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ZME controller lost required separation when misapplying visual separation in an en route environment.
| Attributes | |
| ACN | 609090 |
| Time | |
| Date | 200402 |
| Day | Tue |
| Local Time Of Day | 0601 To 1200 |
| Place | |
| Locale Reference | navaid : hli.vortac |
| State Reference | MS |
| Altitude | msl bound lower : 18000 msl bound upper : 10700 |
| Environment | |
| Flight Conditions | Mixed |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | artcc : zme.artcc |
| Operator | common carrier : air carrier |
| Make Model Name | B727 Undifferentiated or Other Model |
| Operating Under FAR Part | Part 121 |
| Flight Phase | descent : intermediate altitude |
| Flight Plan | IFR |
| Aircraft 2 | |
| Controlling Facilities | artcc : zme.artcc |
| Operator | general aviation : corporate |
| Make Model Name | King Air C90 E90 |
| Operating Under FAR Part | Part 91 |
| Flight Phase | cruise : level |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | government : faa |
| Function | controller : radar |
| Qualification | controller : radar |
| Experience | controller radar : 18 |
| ASRS Report | 609090 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Events | |
| Anomaly | conflict : airborne less severe non adherence : required legal separation non adherence : published procedure |
| Independent Detector | atc equipment : conflict alert other controllera |
| Resolutory Action | none taken : detected after the fact none taken : anomaly accepted |
| Consequence | faa : investigated Other |
| Miss Distance | horizontal : 21000 vertical : 700 |
| Supplementary | |
| Problem Areas | ATC Human Performance |
| Primary Problem | ATC Human Performance |
| Air Traffic Incident | Operational Error |
Narrative:
The B727 was at FL190, landing at mem. The BE90 was an overflt at FL180. The B727 had the BE90 in sight and said he could maintain visual separation. I issued a clearance to 15000 ft to the B727 and told him to maintain visual separation. After the conflict alert activated, the controller in charge reminded me that this was a misapplication of visual separation. Both aircraft must either be below FL180 or the descending aircraft can be at FL180 or above as long as the other aircraft is below FL180. Hence I lost both vertical and lateral separation because of misapplying the visual separation rule.
Original NASA ASRS Text
Title: ZME CTLR LOST REQUIRED SEPARATION WHEN MISAPPLYING VISUAL SEPARATION IN AN ENRTE ENVIRONMENT.
Narrative: THE B727 WAS AT FL190, LNDG AT MEM. THE BE90 WAS AN OVERFLT AT FL180. THE B727 HAD THE BE90 IN SIGHT AND SAID HE COULD MAINTAIN VISUAL SEPARATION. I ISSUED A CLRNC TO 15000 FT TO THE B727 AND TOLD HIM TO MAINTAIN VISUAL SEPARATION. AFTER THE CONFLICT ALERT ACTIVATED, THE CIC REMINDED ME THAT THIS WAS A MISAPPLICATION OF VISUAL SEPARATION. BOTH ACFT MUST EITHER BE BELOW FL180 OR THE DSNDING ACFT CAN BE AT FL180 OR ABOVE AS LONG AS THE OTHER ACFT IS BELOW FL180. HENCE I LOST BOTH VERT AND LATERAL SEPARATION BECAUSE OF MISAPPLYING THE VISUAL SEPARATION RULE.
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.