Narrative:

Aircraft X was on the airway M201 traveling northwest bound from sector 87 to sector 21 at FL350. Aircraft Y was in sector 65 airspace approaching the fix slatn; which is the fix on the radar/non-radar boundary; with his next point being 42n060w at FL350. Aircraft Z was in sector 65 airspace approaching the fix slatn; which is the fix on the radar/non-radar boundary; with his next point being 42n060w at FL370. Aircraft Y was coordinated by sector 65 to me at FL350; estimating slatn and was probed against all known traffic via the Ocean21 system. No conflicts were found at FL350 and the aircraft was approved. Aircraft Z was coordinated by sector 65 to me at FL370; estimating slatn and was probed against all known traffic via the Ocean21 system. No conflicts were found at FL370 and the aircraft was approved. At some time sector 65 called to coordinate another aircraft which called my attention to the Ocean21 geographic display map in the area of slatn. At this point I noted that the flight paths of aircraft Y and aircraft X did not look good to me. I checked the times and saw that aircraft Y estimated slatn at XX00z and that aircraft X estimated dryed at XX01z. Thinking that the conflict probe had failed I scanned for traffic at FL340 and issued a clearance to aircraft X to descend to FL340; aircraft Z reported at FL340 at XX03z. I believe there was a potential loss of separation between the aircraft X and aircraft Y.a further examination of the situation revealed that aircraft Y and aircraft X appeared to have 1 or 2 minutes on the cross. Also aircraft X; when probed to FL370; did not show a conflict with aircraft Z at FL370. Aircraft X and aircraft Z were never at the same altitude at the same time and were not in conflict. This note is just to show that the failure of the probe was not a singular event. There were two aircraft that did not show potential or actual conflicts against the aircraft X. Aircraft X did probe correctly against other aircraft in the system.I am not well versed in the technical manner in which the Ocean21 conflict probe measures; calculates and determines conflicts between aircraft; but whatever caused it to not think that these aircraft were in conflict needs to be addressed and corrected.

Google
 

Original NASA ASRS Text

Title: ZNY Oceanic Developmental reports of conflict between two aircraft that he observed prior to a loss of separation. Computer malfunction in not showing a conflict led to the problem.

Narrative: Aircraft X was on the airway M201 traveling northwest bound from Sector 87 to Sector 21 at FL350. Aircraft Y was in Sector 65 airspace approaching the fix SLATN; which is the fix on the radar/non-radar boundary; with his next point being 42n060w at FL350. Aircraft Z was in Sector 65 airspace approaching the fix SLATN; which is the fix on the radar/non-radar boundary; with his next point being 42n060w at FL370. Aircraft Y was coordinated by Sector 65 to me at FL350; estimating SLATN and was probed against all known traffic via the Ocean21 system. No conflicts were found at FL350 and the aircraft was approved. Aircraft Z was coordinated by Sector 65 to me at FL370; estimating SLATN and was probed against all known traffic via the Ocean21 system. No conflicts were found at FL370 and the aircraft was approved. At some time Sector 65 called to coordinate another aircraft which called my attention to the Ocean21 geographic display map in the area of SLATN. At this point I noted that the flight paths of Aircraft Y and Aircraft X did not look good to me. I checked the times and saw that Aircraft Y estimated SLATN at XX00z and that Aircraft X estimated DRYED at XX01z. Thinking that the conflict probe had failed I scanned for traffic at FL340 and issued a clearance to Aircraft X to descend to FL340; Aircraft Z reported at FL340 at XX03z. I believe there was a potential loss of separation between the Aircraft X and Aircraft Y.A further examination of the situation revealed that Aircraft Y and Aircraft X appeared to have 1 or 2 minutes on the cross. Also Aircraft X; when probed to FL370; did not show a conflict with Aircraft Z at FL370. Aircraft X and Aircraft Z were never at the same altitude at the same time and were not in conflict. This note is just to show that the failure of the probe was not a singular event. There were two aircraft that did not show potential or actual conflicts against the Aircraft X. Aircraft X did probe correctly against other aircraft in the system.I am not well versed in the technical manner in which the Ocean21 conflict probe measures; calculates and determines conflicts between aircraft; but whatever caused it to not think that these aircraft were in conflict needs to be addressed and corrected.

Data retrieved from NASA's ASRS site 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.