Air carrier has TCASII RA after TA. Responds, then traffic sighted.

Attributes
ACN	204134
Time
Date	199203
Day	Sun
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : omn
State Reference	FL
Altitude	msl bound lower : 17200 msl bound upper : 17500
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zjx
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Navigation In Use	Other Other
Flight Phase	descent other
Flight Plan	IFR
Aircraft 2
Make Model Name	Small Transport
Flight Phase	cruise other
Flight Plan	VFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 200 flight time total : 11000 flight time type : 200
ASRS Report	204134
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : commercial pilot : instrument
Experience	flight time last 90 days : 150 flight time total : 2200 flight time type : 250
ASRS Report	204143
Events
Anomaly	conflict : nmac other anomaly other
Independent Detector	aircraft equipment other aircraft equipment : unspecified other flight crewa
Resolutory Action	flight crew : took evasive action
Consequence	Other
Miss Distance	horizontal : 0 vertical : 300
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	other

Narrative:

Descending through 18300 ft with clearance to cross lamma intersection at 12000/250 KTS, ATC advised of VFR traffic level at 17500 ft 12 O'clock 4 mi. Simultaneously, TCASII issued RA of min 2100 FPM descent. Current descent rate was 2000 FPM. Rate of descent increased to approximately 3500 FPM. ATC (different controller's voice) called traffic at 12 O'clock less than 1 mi. Observed small transport-twin with wing tip tanks directly ahead slightly above our position. Aircraft passed directly above as we descended through 17200 ft. It is unknown if other aircraft was in contact with center, but I believe I remember another aircraft being given TA (possibly advising him of our position). Problem may have been caused by inexperienced controller or momentary distraction. Could have been avoided by vector/altitude change. Poor judgement was obviously used by ATC, if the conflicting traffic was known to them. Supplemental information from acn 204148: my first reaction/thought was to level off above the traffic. I'm not sure we could have done that at our altitude and descent rate when we got the call. TCASII commanded a descent soon after center advised us of the traffic. Without TCASII, the miss distance would have been much less than 300 ft.

Original NASA ASRS Text

Title: ACR HAS TCASII RA AFTER TA. RESPONDS, THEN TFC SIGHTED.

Narrative: DSNDING THROUGH 18300 FT WITH CLRNC TO CROSS LAMMA INTXN AT 12000/250 KTS, ATC ADVISED OF VFR TFC LEVEL AT 17500 FT 12 O'CLOCK 4 MI. SIMULTANEOUSLY, TCASII ISSUED RA OF MIN 2100 FPM DSCNT. CURRENT DSCNT RATE WAS 2000 FPM. RATE OF DSCNT INCREASED TO APPROX 3500 FPM. ATC (DIFFERENT CTLR'S VOICE) CALLED TFC AT 12 O'CLOCK LESS THAN 1 MI. OBSERVED SMT-TWIN WITH WING TIP TANKS DIRECTLY AHEAD SLIGHTLY ABOVE OUR POS. ACFT PASSED DIRECTLY ABOVE AS WE DSNDED THROUGH 17200 FT. IT IS UNKNOWN IF OTHER ACFT WAS IN CONTACT WITH CTR, BUT I BELIEVE I REMEMBER ANOTHER ACFT BEING GIVEN TA (POSSIBLY ADVISING HIM OF OUR POS). PROBLEM MAY HAVE BEEN CAUSED BY INEXPERIENCED CTLR OR MOMENTARY DISTR. COULD HAVE BEEN AVOIDED BY VECTOR/ALT CHANGE. POOR JUDGEMENT WAS OBVIOUSLY USED BY ATC, IF THE CONFLICTING TFC WAS KNOWN TO THEM. SUPPLEMENTAL INFO FROM ACN 204148: MY FIRST REACTION/THOUGHT WAS TO LEVEL OFF ABOVE THE TFC. I'M NOT SURE WE COULD HAVE DONE THAT AT OUR ALT AND DSCNT RATE WHEN WE GOT THE CALL. TCASII COMMANDED A DSCNT SOON AFTER CTR ADVISED US OF THE TFC. WITHOUT TCASII, THE MISS DISTANCE WOULD HAVE BEEN MUCH LESS THAN 300 FT.

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.