Narrative:

Aircraft was departing la guardia on a la guardia 3 departure, whitestone climb to 5000' MSL. While climbing through 4000' on an assigned heading of 270 degree a turn to 180 degree was give by departure control. As the turn was initiated departure control called traffic in the 2 O'clock position. Departure control then called for a hard bank to 180 degree (he mistakenly said to the right). Since the aircraft was in a 30 degree left bank the PF was not able to see out the right side. The conflicting traffic told departure that he had our aircraft visly and at that time the first officer saw the traffic converging on our aircraft. Due to the altitude and converging course of the traffic the first officer advised stopping the climb. The aircraft was levelled at 4500' MSL and the traffic passed over the top of our plane approximately 5000' MSL (500' vertical sep). If we had not stopped our climb or if we had reversed turn to the right as what I believe was mistakenly advised by the departure controller I believe we would have had a mid-air collision. Human factors. The controller did not recognize our conflicting courses early enough. The pilot of the other aircraft took no evasive action even though he told departure control that he had us visly. Supplemental information from acn 159348. While climbing through 4000' on radar vector a turn to 270 was given. A farther turn to 180 degree was then given and traffic called at 2 O'clock. A hard turn to 100 degree was then given the controller then said to the other aircraft 'you have him in sight? Good.' approaching 4500' the first officer saw the other traffic on an intersecting course and advised the captain (flying) to level off.

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Original NASA ASRS Text

Title: DEP CTLR SEES POTENTIAL CONFLICT AND TRIES TO RESOLVE IT, BUT NMAC OCCURS ANYWAY. DEP ACFT OFF ADJACENT ARPTS AND FLT CREW VIGILANCE INTERVENTION SAVE THE DAY.

Narrative: ACFT WAS DEPARTING LA GUARDIA ON A LA GUARDIA 3 DEP, WHITESTONE CLB TO 5000' MSL. WHILE CLBING THROUGH 4000' ON AN ASSIGNED HDG OF 270 DEG A TURN TO 180 DEG WAS GIVE BY DEP CTL. AS THE TURN WAS INITIATED DEP CTL CALLED TFC IN THE 2 O'CLOCK POS. DEP CTL THEN CALLED FOR A HARD BANK TO 180 DEG (HE MISTAKENLY SAID TO THE R). SINCE THE ACFT WAS IN A 30 DEG L BANK THE PF WAS NOT ABLE TO SEE OUT THE R SIDE. THE CONFLICTING TFC TOLD DEP THAT HE HAD OUR ACFT VISLY AND AT THAT TIME THE F/O SAW THE TFC CONVERGING ON OUR ACFT. DUE TO THE ALT AND CONVERGING COURSE OF THE TFC THE F/O ADVISED STOPPING THE CLB. THE ACFT WAS LEVELLED AT 4500' MSL AND THE TFC PASSED OVER THE TOP OF OUR PLANE APPROX 5000' MSL (500' VERT SEP). IF WE HAD NOT STOPPED OUR CLB OR IF WE HAD REVERSED TURN TO THE R AS WHAT I BELIEVE WAS MISTAKENLY ADVISED BY THE DEP CTLR I BELIEVE WE WOULD HAVE HAD A MID-AIR COLLISION. HUMAN FACTORS. THE CTLR DID NOT RECOGNIZE OUR CONFLICTING COURSES EARLY ENOUGH. THE PLT OF THE OTHER ACFT TOOK NO EVASIVE ACTION EVEN THOUGH HE TOLD DEP CTL THAT HE HAD US VISLY. SUPPLEMENTAL INFO FROM ACN 159348. WHILE CLBING THROUGH 4000' ON RADAR VECTOR A TURN TO 270 WAS GIVEN. A FARTHER TURN TO 180 DEG WAS THEN GIVEN AND TFC CALLED AT 2 O'CLOCK. A HARD TURN TO 100 DEG WAS THEN GIVEN THE CTLR THEN SAID TO THE OTHER ACFT 'YOU HAVE HIM IN SIGHT? GOOD.' APCHING 4500' THE F/O SAW THE OTHER TFC ON AN INTERSECTING COURSE AND ADVISED THE CAPT (FLYING) TO LEVEL OFF.

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.