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37000 Feet | Browse and search NASA's Aviation Safety Reporting System |
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ZAU controller experienced operational error at approximately 12000 ft when preceding aircraft slowed to an 'expected' airspeed and was overtaken by succeeding traffic.
| Attributes | |
| ACN | 717086 |
| Time | |
| Date | 200611 |
| Place | |
| Locale Reference | airport : ord.airport |
| State Reference | IL |
| Altitude | msl single value : 12000 |
| Environment | |
| Flight Conditions | Marginal |
| Aircraft 1 | |
| Controlling Facilities | artcc : zau.artcc |
| Operator | common carrier : air carrier |
| Make Model Name | B757-200 |
| Operating Under FAR Part | Part 121 |
| Flight Phase | descent : approach |
| Flight Plan | IFR |
| Aircraft 2 | |
| Controlling Facilities | artcc : zau.artcc |
| Operator | common carrier : air carrier |
| Make Model Name | EMB ERJ 145 ER&LR |
| Operating Under FAR Part | Part 121 |
| Flight Phase | descent : approach |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | government : faa |
| Function | controller : radar |
| Qualification | controller : radar |
| Experience | controller radar : 18 |
| ASRS Report | 717086 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Events | |
| Anomaly | conflict : airborne less severe non adherence : required legal separation |
| Independent Detector | atc equipment : conflict alert other controllera |
| Resolutory Action | controller : issued alert controller : issued new clearance flight crew : took evasive action |
| Consequence | faa : investigated |
| Miss Distance | horizontal : 27000 vertical : 300 |
| Supplementary | |
| Problem Areas | ATC Human Performance |
| Primary Problem | ATC Human Performance |
| Air Traffic Incident | Operational Error |
Narrative:
Air carrier X was given a descent clearance and told that he would need to be slowed to 210 KTS. Air carrier X took the 210 KTS as an actual clearance instead of an expect clearance when he got down. Air carrier X was caught from behind by a regional jet.
Original NASA ASRS Text
Title: ZAU CTLR EXPERIENCED OPERROR AT APPROX 12000 FT WHEN PRECEDING ACFT SLOWED TO AN 'EXPECTED' AIRSPD AND WAS OVERTAKEN BY SUCCEEDING TFC.
Narrative: ACR X WAS GIVEN A DSCNT CLRNC AND TOLD THAT HE WOULD NEED TO BE SLOWED TO 210 KTS. ACR X TOOK THE 210 KTS AS AN ACTUAL CLRNC INSTEAD OF AN EXPECT CLRNC WHEN HE GOT DOWN. ACR X WAS CAUGHT FROM BEHIND BY A REGIONAL JET.
Data retrieved from NASA's ASRS site as of January 2009 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.