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Tys approach controller apparently misjudged separation spacing between outgoing and incoming traffic. Outgoing DC9 took evasive TCASII maneuver as opposite direction aircraft descended to the outgoing aircraft's altitude. Aircraft were on separate frequencys.
| Attributes | |
| ACN | 409714 |
| Time | |
| Date | 199807 |
| Day | Fri |
| Local Time Of Day | 0601 To 1200 |
| Place | |
| Locale Reference | atc facility : tys |
| State Reference | TN |
| Altitude | msl bound lower : 8700 msl bound upper : 10000 |
| Environment | |
| Flight Conditions | VMC |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | artcc : ztl tracon : tys |
| Operator | common carrier : air carrier |
| Make Model Name | DC-9 Undifferentiated or Other Model |
| Operating Under FAR Part | Part 121 |
| Flight Phase | cruise other |
| Route In Use | departure other |
| Flight Plan | IFR |
| Aircraft 2 | |
| Operator | common carrier : air carrier |
| Make Model Name | DC-9 Undifferentiated or Other Model |
| Operating Under FAR Part | Part 121 |
| Flight Phase | descent other |
| Route In Use | arrival other |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Qualification | pilot : flight engineer pilot : atp |
| Experience | flight time last 90 days : 160 flight time total : 10000 flight time type : 3000 |
| ASRS Report | 409714 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : flight engineer pilot : atp |
| Experience | controller military : 4 controller radar : 31 |
| ASRS Report | 410153 |
| Events | |
| Anomaly | conflict : airborne less severe non adherence : published procedure non adherence : required legal separation other anomaly other |
| Independent Detector | aircraft equipment other aircraft equipment : unspecified other flight crewa |
| Resolutory Action | flight crew : took evasive action |
| Consequence | faa : investigated |
| Miss Distance | horizontal : 6000 vertical : 750 |
| Supplementary | |
| Primary Problem | ATC Human Performance |
| Air Traffic Incident | Operational Error |
Narrative:
We departed from tys on runway 23R at XA00. Departure clearance was runway heading and 5000 ft MSL. After departure contacted knoxville departure who cleared us 285 degree radial direct bna and 10000 ft MSL, we contacted ZTL prior to leveling off at 10000 ft. We were expecting a clearance for higher altitude but did not get one. Within a few moments a target appeared on TCASII at 11000 ft, 12 O'clock and 15 mi. The target then started a descent. At approximately 5 mi we got a TCASII alert commanding a descent. We vacated 10000 ft and turned right descending to 8700 ft MSL. The traffic had leveled off at 10000 ft. When we finally had a visual we saw a DC9 in a climbing right turn. We had gotten within 1 mi and 750 ft of the traffic. We then inquired to ZTL and they said they were not talking to the other DC9. He was on tys approach. Nobody at any time informed us of possible conflicting traffic. Supplemental information from acn 410153: ZTL advised us that they were investigating the problem.
Original NASA ASRS Text
Title: TYS APCH CTLR APPARENTLY MISJUDGED SEPARATION SPACING BTWN OUTGOING AND INCOMING TFC. OUTGOING DC9 TOOK EVASIVE TCASII MANEUVER AS OPPOSITE DIRECTION ACFT DSNDED TO THE OUTGOING ACFT'S ALT. ACFT WERE ON SEPARATE FREQS.
Narrative: WE DEPARTED FROM TYS ON RWY 23R AT XA00. DEP CLRNC WAS RWY HDG AND 5000 FT MSL. AFTER DEP CONTACTED KNOXVILLE DEP WHO CLRED US 285 DEG RADIAL DIRECT BNA AND 10000 FT MSL, WE CONTACTED ZTL PRIOR TO LEVELING OFF AT 10000 FT. WE WERE EXPECTING A CLRNC FOR HIGHER ALT BUT DID NOT GET ONE. WITHIN A FEW MOMENTS A TARGET APPEARED ON TCASII AT 11000 FT, 12 O'CLOCK AND 15 MI. THE TARGET THEN STARTED A DSCNT. AT APPROX 5 MI WE GOT A TCASII ALERT COMMANDING A DSCNT. WE VACATED 10000 FT AND TURNED R DSNDING TO 8700 FT MSL. THE TFC HAD LEVELED OFF AT 10000 FT. WHEN WE FINALLY HAD A VISUAL WE SAW A DC9 IN A CLBING R TURN. WE HAD GOTTEN WITHIN 1 MI AND 750 FT OF THE TFC. WE THEN INQUIRED TO ZTL AND THEY SAID THEY WERE NOT TALKING TO THE OTHER DC9. HE WAS ON TYS APCH. NOBODY AT ANY TIME INFORMED US OF POSSIBLE CONFLICTING TFC. SUPPLEMENTAL INFO FROM ACN 410153: ZTL ADVISED US THAT THEY WERE INVESTIGATING THE PROB.
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.