Narrative:

Departing runway 9L at ord, flaps 5 degrees , cleared to 5000 ft MSL, and right heading 140 degrees. While climbing through 1900 ft MSL and in the turn to 140, we received a TCASII RA to descend. On the TCASII, there was a red aircraft displayed with an altitude of 1900 ft within 1 mi to the right of our aircraft moving toward us. We did not have the aircraft visually. The PF lowered the nose when the RA was issued, and the PNF told the tower about the TCASII descent. Within a few seconds of the TCASII RA, we received a clear of conflict message and continued our climb. When we asked the tower about the aircraft involved, he informed us it was an air carrier jet doing a go around off runway 4R and he had us in sight. I would like to know: 1) when didn't the tower tell us about the traffic? 2) did the traffic get an RA? 3) what was our separation from that aircraft at our closest point? Callback: no additional substantive information was garnered from the callback. The reporter stated that the resolution maneuver was a 'descend now,' which indicates a greater level of conflict than the lesser 'descend.' we discussed the TCASII logic and the fact that a RA requires coordination responses from both aircraft and that, therefore, the other aircraft must have also received a RA. Reporter did comment that the descend maneuver at a time when the aircraft was in a high angle of attack confign was a dramatic attitude change and was more unnerving as a result.

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Original NASA ASRS Text

Title: B735 ON DEP FROM RWY 9L AT ORD HAS TCASII RA RELATIVE TO GAR TFC OFF RWY 4R.

Narrative: DEPARTING RWY 9L AT ORD, FLAPS 5 DEGS , CLRED TO 5000 FT MSL, AND R HDG 140 DEGS. WHILE CLBING THROUGH 1900 FT MSL AND IN THE TURN TO 140, WE RECEIVED A TCASII RA TO DSND. ON THE TCASII, THERE WAS A RED ACFT DISPLAYED WITH AN ALT OF 1900 FT WITHIN 1 MI TO THE R OF OUR ACFT MOVING TOWARD US. WE DID NOT HAVE THE ACFT VISUALLY. THE PF LOWERED THE NOSE WHEN THE RA WAS ISSUED, AND THE PNF TOLD THE TWR ABOUT THE TCASII DSCNT. WITHIN A FEW SECONDS OF THE TCASII RA, WE RECEIVED A CLR OF CONFLICT MESSAGE AND CONTINUED OUR CLB. WHEN WE ASKED THE TWR ABOUT THE ACFT INVOLVED, HE INFORMED US IT WAS AN ACR JET DOING A GAR OFF RWY 4R AND HE HAD US IN SIGHT. I WOULD LIKE TO KNOW: 1) WHEN DIDN'T THE TWR TELL US ABOUT THE TFC? 2) DID THE TFC GET AN RA? 3) WHAT WAS OUR SEPARATION FROM THAT ACFT AT OUR CLOSEST POINT? CALLBACK: NO ADDITIONAL SUBSTANTIVE INFO WAS GARNERED FROM THE CALLBACK. THE RPTR STATED THAT THE RESOLUTION MANEUVER WAS A 'DSND NOW,' WHICH INDICATES A GREATER LEVEL OF CONFLICT THAN THE LESSER 'DSND.' WE DISCUSSED THE TCASII LOGIC AND THE FACT THAT A RA REQUIRES COORD RESPONSES FROM BOTH ACFT AND THAT, THEREFORE, THE OTHER ACFT MUST HAVE ALSO RECEIVED A RA. RPTR DID COMMENT THAT THE DSND MANEUVER AT A TIME WHEN THE ACFT WAS IN A HIGH ANGLE OF ATTACK CONFIGN WAS A DRAMATIC ATTITUDE CHANGE AND WAS MORE UNNERVING AS A RESULT.

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.