Narrative:

Widebody transport X was proceeding sebnd descending to 10000', inbound to sju. Mdt Y had departed sju, proceeding west and climbing to 18000'. Mdt Y was pointed out properly by the adjoining sector (R2) and transiting my airspace (R6). It became apparent that widebody transport X heading was not sufficient to maintain sep with the mdt Y, so I issued widebody transport X a left turn first to heading 100 degrees, then to 90 degrees (east). Widebody transport X acknowledged the turn, but did not appear to initiate it for at least another 7-8 mi. At this time the R2 controller leveled the mdt Y off at 13000', and turned it left 30 degrees. The controller (R2) informed me of this and suggested I stop widebody transport X descent. I cleared widebody transport X to 14000', at which time his mode C altitude read just above that. The aircraft read back 13000' and continued down through 14000'. Soon after this, standard sep was lost. No evasive action was taken by either pilot. They passed east and west with approximately 2 mi between and 800'. Reaction time, both for the pilot and myself, could have been better.

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Original NASA ASRS Text

Title: LESS THAN STANDARD SEPARATION BETWEEN WDB DESCENDING AND MDT CLIMBING. POINTOUT MADE FROM ADJACENT SECTOR AND WDB MISINTERPRETED ALT ASSIGNMENT.

Narrative: WDB X WAS PROCEEDING SEBND DSNDING TO 10000', INBND TO SJU. MDT Y HAD DEPARTED SJU, PROCEEDING W AND CLBING TO 18000'. MDT Y WAS POINTED OUT PROPERLY BY THE ADJOINING SECTOR (R2) AND TRANSITING MY AIRSPACE (R6). IT BECAME APPARENT THAT WDB X HDG WAS NOT SUFFICIENT TO MAINTAIN SEP WITH THE MDT Y, SO I ISSUED WDB X A LEFT TURN FIRST TO HDG 100 DEGS, THEN TO 90 DEGS (E). WDB X ACKNOWLEDGED THE TURN, BUT DID NOT APPEAR TO INITIATE IT FOR AT LEAST ANOTHER 7-8 MI. AT THIS TIME THE R2 CTLR LEVELED THE MDT Y OFF AT 13000', AND TURNED IT LEFT 30 DEGS. THE CTLR (R2) INFORMED ME OF THIS AND SUGGESTED I STOP WDB X DSCNT. I CLRED WDB X TO 14000', AT WHICH TIME HIS MODE C ALT READ JUST ABOVE THAT. THE ACFT READ BACK 13000' AND CONTINUED DOWN THROUGH 14000'. SOON AFTER THIS, STANDARD SEP WAS LOST. NO EVASIVE ACTION WAS TAKEN BY EITHER PLT. THEY PASSED E AND W WITH APPROX 2 MI BTWN AND 800'. REACTION TIME, BOTH FOR THE PLT AND MYSELF, COULD HAVE BEEN BETTER.

Data retrieved from NASA's ASRS site as of August 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.