE TFC.

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.