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The controller issued aircraft X a descent clearance from FL350 to FL310 and a heading of 005 degrees for traffic. During the descent, aircraft X took evasive action to avoid aircraft Y converging at FL330.
| Attributes | |
| ACN | 427532 |
| Time | |
| Date | 199902 |
| Day | Thu |
| Local Time Of Day | 1201 To 1800 |
| Place | |
| Locale Reference | navaid : loz.vortac |
| State Reference | KY |
| Altitude | msl bound lower : 31000 msl bound upper : 34000 |
| Environment | |
| Flight Conditions | VMC |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | artcc : ztl.artcc tower : isp |
| Operator | common carrier : air carrier |
| Make Model Name | Commercial Fixed Wing |
| Operating Under FAR Part | Part 121 |
| Navigation In Use | other vortac |
| Flight Phase | cruise : enroute altitude change cruise : level |
| Route In Use | enroute : on vectors |
| Flight Plan | IFR |
| Aircraft 2 | |
| Controlling Facilities | artcc : ztl.artcc |
| Make Model Name | Commercial Fixed Wing |
| Flight Phase | cruise : level |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Qualification | pilot : multi engine pilot : flight engineer pilot : atp |
| Experience | flight time last 90 days : 150 flight time total : 8000 flight time type : 500 |
| ASRS Report | 427532 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain |
| Qualification | pilot : multi engine pilot : flight engineer pilot : atp |
| Experience | flight time last 90 days : 160 flight time total : 13400 flight time type : 7100 |
| ASRS Report | 427525 |
| Events | |
| Anomaly | conflict : airborne less severe non adherence : published procedure non adherence : required legal separation |
| Independent Detector | aircraft equipment : tcas |
| Resolutory Action | controller : issued new clearance flight crew : took evasive action |
| Miss Distance | horizontal : 18000 vertical : 1000 |
| Supplementary | |
| Problem Areas | ATC Human Performance |
| Primary Problem | ATC Human Performance |
| Air Traffic Incident | Operational Error |
Narrative:
We were at FL350 on an assigned heading of 005 degrees for traffic. We were then cleared to descend to FL310 for traffic. Approaching FL340 our TCASII announced 'reduce descent' for traffic about 2 O'clock and at FL330. ZTL then gave us a heading of 330 degrees and told us to expedite descent to FL310. We turned to FL330 but stopped the descent at FL340 for traffic below at FL330. After the TCASII announced 'clear of conflict,' we continued our descent to FL310 and ZTL turned us further left to a heading of 310 degrees. We continued on our flight without further incident. The controller's request to expedite descent was a poor one due to the lack of separation between our aircraft and the one below at FL330.
Original NASA ASRS Text
Title: THE CTLR ISSUED ACFT X A DSCNT CLRNC FROM FL350 TO FL310 AND A HDG OF 005 DEGS FOR TFC. DURING THE DSCNT, ACFT X TOOK EVASIVE ACTION TO AVOID ACFT Y CONVERGING AT FL330.
Narrative: WE WERE AT FL350 ON AN ASSIGNED HDG OF 005 DEGS FOR TFC. WE WERE THEN CLRED TO DSND TO FL310 FOR TFC. APCHING FL340 OUR TCASII ANNOUNCED 'REDUCE DSCNT' FOR TFC ABOUT 2 O'CLOCK AND AT FL330. ZTL THEN GAVE US A HDG OF 330 DEGS AND TOLD US TO EXPEDITE DSCNT TO FL310. WE TURNED TO FL330 BUT STOPPED THE DSCNT AT FL340 FOR TFC BELOW AT FL330. AFTER THE TCASII ANNOUNCED 'CLR OF CONFLICT,' WE CONTINUED OUR DSCNT TO FL310 AND ZTL TURNED US FURTHER L TO A HDG OF 310 DEGS. WE CONTINUED ON OUR FLT WITHOUT FURTHER INCIDENT. THE CTLR'S REQUEST TO EXPEDITE DSCNT WAS A POOR ONE DUE TO THE LACK OF SEPARATION BTWN OUR ACFT AND THE ONE BELOW AT FL330.
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.