Narrative:

During departure from jfk on climb out with clearance to 11000 ft the departure controller asked us to expedite climb through 8000 ft. Co-pilot was flying. Maximum rate climb speed was selected as was climb power, since derated climb power had been selected after cleanup and acceleration to 250 KTS. During the climb the controller advised us twice of traffic (IFR) at 7000 ft and 4 mi off to our right that I believed to be the reason for the expedited climb request. We were on an assigned heading of 220 degrees. Passing about 6800 ft, the controller called traffic, opposite direction at 7500 ft (VFR) that he was not talking to. Then almost immediately, he said 'maintain 7000 ft.' by that time our altitude was 7100 ft rate of climb 1800 FPM. Immediately we got a TCASII alert, traffic, traffic,' directly followed by the controller canceling the 'maintain 7000 ft, continue to climb.' our climb rate was down to 1400 FPM at 7300 ft, and very quickly after 'traffic, traffic,' TCASII followed with 'maintain vertical speed' and displayed an ivsi command climb of about 2000 FPM which was smoothly followed. Visual sight was obtained at about 1 mi by co-pilot. I saw the aircraft (single engine low wing) at about 1/2 mi, and watched as it passed beneath us in a slight right bank. It was just left of a direct head on track. TCASII showed the red square traffic symbol passing beneath us at 200 ft as we continued our climb. My observations: TCASII is accurate. Following it's command averted a potential disaster. The controller's instructions were also correct, but based on his screen information which I believe gets to him with some amount of time delay. I would not fault the controller. His information display is the problem. TCASII is a more accurate real time display. However, his workload may have been a factor in our being in that position, in that the VFR traffic was mentioned later in our climb and not until we were within about 500 ft vertical separation. After my initial reservation about TCASII, it has gained my confidence.

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Original NASA ASRS Text

Title: NMAC - TCASII, AN ALERT CTLR AND A GOOD SCAN BY THE FLC OF AN ACR AVOIDS A VFR ACFT BY 200 FT.

Narrative: DURING DEP FROM JFK ON CLB OUT WITH CLRNC TO 11000 FT THE DEP CTLR ASKED US TO EXPEDITE CLB THROUGH 8000 FT. CO-PLT WAS FLYING. MAX RATE CLB SPD WAS SELECTED AS WAS CLB PWR, SINCE DERATED CLB PWR HAD BEEN SELECTED AFTER CLEANUP AND ACCELERATION TO 250 KTS. DURING THE CLB THE CTLR ADVISED US TWICE OF TFC (IFR) AT 7000 FT AND 4 MI OFF TO OUR R THAT I BELIEVED TO BE THE REASON FOR THE EXPEDITED CLB REQUEST. WE WERE ON AN ASSIGNED HDG OF 220 DEGS. PASSING ABOUT 6800 FT, THE CTLR CALLED TFC, OPPOSITE DIRECTION AT 7500 FT (VFR) THAT HE WAS NOT TALKING TO. THEN ALMOST IMMEDIATELY, HE SAID 'MAINTAIN 7000 FT.' BY THAT TIME OUR ALT WAS 7100 FT RATE OF CLB 1800 FPM. IMMEDIATELY WE GOT A TCASII ALERT, TFC, TFC,' DIRECTLY FOLLOWED BY THE CTLR CANCELING THE 'MAINTAIN 7000 FT, CONTINUE TO CLB.' OUR CLB RATE WAS DOWN TO 1400 FPM AT 7300 FT, AND VERY QUICKLY AFTER 'TFC, TFC,' TCASII FOLLOWED WITH 'MAINTAIN VERT SPD' AND DISPLAYED AN IVSI COMMAND CLB OF ABOUT 2000 FPM WHICH WAS SMOOTHLY FOLLOWED. VISUAL SIGHT WAS OBTAINED AT ABOUT 1 MI BY CO-PLT. I SAW THE ACFT (SINGLE ENG LOW WING) AT ABOUT 1/2 MI, AND WATCHED AS IT PASSED BENEATH US IN A SLIGHT R BANK. IT WAS JUST L OF A DIRECT HEAD ON TRACK. TCASII SHOWED THE RED SQUARE TFC SYMBOL PASSING BENEATH US AT 200 FT AS WE CONTINUED OUR CLB. MY OBSERVATIONS: TCASII IS ACCURATE. FOLLOWING IT'S COMMAND AVERTED A POTENTIAL DISASTER. THE CTLR'S INSTRUCTIONS WERE ALSO CORRECT, BUT BASED ON HIS SCREEN INFO WHICH I BELIEVE GETS TO HIM WITH SOME AMOUNT OF TIME DELAY. I WOULD NOT FAULT THE CTLR. HIS INFO DISPLAY IS THE PROB. TCASII IS A MORE ACCURATE REAL TIME DISPLAY. HOWEVER, HIS WORKLOAD MAY HAVE BEEN A FACTOR IN OUR BEING IN THAT POS, IN THAT THE VFR TFC WAS MENTIONED LATER IN OUR CLB AND NOT UNTIL WE WERE WITHIN ABOUT 500 FT VERT SEPARATION. AFTER MY INITIAL RESERVATION ABOUT TCASII, IT HAS GAINED MY CONFIDENCE.

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.