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ZSU controller reported a loss of separation and an near midair collision even though they complied with the rules in the faah 7110.65.
| Attributes | |
| ACN | 1658562 |
| Time | |
| Date | 201906 |
| Local Time Of Day | 1201-1800 |
| Place | |
| Locale Reference | ZSU.ARTCC |
| State Reference | PR |
| Environment | |
| Flight Conditions | Marginal |
| Aircraft 1 | |
| Make Model Name | Light Transport |
| Operating Under FAR Part | Part 135 |
| Flight Phase | Cruise |
| Route In Use | Vectors |
| Flight Plan | IFR |
| Aircraft 2 | |
| Make Model Name | Medium Large Transport |
| Operating Under FAR Part | Part 121 |
| Flight Phase | Final Approach |
| Route In Use | Other Instrument Approach |
| Flight Plan | IFR |
| Person 1 | |
| Function | Approach Enroute |
| Qualification | Air Traffic Control Fully Certified |
| Experience | Air Traffic Control Time Certified In Pos 1 (yrs) 4.0 |
| Events | |
| Anomaly | ATC Issue All Types Conflict NMAC Deviation - Procedural Published Material / Policy |
Narrative:
I assigned aircraft X heading 330; altitude 2500 feet on a modified base turn for a visual approach ahead of aircraft Y who was being vectored for the straight-in ILS at 3000 feet. Aircraft X did not have the field in sight as he was approaching the final approach course. I told him there was a change of plans and reiterated the heading and altitude as he crossed the final approach course; and I prepared to vector him for re-sequence. Meanwhile I cleared aircraft Y for the ILS approach. I've replayed this event multiple times and it seems to confirm exactly what I was attempting to do. At the last point prior to aircraft X crossing over the localizer and aircraft Y's flight path there was 4 miles separation. At the first definitive point after flight paths had crossed; 3.68 miles separation existed. Course divergence was 110 degrees. As a result; eventually lateral separation diminished to about 1.5nm at its closest. Aircraft X was not vectored again until lateral separation was established. To me this was textbook 7110.65 5-5-7 passing or diverging. My facility quality assurance office has determined this is a loss of separation and near midair collision. A traffic call may have been warranted.
Original NASA ASRS Text
Title: ZSU Controller reported a loss of separation and an NMAC even though they complied with the rules in the FAAH 7110.65.
Narrative: I assigned Aircraft X heading 330; altitude 2500 feet on a modified base turn for a Visual Approach ahead of Aircraft Y who was being vectored for the straight-in ILS at 3000 feet. Aircraft X did not have the field in sight as he was approaching the final approach course. I told him there was a change of plans and reiterated the heading and altitude as he crossed the final approach course; and I prepared to vector him for re-sequence. Meanwhile I cleared Aircraft Y for the ILS approach. I've replayed this event multiple times and it seems to confirm exactly what I was attempting to do. At the last point prior to Aircraft X crossing over the localizer and Aircraft Y's flight path there was 4 miles separation. At the first definitive point after flight paths had crossed; 3.68 miles separation existed. Course divergence was 110 degrees. As a result; eventually lateral separation diminished to about 1.5nm at its closest. Aircraft X was not vectored again until lateral separation was established. To me this was textbook 7110.65 5-5-7 Passing or Diverging. My facility Quality Assurance office has determined this is a loss of separation and NMAC. A traffic call may have been warranted.
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.