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ZOB controller does not ensure vertical separation between 2 A320's cleared into holding at djb VORTAC.
| Attributes | |
| ACN | 429328 |
| Time | |
| Date | 199902 |
| Day | Fri |
| Local Time Of Day | 0601 To 1200 |
| Place | |
| Locale Reference | navaid : djb.vortac |
| State Reference | MI |
| Altitude | msl bound lower : 15300 msl bound upper : 16000 |
| Environment | |
| Flight Conditions | Mixed |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | artcc : zob.artcc |
| Operator | common carrier : air carrier |
| Make Model Name | A320 |
| Operating Under FAR Part | Part 121 |
| Navigation In Use | other vortac |
| Flight Phase | descent : holding descent : approach |
| Route In Use | arrival : holding pattern |
| Flight Plan | IFR |
| Aircraft 2 | |
| Controlling Facilities | artcc : zob.artcc |
| Operator | common carrier : air carrier |
| Make Model Name | A320 |
| Operating Under FAR Part | Part 121 |
| Navigation In Use | other vortac |
| Flight Phase | descent : holding descent : approach |
| Route In Use | arrival : holding pattern |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | government : faa |
| Function | controller : radar |
| Qualification | controller : radar |
| Experience | controller military : 11 controller radar : 13 |
| ASRS Report | 429328 |
| 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 other anomaly other |
| Independent Detector | atc equipment : conflict alert other controllera |
| Resolutory Action | none taken : detected after the fact |
| Consequence | faa : investigated |
| Miss Distance | horizontal : 2700 vertical : 700 |
| Supplementary | |
| Problem Areas | ATC Human Performance |
| Primary Problem | ATC Human Performance |
| Air Traffic Incident | Operational Error |
Narrative:
2 jets descending into dtw were issued holding instructions due to low visibility at the airport. First aircraft requested reduced speed to set up for holding. I approved reduction thinking I would maintain enough longitudinal separation until vertical separation took effect. Second aircraft got within 4.5 NM of first aircraft before 1000 ft vertical separation obtained. (First aircraft descended to +2000 ft was at 15300 when second aircraft reached 16000 ft, his assigned altitude.)
Original NASA ASRS Text
Title: ZOB CTLR DOES NOT ENSURE VERT SEPARATION BTWN 2 A320'S CLRED INTO HOLDING AT DJB VORTAC.
Narrative: 2 JETS DSNDING INTO DTW WERE ISSUED HOLDING INSTRUCTIONS DUE TO LOW VISIBILITY AT THE ARPT. FIRST ACFT REQUESTED REDUCED SPD TO SET UP FOR HOLDING. I APPROVED REDUCTION THINKING I WOULD MAINTAIN ENOUGH LONGITUDINAL SEPARATION UNTIL VERT SEPARATION TOOK EFFECT. SECOND ACFT GOT WITHIN 4.5 NM OF FIRST ACFT BEFORE 1000 FT VERT SEPARATION OBTAINED. (FIRST ACFT DSNDED TO +2000 FT WAS AT 15300 WHEN SECOND ACFT REACHED 16000 FT, HIS ASSIGNED ALT.)
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.