Narrative:

I was working local when air carrier X checked in for VOR approach to runway 13L at jfk. Air carrier X was instructed previous arrival had executed a missed approach at decision ht. I noticed air carrier X ground speed drop to 130 KTS and asked if he could increase 20 KTS for traffic in trail. Air carrier X replied negative. I asked air carrier X to say airspeed. He replied 145 KTS. I then called air carrier Y. The pilot responded (later information showed approach told the pilot to contact me 4 mins prior). I issued air carrier X 2 O'clock 2 mi. Air carrier X calls he is on a go around. I instruct air carrier X heading 090 maintain 2000. I inform air carrier Y of air carrier X traffic is on a miss eastbound. Air carrier Y cleared to land runway 13L. Next transmission is to air carrier X turn right heading 130 maintain 2000. Air carrier Y reads back the heading right 130 and advises he is on the go. I instruct air carrier Y negative fly heading 040 (no altitude). Next transmission is to air carrier X right 130 maintain 2000, which is read back by air carrier X. I then instruct air carrier Y turn right heading 130 maintain 2000. Air carrier Y does not acknowledge. At this time, both data blocks are in the 10 O'clock position. Air carrier X tag is covering air carrier Y altitude and gndspd. As air carrier X turns southeast, air carrier Y altitude is exposed showing 3000. I saw departure widebody transport from lga (8 mi north of jfk) climbing out of 2600. I issued air carrier Y turn right immediately heading 130 maintain 2000, traffic 10 O'clock, 2 mi sbound. Air carrier Y reads back 130 maintain 3000. I instruct air carrier Y negative, maintain 2000, which he reads back. The lga widebody transport came within 1 mi and 100 ft of air carrier Y. That night the incident was classified a pilot deviation, but review the following day was overturned to an operational deviation on my part because air carrier Y did not read back instructions of 130 maintain 2000.

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Original NASA ASRS Text

Title: ACR Y CLB TO WRONG ALT OCCUPIED ALT HAD LTSS FROM WDB. SYS ERROR.

Narrative: I WAS WORKING LCL WHEN ACR X CHKED IN FOR VOR APCH TO RWY 13L AT JFK. ACR X WAS INSTRUCTED PREVIOUS ARR HAD EXECUTED A MISSED APCH AT DECISION HT. I NOTICED ACR X GND SPD DROP TO 130 KTS AND ASKED IF HE COULD INCREASE 20 KTS FOR TFC IN TRAIL. ACR X REPLIED NEGATIVE. I ASKED ACR X TO SAY AIRSPD. HE REPLIED 145 KTS. I THEN CALLED ACR Y. THE PLT RESPONDED (LATER INFO SHOWED APCH TOLD THE PLT TO CONTACT ME 4 MINS PRIOR). I ISSUED ACR X 2 O'CLOCK 2 MI. ACR X CALLS HE IS ON A GAR. I INSTRUCT ACR X HDG 090 MAINTAIN 2000. I INFORM ACR Y OF ACR X TFC IS ON A MISS EBOUND. ACR Y CLRED TO LAND RWY 13L. NEXT XMISSION IS TO ACR X TURN R HDG 130 MAINTAIN 2000. ACR Y READS BACK THE HDG R 130 AND ADVISES HE IS ON THE GO. I INSTRUCT ACR Y NEGATIVE FLY HDG 040 (NO ALT). NEXT XMISSION IS TO ACR X R 130 MAINTAIN 2000, WHICH IS READ BACK BY ACR X. I THEN INSTRUCT ACR Y TURN R HDG 130 MAINTAIN 2000. ACR Y DOES NOT ACKNOWLEDGE. AT THIS TIME, BOTH DATA BLOCKS ARE IN THE 10 O'CLOCK POS. ACR X TAG IS COVERING ACR Y ALT AND GNDSPD. AS ACR X TURNS SE, ACR Y ALT IS EXPOSED SHOWING 3000. I SAW DEP WDB FROM LGA (8 MI N OF JFK) CLBING OUT OF 2600. I ISSUED ACR Y TURN R IMMEDIATELY HDG 130 MAINTAIN 2000, TFC 10 O'CLOCK, 2 MI SBOUND. ACR Y READS BACK 130 MAINTAIN 3000. I INSTRUCT ACR Y NEGATIVE, MAINTAIN 2000, WHICH HE READS BACK. THE LGA WDB CAME WITHIN 1 MI AND 100 FT OF ACR Y. THAT NIGHT THE INCIDENT WAS CLASSIFIED A PLTDEV, BUT REVIEW THE FOLLOWING DAY WAS OVERTURNED TO AN OPDEV ON MY PART BECAUSE ACR Y DID NOT READ BACK INSTRUCTIONS OF 130 MAINTAIN 2000.

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.