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Attempting to accommodate coordination route altitude changes for a ZOB controller, the ZAU radar controller descends a B737 into conflict with a BA10, both aircraft proceeding into ZOB airspace. The ZAU controller does not recognize the situation until conflict alert activates.
| Attributes | |
| ACN | 415556 |
| Time | |
| Date | 199809 |
| Day | Wed |
| Local Time Of Day | 1201 To 1800 |
| Place | |
| Locale Reference | atc facility : fwa |
| State Reference | IN |
| Altitude | msl bound lower : 19000 msl bound upper : 19000 |
| Environment | |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | artcc : zau artcc : zob |
| Operator | common carrier : air carrier |
| Make Model Name | B737 Undifferentiated or Other Model |
| Operating Under FAR Part | Part 121 |
| Flight Phase | descent other |
| Route In Use | arrival other |
| Flight Plan | IFR |
| Aircraft 2 | |
| Operator | general aviation : corporate |
| Make Model Name | BAe 125 Series 1000 |
| Operating Under FAR Part | Part 91 |
| Navigation In Use | Other |
| Flight Phase | cruise other |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | government : faa |
| Function | controller : non radar |
| Qualification | controller : radar |
| Experience | controller radar : 10 |
| ASRS Report | 415556 |
| Person 2 | |
| Affiliation | government : faa |
| Function | controller : radar |
| Qualification | controller : radar |
| Events | |
| Anomaly | conflict : airborne less severe non adherence : published procedure non adherence : required legal separation other anomaly other |
| Independent Detector | atc equipment other atc equipment : unspecified |
| Resolutory Action | none taken : detected after the fact |
| Consequence | faa : investigated |
| Miss Distance | horizontal : 4200 vertical : 600 |
| Supplementary | |
| Primary Problem | ATC Human Performance |
| Air Traffic Incident | Inter Facility Coordination Failure Operational Error |
Narrative:
Aircraft #1 holding for ord over fwa. Aircraft #2 inbound to dtw. Aircraft #3 overflt at FL190 northwest of fwa going ene. ZOB called and requested aircraft #2 and all other dtw inbounds to descend to FL180. FL180 was unusable. Sector was busy and controller cleared aircraft #2 to 17000 ft to get below aircraft #3. Data blocks overlapping and other traffic concerns led to controller not noticing conflict until it had/was occurred/occurring. Normal procedures for dtw arrs are at FL210. ZOB needing the aircraft 3000 ft lower, or in this case 4000 ft lower, contributed some to the error. Holding due to WX at ord was a factor. If the WX was coming to ord, why were all of the aircraft let off the ground instead of putting a ground stop in effect? Staffing. Our area was short staffed and had 2 people call in sick. A handoff was not requested, but if it was, it would have taken a long time to find one. We had 7 sectors open. 6 with 2 people and a controller in charge instead of a supervisor.
Original NASA ASRS Text
Title: ATTEMPTING TO ACCOMMODATE COORD RTE ALT CHANGES FOR A ZOB CTLR, THE ZAU RADAR CTLR DSNDS A B737 INTO CONFLICT WITH A BA10, BOTH ACFT PROCEEDING INTO ZOB AIRSPACE. THE ZAU CTLR DOES NOT RECOGNIZE THE SIT UNTIL CONFLICT ALERT ACTIVATES.
Narrative: ACFT #1 HOLDING FOR ORD OVER FWA. ACFT #2 INBOUND TO DTW. ACFT #3 OVERFLT AT FL190 NW OF FWA GOING ENE. ZOB CALLED AND REQUESTED ACFT #2 AND ALL OTHER DTW INBOUNDS TO DSND TO FL180. FL180 WAS UNUSABLE. SECTOR WAS BUSY AND CTLR CLRED ACFT #2 TO 17000 FT TO GET BELOW ACFT #3. DATA BLOCKS OVERLAPPING AND OTHER TFC CONCERNS LED TO CTLR NOT NOTICING CONFLICT UNTIL IT HAD/WAS OCCURRED/OCCURRING. NORMAL PROCS FOR DTW ARRS ARE AT FL210. ZOB NEEDING THE ACFT 3000 FT LOWER, OR IN THIS CASE 4000 FT LOWER, CONTRIBUTED SOME TO THE ERROR. HOLDING DUE TO WX AT ORD WAS A FACTOR. IF THE WX WAS COMING TO ORD, WHY WERE ALL OF THE ACFT LET OFF THE GND INSTEAD OF PUTTING A GND STOP IN EFFECT? STAFFING. OUR AREA WAS SHORT STAFFED AND HAD 2 PEOPLE CALL IN SICK. A HDOF WAS NOT REQUESTED, BUT IF IT WAS, IT WOULD HAVE TAKEN A LONG TIME TO FIND ONE. WE HAD 7 SECTORS OPEN. 6 WITH 2 PEOPLE AND A CIC INSTEAD OF A SUPVR.
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.