Narrative:

We were being vectored for an ILS approach to runway 4 at lga. We were IMC, level at 2700 ft MSL, about 10-15 NM southwest of the airport. Lga approach control was very busy, and we had already heard the controller tell 2 different aircraft to break off their approachs because of too tight spacing, to be vectored back around for another approach. All of a sudden, the controller called us, in a voice about 3 octaves higher than normal, to 'turn right immediately to 090 degree heading' (about a 90 degree turn) followed by 'and climb to 4000 ft' (in an equally urgent/panicky tone). At the same time, he was issuing turn instructions to an air carrier Y flight. Because of the panicky tone of his voice, I actually perceived that a midair collision may be imminent, so I disconnected the autoplt and rolled into a 50-60 degree bank, in an 'escape' maneuver. (Our TCASII never gave us an alert, but there was no time to determine if it was operating properly.) we were IMC the whole time, and for a period of at best 8-10 seconds, we weren't sure if another aircraft would appear across our windscreen. I then asked if we were clear of traffic, and he said that we were, and that we had never been closer than 2 - 2 1/2 NM lateral separation, but that we were at the same altitude. I spoke with new york TRACON supervisor on the ground later, and he confirmed that it had been his controller's error. I told ATC supervisor that it would have greatly helped our perception of the situation if the controller had somehow been able to communicate that a collision was not imminent, because rolling into a 60 degree bank could potentially have caused problems of its own. He agreed that that would have been helpful, and added that they had received 2 conflict alerts at their TRACON. He said the 2 planes were at the same altitude, but never got closer than 2 1/2 NM apart.

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Original NASA ASRS Text

Title: APCH CTLR RECEIVED CONFLICT ALERT ON 2 ACR ACFT DURING VECTORS FOR ILS APCH RESULTING IN THE CTLR INSTRUCTING EACH ACFT TO TURN AND THE RPTR TO CLB. THE RPTR MADE A 60 DEG BANK TO ASSURE SEPARATION DUE TO THE URGENCY OF THE CTLR'S VOICE. BOTH ACFT WERE IN IMC.

Narrative: WE WERE BEING VECTORED FOR AN ILS APCH TO RWY 4 AT LGA. WE WERE IMC, LEVEL AT 2700 FT MSL, ABOUT 10-15 NM SW OF THE ARPT. LGA APCH CTL WAS VERY BUSY, AND WE HAD ALREADY HEARD THE CTLR TELL 2 DIFFERENT ACFT TO BREAK OFF THEIR APCHS BECAUSE OF TOO TIGHT SPACING, TO BE VECTORED BACK AROUND FOR ANOTHER APCH. ALL OF A SUDDEN, THE CTLR CALLED US, IN A VOICE ABOUT 3 OCTAVES HIGHER THAN NORMAL, TO 'TURN R IMMEDIATELY TO 090 DEG HDG' (ABOUT A 90 DEG TURN) FOLLOWED BY 'AND CLB TO 4000 FT' (IN AN EQUALLY URGENT/PANICKY TONE). AT THE SAME TIME, HE WAS ISSUING TURN INSTRUCTIONS TO AN ACR Y FLT. BECAUSE OF THE PANICKY TONE OF HIS VOICE, I ACTUALLY PERCEIVED THAT A MIDAIR COLLISION MAY BE IMMINENT, SO I DISCONNECTED THE AUTOPLT AND ROLLED INTO A 50-60 DEG BANK, IN AN 'ESCAPE' MANEUVER. (OUR TCASII NEVER GAVE US AN ALERT, BUT THERE WAS NO TIME TO DETERMINE IF IT WAS OPERATING PROPERLY.) WE WERE IMC THE WHOLE TIME, AND FOR A PERIOD OF AT BEST 8-10 SECONDS, WE WEREN'T SURE IF ANOTHER ACFT WOULD APPEAR ACROSS OUR WINDSCREEN. I THEN ASKED IF WE WERE CLR OF TFC, AND HE SAID THAT WE WERE, AND THAT WE HAD NEVER BEEN CLOSER THAN 2 - 2 1/2 NM LATERAL SEPARATION, BUT THAT WE WERE AT THE SAME ALT. I SPOKE WITH NEW YORK TRACON SUPVR ON THE GND LATER, AND HE CONFIRMED THAT IT HAD BEEN HIS CTLR'S ERROR. I TOLD ATC SUPVR THAT IT WOULD HAVE GREATLY HELPED OUR PERCEPTION OF THE SIT IF THE CTLR HAD SOMEHOW BEEN ABLE TO COMMUNICATE THAT A COLLISION WAS NOT IMMINENT, BECAUSE ROLLING INTO A 60 DEG BANK COULD POTENTIALLY HAVE CAUSED PROBS OF ITS OWN. HE AGREED THAT THAT WOULD HAVE BEEN HELPFUL, AND ADDED THAT THEY HAD RECEIVED 2 CONFLICT ALERTS AT THEIR TRACON. HE SAID THE 2 PLANES WERE AT THE SAME ALT, BUT NEVER GOT CLOSER THAN 2 1/2 NM APART.

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.