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Aircraft was descended to a lower altitude and separation was lost with an aircraft in front and below the descending aircraft.
| Attributes | |
| ACN | 151088 |
| Time | |
| Date | 199007 |
| Day | Thu |
| Local Time Of Day | 1201 To 1800 |
| Place | |
| Locale Reference | atc facility : flo |
| State Reference | SC |
| Altitude | msl bound lower : 26000 msl bound upper : 26500 |
| Environment | |
| Flight Conditions | VMC |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | artcc : zjx tower : mci |
| Operator | general aviation : corporate |
| Make Model Name | Small Transport, Low Wing, 2 Turbojet Eng |
| Flight Phase | descent other |
| Flight Plan | IFR |
| Aircraft 2 | |
| Operator | other |
| Make Model Name | Military Trainer |
| Flight Phase | cruise other |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | government : faa |
| Function | controller : radar |
| Qualification | controller : radar |
| Experience | controller non radar : 2 controller radar : 22 |
| ASRS Report | 151088 |
| Person 2 | |
| Affiliation | Other |
| Function | oversight : pic |
| Qualification | pilot : commercial pilot : instrument |
| Events | |
| Anomaly | conflict : airborne less severe non adherence : published procedure non adherence : required legal separation |
| Independent Detector | atc equipment other atc equipment : unspecified |
| Resolutory Action | controller : issued new clearance |
| Consequence | faa : investigated |
| Miss Distance | horizontal : 9000 vertical : 500 |
| Supplementary | |
| Primary Problem | ATC Human Performance |
| Air Traffic Incident | Operational Error |
Narrative:
Small transport checked in with R48 descending to FL280. Shortly after that MTR checked in level at FL260. Small transport was landing chs and was overtaking MTR by 50-60 KTS. I descended small transport to FL270 but put FL240 (T) in the data block. As small transport was descending he questioned if I had traffic. Since I knew small transport was stopped at FL270, I immediately started looking for unknown aircraft. I restated to small transport to maintain FL270 and he acknowledged FL270. Conflict alert activated, but I knew it was mode C for the 2 aircraft were separated. When the satcs mr xx questioned me I stated it was mode C. I then put the 5 mi circle on MTR and turned MTR 20 degree left to get small transport started down to FL240 and handed off to R52. I then switched small transport to R52 and put MTR back on course direct chs.
Original NASA ASRS Text
Title: ACFT WAS DESCENDED TO A LOWER ALT AND SEPARATION WAS LOST WITH AN ACFT IN FRONT AND BELOW THE DESCENDING ACFT.
Narrative: SMT CHKED IN WITH R48 DSNDING TO FL280. SHORTLY AFTER THAT MTR CHKED IN LEVEL AT FL260. SMT WAS LNDG CHS AND WAS OVERTAKING MTR BY 50-60 KTS. I DSNDED SMT TO FL270 BUT PUT FL240 (T) IN THE DATA BLOCK. AS SMT WAS DSNDING HE QUESTIONED IF I HAD TFC. SINCE I KNEW SMT WAS STOPPED AT FL270, I IMMEDIATELY STARTED LOOKING FOR UNKNOWN ACFT. I RESTATED TO SMT TO MAINTAIN FL270 AND HE ACKNOWLEDGED FL270. CONFLICT ALERT ACTIVATED, BUT I KNEW IT WAS MODE C FOR THE 2 ACFT WERE SEPARATED. WHEN THE SATCS MR XX QUESTIONED ME I STATED IT WAS MODE C. I THEN PUT THE 5 MI CIRCLE ON MTR AND TURNED MTR 20 DEG L TO GET SMT STARTED DOWN TO FL240 AND HANDED OFF TO R52. I THEN SWITCHED SMT TO R52 AND PUT MTR BACK ON COURSE DIRECT CHS.
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.