Narrative:

Cid tower cleared us (air carrier X flight) for takeoff runway 27 to 5000 ft. We were very light (weight) with a high rate of climb. Almost immediately after takeoff we received a TCASII alert, followed by a descend command. At approximately this same time, we received a TA from ATC, but between the TCASII verbal alerts, the ATC advisories and the busy cockpit, I don't remember the exact timing. After contacting departure control, I asked about the traffic. It was a helicopter at 2500 ft and had been in contact with ATC (flying south). There is absolutely no doubt in my mind that without aggressive response to stop our climb and a turn, we would've collided. I estimate that we were within 300-400 ft of impact. The TCASII alert came before any tower advisory and the TCASII probably saved many lives. With a 20 degree pitch for climb and a rate of climb of 4000 FPM (approximately), there is not much time to react. The control tower should've never cleared us for takeoff into known traffic -- especially without giving us an advisory.

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Original NASA ASRS Text

Title: FLC OF AN MLG STOPPED INITIAL CLBOUT IN RESPONSE TO TCASII RA TO DSND FOR A HELI FLYING THROUGH THE CLASS C AIRSPACE AT 2500 FT.

Narrative: CID TWR CLRED US (ACR X FLT) FOR TKOF RWY 27 TO 5000 FT. WE WERE VERY LIGHT (WT) WITH A HIGH RATE OF CLB. ALMOST IMMEDIATELY AFTER TKOF WE RECEIVED A TCASII ALERT, FOLLOWED BY A DSND COMMAND. AT APPROX THIS SAME TIME, WE RECEIVED A TA FROM ATC, BUT BTWN THE TCASII VERBAL ALERTS, THE ATC ADVISORIES AND THE BUSY COCKPIT, I DON'T REMEMBER THE EXACT TIMING. AFTER CONTACTING DEP CTL, I ASKED ABOUT THE TFC. IT WAS A HELI AT 2500 FT AND HAD BEEN IN CONTACT WITH ATC (FLYING S). THERE IS ABSOLUTELY NO DOUBT IN MY MIND THAT WITHOUT AGGRESSIVE RESPONSE TO STOP OUR CLB AND A TURN, WE WOULD'VE COLLIDED. I ESTIMATE THAT WE WERE WITHIN 300-400 FT OF IMPACT. THE TCASII ALERT CAME BEFORE ANY TWR ADVISORY AND THE TCASII PROBABLY SAVED MANY LIVES. WITH A 20 DEG PITCH FOR CLB AND A RATE OF CLB OF 4000 FPM (APPROX), THERE IS NOT MUCH TIME TO REACT. THE CTL TWR SHOULD'VE NEVER CLRED US FOR TKOF INTO KNOWN TFC -- ESPECIALLY WITHOUT GIVING US AN ADVISORY.

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.