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Controller cleared the large transport to descend which resulted in less than standard separation with an aircraft below the large transport.
| Attributes | |
| ACN | 169549 |
| Time | |
| Date | 199102 |
| Day | Mon |
| Local Time Of Day | 1201 To 1800 |
| Place | |
| Locale Reference | atc facility : sfo |
| State Reference | CA |
| Altitude | msl bound lower : 11000 msl bound upper : 11600 |
| Environment | |
| Flight Conditions | VMC |
| Light | Daylight |
| Aircraft 1 | |
| Operator | common carrier : air carrier |
| Make Model Name | Large Transport, Low Wing, 3 Turbojet Eng |
| Flight Phase | descent other |
| Route In Use | arrival other arrival star : star enroute airway : zoa |
| Flight Plan | IFR |
| Aircraft 2 | |
| Operator | common carrier : air carrier |
| Make Model Name | Light Transport, Low Wing, 2 Turboprop Eng |
| Navigation In Use | Other |
| Flight Phase | cruise other |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | government : faa |
| Function | controller : radar |
| Qualification | controller : non radar |
| Experience | controller non radar : 4 controller radar : 2 |
| ASRS Report | 169549 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : atp |
| Events | |
| Anomaly | conflict : airborne less severe non adherence : published procedure non adherence : required legal separation |
| Independent Detector | atc equipment other atc equipment : unspecified |
| Resolutory Action | controller : issued new clearance |
| Consequence | Other |
| Miss Distance | horizontal : 17400 vertical : 600 |
| Supplementary | |
| Primary Problem | ATC Human Performance |
| Air Traffic Incident | Operational Error |
Narrative:
I had an large transport inbound to sfo on the runway 28 profile descent when I noticed light transport traffic just east of the large transport. I amended the large transport's altitude to remain above the light transport, he never acknowledged and I went on to other duties. The conflict alert went off a couple of mins later which brought my attention back to the situation and my attempt to stop the large transport above the light transport failed resulting in 2.9 NM and 600' sep. I should have recognized the light transport traffic before clearing the large transport on the runway 28 profile descent.
Original NASA ASRS Text
Title: CTLR CLEARED THE LGT TO DESCEND WHICH RESULTED IN LESS THAN STANDARD SEPARATION WITH AN ACFT BELOW THE LGT.
Narrative: I HAD AN LGT INBND TO SFO ON THE RWY 28 PROFILE DSNT WHEN I NOTICED LTT TFC JUST E OF THE LGT. I AMENDED THE LGT'S ALT TO REMAIN ABOVE THE LTT, HE NEVER ACKNOWLEDGED AND I WENT ON TO OTHER DUTIES. THE CONFLICT ALERT WENT OFF A COUPLE OF MINS LATER WHICH BROUGHT MY ATTN BACK TO THE SITUATION AND MY ATTEMPT TO STOP THE LGT ABOVE THE LTT FAILED RESULTING IN 2.9 NM AND 600' SEP. I SHOULD HAVE RECOGNIZED THE LTT TFC BEFORE CLRING THE LGT ON THE RWY 28 PROFILE DSNT.
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.