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ZOB controller descends 2 air carrier's down to same altitude when issuing holding instructions for cle airport.
| Attributes | |
| ACN | 470465 |
| Time | |
| Date | 200004 |
| Day | Fri |
| Local Time Of Day | 0601 To 1200 |
| Place | |
| Locale Reference | navaid : cxr.vor |
| State Reference | OH |
| Altitude | msl single value : 10000 |
| Environment | |
| Flight Conditions | VMC |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | artcc : zob.artcc |
| Operator | common carrier : air carrier |
| Make Model Name | EMB ERJ 145 ER&LR |
| Operating Under FAR Part | Part 121 |
| Navigation In Use | other |
| Flight Phase | descent : approach descent : holding |
| Route In Use | arrival : holding pattern |
| Flight Plan | IFR |
| Aircraft 2 | |
| Controlling Facilities | artcc : zob.artcc |
| 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 | 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 radar : 12 controller time certified in position1 : 5 |
| ASRS Report | 470465 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : atp |
| Events | |
| Anomaly | conflict : airborne critical non adherence : published procedure non adherence : required legal separation |
| Independent Detector | atc equipment : conflict alert other controllera other flight crewa other flight crewb |
| Resolutory Action | controller : issued new clearance flight crew : took evasive action |
| Consequence | faa : investigated |
| Miss Distance | horizontal : 3000 vertical : 600 |
| Supplementary | |
| Problem Areas | Airspace Structure ATC Human Performance |
| Primary Problem | ATC Human Performance |
| Air Traffic Incident | Operational Error |
Narrative:
Was working an arrival sector handing off planes to cle approach. Had just finished up an arrival push, sector had slowed down and went to just radar controller. Approximately 5 aircraft on frequency. 2 aircraft were inbound to cle over the arrival fix -- both about 20 mi apart and cleared to cross the fix at 10000 ft and 250 KTS. Cle approach called and placed me in the hold. Both aircraft were issued holding instructions. I thought that the E145 (aircraft X), the second aircraft in the line, had been reclred by me to maintain 11000 ft. I changed that aircraft's data block to reflect that. The E145 never received that clearance however, and it descended down to 10000 ft, head-on with the MD80 (aircraft Y) which was established in the hold. I questioned the E145 about his altitude, and when he said level at 10000 ft, I tried to issue altitudes to both aircraft. The TCASII had already issued an RA at this point. Do not change a data block until the pilot has received the clearance of the altitude.
Original NASA ASRS Text
Title: ZOB CTLR DSNDS 2 ACR'S DOWN TO SAME ALT WHEN ISSUING HOLDING INSTRUCTIONS FOR CLE ARPT.
Narrative: WAS WORKING AN ARR SECTOR HANDING OFF PLANES TO CLE APCH. HAD JUST FINISHED UP AN ARR PUSH, SECTOR HAD SLOWED DOWN AND WENT TO JUST RADAR CTLR. APPROX 5 ACFT ON FREQ. 2 ACFT WERE INBOUND TO CLE OVER THE ARR FIX -- BOTH ABOUT 20 MI APART AND CLRED TO CROSS THE FIX AT 10000 FT AND 250 KTS. CLE APCH CALLED AND PLACED ME IN THE HOLD. BOTH ACFT WERE ISSUED HOLDING INSTRUCTIONS. I THOUGHT THAT THE E145 (ACFT X), THE SECOND ACFT IN THE LINE, HAD BEEN RECLRED BY ME TO MAINTAIN 11000 FT. I CHANGED THAT ACFT'S DATA BLOCK TO REFLECT THAT. THE E145 NEVER RECEIVED THAT CLRNC HOWEVER, AND IT DSNDED DOWN TO 10000 FT, HEAD-ON WITH THE MD80 (ACFT Y) WHICH WAS ESTABLISHED IN THE HOLD. I QUESTIONED THE E145 ABOUT HIS ALT, AND WHEN HE SAID LEVEL AT 10000 FT, I TRIED TO ISSUE ALTS TO BOTH ACFT. THE TCASII HAD ALREADY ISSUED AN RA AT THIS POINT. DO NOT CHANGE A DATA BLOCK UNTIL THE PLT HAS RECEIVED THE CLRNC OF THE 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.