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Controller vectoring large transport during descent had less than standard separation with enroute small transport.
| Attributes | |
| ACN | 95588 |
| Time | |
| Date | 198810 |
| Day | Fri |
| Local Time Of Day | 1801 To 2400 |
| Place | |
| Locale Reference | atc facility : sea |
| State Reference | WA |
| Altitude | msl bound lower : 16400 msl bound upper : 17000 |
| Environment | |
| Flight Conditions | VMC |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | artcc : zse tower : mdw |
| Operator | common carrier : air carrier |
| Make Model Name | Large Transport, Low Wing, 3 Turbojet Eng |
| Flight Phase | descent other |
| Route In Use | enroute : on vectors enroute airway : zse |
| Flight Plan | IFR |
| Aircraft 2 | |
| Operator | common carrier : air taxi |
| Make Model Name | Small Transport, Low Wing, 2 Turboprop Eng |
| Flight Phase | cruise other |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | government : faa |
| Function | controller : radar |
| Qualification | controller : radar |
| Experience | controller radar : 17 |
| ASRS Report | 95588 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : atp |
| Events | |
| Anomaly | conflict : airborne less severe non adherence : required legal separation |
| Independent Detector | atc equipment other atc equipment : unspecified other controllera |
| Resolutory Action | other |
| Consequence | faa : investigated |
| Miss Distance | horizontal : 23400 vertical : 600 |
| Supplementary | |
| Primary Problem | ATC Human Performance |
| Air Traffic Incident | Operational Error |
Narrative:
Large transport X from geg to sea. Had one small transport Y eastbound at 17000', another just south of him about 10 mi climbing to FL230. Had large transport X expedite his descent, but had to turn him for the aircraft climbing to FL230. Knew when I turned him I would have to turn him again soon, just didn't do it soon enough. Evasive action by aircraft not required. Sector complexity added to this error. Callback conversation with reporter revealed the following: experienced controller working moderate to heavy traffic (18 aircraft) knew when he turned the large transport X that he would have to turn him again soon to keep sep with the small transport Y. Got distracted momentarily with other traffic and when he turned the large transport it was too late and sep was lost. Traffic advisory was given, but aircraft did not see each other. Proximity of traffic was 600' and 3.9 mi.
Original NASA ASRS Text
Title: CTLR VECTORING LGT DURING DESCENT HAD LESS THAN STANDARD SEPARATION WITH ENROUTE SMT.
Narrative: LGT X FROM GEG TO SEA. HAD ONE SMT Y EBND AT 17000', ANOTHER JUST S OF HIM ABOUT 10 MI CLBING TO FL230. HAD LGT X EXPEDITE HIS DSCNT, BUT HAD TO TURN HIM FOR THE ACFT CLBING TO FL230. KNEW WHEN I TURNED HIM I WOULD HAVE TO TURN HIM AGAIN SOON, JUST DIDN'T DO IT SOON ENOUGH. EVASIVE ACTION BY ACFT NOT REQUIRED. SECTOR COMPLEXITY ADDED TO THIS ERROR. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING: EXPERIENCED CTLR WORKING MODERATE TO HEAVY TFC (18 ACFT) KNEW WHEN HE TURNED THE LGT X THAT HE WOULD HAVE TO TURN HIM AGAIN SOON TO KEEP SEP WITH THE SMT Y. GOT DISTRACTED MOMENTARILY WITH OTHER TFC AND WHEN HE TURNED THE LGT IT WAS TOO LATE AND SEP WAS LOST. TFC ADVISORY WAS GIVEN, BUT ACFT DID NOT SEE EACH OTHER. PROX OF TFC WAS 600' AND 3.9 MI.
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.