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A B737-800 air carrier enters a holding pattern at FL310 and receives a TCAS RA for another aircraft near the same altitude. ATC then issued a descent to FL290; however; not before a loss of separation occurred.
| Attributes | |
| ACN | 687444 |
| Time | |
| Date | 200602 |
| Local Time Of Day | 0601 To 1200 |
| Place | |
| Locale Reference | intersection : macey |
| State Reference | GA |
| Altitude | msl bound lower : 29000 msl bound upper : 31000 |
| Environment | |
| Flight Conditions | VMC |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | artcc : ztl.artcc |
| Operator | common carrier : air carrier |
| Make Model Name | B737-800 |
| Operating Under FAR Part | Part 121 |
| Flight Phase | cruise : holding |
| Flight Plan | IFR |
| Aircraft 2 | |
| Controlling Facilities | artcc : ztl.artcc |
| Operator | common carrier : air carrier |
| Make Model Name | Canadair/Bombardier Undifferentiated or Other Model |
| Operating Under FAR Part | Part 121 |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Qualification | pilot : atp |
| Experience | flight time last 90 days : 200 flight time total : 9000 flight time type : 700 |
| ASRS Report | 687444 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : atp |
| Experience | flight time last 90 days : 240 flight time total : 9000 flight time type : 3000 |
| ASRS Report | 687438 |
| Events | |
| Anomaly | conflict : airborne critical non adherence : required legal separation non adherence : published procedure |
| Independent Detector | aircraft equipment : tcas |
| Resolutory Action | controller : issued new clearance |
| Supplementary | |
| Problem Areas | ATC Human Performance |
| Primary Problem | ATC Human Performance |
| Air Traffic Incident | Operational Error |
Narrative:
On the arrival into atlanta; we were given holding at macey in the depicted pattern. On the second trip outbound; the TCAS alert activated. Shortly after which ZTL told us to descend to FL290. We visually acquired the other aircraft and as we began the descent the RA went off. Closest distance was approximately 3 NM and we were level initially but quickly acquired vertical separation. Contributing factors in this event were severe communications load on ATC due to all the aircraft being in this holding pattern. ATC appeared to be task saturated with similar call signs; making several mistakes. We believe we did not miss an altitude change.
Original NASA ASRS Text
Title: A B737-800 ACR ENTERS A HOLDING PATTERN AT FL310 AND RECEIVES A TCAS RA FOR ANOTHER ACFT NEAR THE SAME ALT. ATC THEN ISSUED A DSCNT TO FL290; HOWEVER; NOT BEFORE A LOSS OF SEPARATION OCCURRED.
Narrative: ON THE ARR INTO ATLANTA; WE WERE GIVEN HOLDING AT MACEY IN THE DEPICTED PATTERN. ON THE SECOND TRIP OUTBOUND; THE TCAS ALERT ACTIVATED. SHORTLY AFTER WHICH ZTL TOLD US TO DSND TO FL290. WE VISUALLY ACQUIRED THE OTHER ACFT AND AS WE BEGAN THE DSCNT THE RA WENT OFF. CLOSEST DISTANCE WAS APPROX 3 NM AND WE WERE LEVEL INITIALLY BUT QUICKLY ACQUIRED VERT SEPARATION. CONTRIBUTING FACTORS IN THIS EVENT WERE SEVERE COMS LOAD ON ATC DUE TO ALL THE ACFT BEING IN THIS HOLDING PATTERN. ATC APPEARED TO BE TASK SATURATED WITH SIMILAR CALL SIGNS; MAKING SEVERAL MISTAKES. WE BELIEVE WE DID NOT MISS AN ALT CHANGE.
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.