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37000 Feet | Browse and search NASA's Aviation Safety Reporting System |
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ARTCC radar controller who had just taken over the sector was alerted to a potential conflict less than standard separation occurrence by the conflict alert. An LR35 was descending through the altitude of an air carrier MD80 and there was insufficient time for the controller to intervene. The MD80 reacted to a TCASII alert and the controller who had just been relieved was unaware of the situation during his relief briefing. Flight progress strip sequencing and interfacility coordination also distraction the reporter.
| Attributes | |
| ACN | 374522 |
| Time | |
| Date | 199707 |
| Day | Fri |
| Local Time Of Day | 1201 To 1800 |
| Place | |
| Locale Reference | atc facility : boi |
| State Reference | ID |
| Altitude | msl bound lower : 33000 msl bound upper : 33000 |
| Environment | |
| Flight Conditions | VMC |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | artcc : zlc |
| Operator | common carrier : air carrier |
| Make Model Name | MD-80 Series (DC-9-80) Undifferentiated or Other Model |
| Operating Under FAR Part | Part 121 |
| Flight Phase | cruise other descent other |
| Flight Plan | IFR |
| Aircraft 2 | |
| Operator | general aviation : corporate |
| Make Model Name | Learjet 35 |
| Operating Under FAR Part | Part 91 |
| Flight Phase | descent other |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | government : faa |
| Function | controller : radar |
| Qualification | controller : radar pilot : private |
| Experience | controller non radar : 4 controller radar : 3 flight time total : 60 |
| ASRS Report | 374522 |
| Person 2 | |
| Affiliation | government : faa |
| Function | controller : radar |
| Qualification | controller : radar |
| Events | |
| Anomaly | conflict : airborne less severe non adherence : required legal separation |
| Independent Detector | atc equipment other atc equipment : unspecified aircraft equipment other aircraft equipment : unspecified |
| Resolutory Action | flight crew : took evasive action none taken : anomaly accepted |
| Consequence | Other |
| Miss Distance | horizontal : 8700 vertical : 800 |
| Supplementary | |
| Primary Problem | ATC Human Performance |
| Air Traffic Incident | Operational Error |
Narrative:
I plugged into sector R41 to relieve the radar controller. During the traffic portion of the relief briefing the controller said, 'nobody's on a heading right now, everybody's on their own, heading's been passed on that way (an air carrier).' I then asked if the air carrier was pointed out to sector 8. The relief briefing ended with him unplugging, saying yes, and walking away. At no point during the briefing did the controller reference either airplane involved in the incident. I then went to take care of another aircraft -- the pilot that called during the relief briefing. Approximately 1 min elapsed getting his request, updating the data block giving him a communication change, and verbally coordinating with sector 31. A B01 dinger pulled me over to the strips. I began dealing with the bay of recently delivered strips, shipped the air carrier, and answered another air carrier's check-on. While still on the strips, light transport Y called me out of FL350 descending to FL240. Thinking it was an initial check-on, I answered him while looking for his strip. Not finding his strip (it had already been pulled down), I answered seattle sector 16 who had called prior to light transport Y. While on the line to seattle, I noticed the conflict alert had activated. I quickly tried to climb light transport Y back up to FL350, but I hadn't successfully terminated my line with seattle. At this point I saw air carrier X descending on what I assumed to be a TCASII RA and I knew there was nothing else I could do that would allow for further separation. Any clearance I would have given at this point wouldn't have taken effect until after the airplanes had passed. All this took place in less than 2 mins of the other controller unplugging, and he was still in the control room so I called him back. I asked him about the 2 airplanes involved. He was as surprised as I was.
Original NASA ASRS Text
Title: ARTCC RADAR CTLR WHO HAD JUST TAKEN OVER THE SECTOR WAS ALERTED TO A POTENTIAL CONFLICT LTSS OCCURRENCE BY THE CONFLICT ALERT. AN LR35 WAS DSNDING THROUGH THE ALT OF AN ACR MD80 AND THERE WAS INSUFFICIENT TIME FOR THE CTLR TO INTERVENE. THE MD80 REACTED TO A TCASII ALERT AND THE CTLR WHO HAD JUST BEEN RELIEVED WAS UNAWARE OF THE SIT DURING HIS RELIEF BRIEFING. FLT PROGRESS STRIP SEQUENCING AND INTERFAC COORD ALSO DISTR THE RPTR.
Narrative: I PLUGGED INTO SECTOR R41 TO RELIEVE THE RADAR CTLR. DURING THE TFC PORTION OF THE RELIEF BRIEFING THE CTLR SAID, 'NOBODY'S ON A HDG RIGHT NOW, EVERYBODY'S ON THEIR OWN, HDG'S BEEN PASSED ON THAT WAY (AN ACR).' I THEN ASKED IF THE ACR WAS POINTED OUT TO SECTOR 8. THE RELIEF BRIEFING ENDED WITH HIM UNPLUGGING, SAYING YES, AND WALKING AWAY. AT NO POINT DURING THE BRIEFING DID THE CTLR REF EITHER AIRPLANE INVOLVED IN THE INCIDENT. I THEN WENT TO TAKE CARE OF ANOTHER ACFT -- THE PLT THAT CALLED DURING THE RELIEF BRIEFING. APPROX 1 MIN ELAPSED GETTING HIS REQUEST, UPDATING THE DATA BLOCK GIVING HIM A COM CHANGE, AND VERBALLY COORDINATING WITH SECTOR 31. A B01 DINGER PULLED ME OVER TO THE STRIPS. I BEGAN DEALING WITH THE BAY OF RECENTLY DELIVERED STRIPS, SHIPPED THE ACR, AND ANSWERED ANOTHER ACR'S CHK-ON. WHILE STILL ON THE STRIPS, LTT Y CALLED ME OUT OF FL350 DSNDING TO FL240. THINKING IT WAS AN INITIAL CHK-ON, I ANSWERED HIM WHILE LOOKING FOR HIS STRIP. NOT FINDING HIS STRIP (IT HAD ALREADY BEEN PULLED DOWN), I ANSWERED SEATTLE SECTOR 16 WHO HAD CALLED PRIOR TO LTT Y. WHILE ON THE LINE TO SEATTLE, I NOTICED THE CONFLICT ALERT HAD ACTIVATED. I QUICKLY TRIED TO CLB LTT Y BACK UP TO FL350, BUT I HADN'T SUCCESSFULLY TERMINATED MY LINE WITH SEATTLE. AT THIS POINT I SAW ACR X DSNDING ON WHAT I ASSUMED TO BE A TCASII RA AND I KNEW THERE WAS NOTHING ELSE I COULD DO THAT WOULD ALLOW FOR FURTHER SEPARATION. ANY CLRNC I WOULD HAVE GIVEN AT THIS POINT WOULDN'T HAVE TAKEN EFFECT UNTIL AFTER THE AIRPLANES HAD PASSED. ALL THIS TOOK PLACE IN LESS THAN 2 MINS OF THE OTHER CTLR UNPLUGGING, AND HE WAS STILL IN THE CTL ROOM SO I CALLED HIM BACK. I ASKED HIM ABOUT THE 2 AIRPLANES INVOLVED. HE WAS AS SURPRISED AS I WAS.
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.