MD88 flight crew is issued TA regarding VFR traffic then received TA and RA on TCASII.

Attributes
ACN	337328
Time
Date	199605
Day	Thu
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : phx
State Reference	AZ
Altitude	msl bound lower : 18000 msl bound upper : 18000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zab tower : dca
Operator	common carrier : air carrier
Make Model Name	MD-88
Operating Under FAR Part	Part 121
Navigation In Use	Other Other
Flight Phase	descent other
Route In Use	arrival star : star
Flight Plan	IFR
Aircraft 2
Make Model Name	Cessna Stationair/Turbo Stationair 6
Operating Under FAR Part	Part 91
Flight Phase	cruise other
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp pilot : flight engineer
Experience	flight time last 90 days : 82 flight time total : 9100 flight time type : 82
ASRS Report	337328
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : commercial pilot : instrument
Events
Anomaly	conflict : nmac other anomaly other
Independent Detector	other controllera other flight crewa
Resolutory Action	flight crew : took evasive action
Consequence	Other
Miss Distance	horizontal : 0 vertical : 500
Supplementary
Primary Problem	Flight Crew Human Performance

Narrative:

Proceeding direct to sunss intersection with clearance to cross at 11000 ft MSL and 250 KTS. At approximately FL210 to FL200 in descent, ATC said we had VFR, C206 traffic at 11 O'clock, 12 NM. Asked if they were transponder equipped as they did not appear on TCASII screen. ATC said yes. Continuing descent just about to ask for traffic position when TCASII issued TA and ATC mentioned traffic. TA went to RA with advisory to shallow descent to 500 FPM or less. It was apparent to us, traffic was going to pass right underneath us. First officer turned aircraft away and leveled off. I advised ATC. TCASII indicated 500 ft. Never saw traffic other than on TCASII display.

Original NASA ASRS Text

Title: MD88 FLC IS ISSUED TA REGARDING VFR TFC THEN RECEIVED TA AND RA ON TCASII.

Narrative: PROCEEDING DIRECT TO SUNSS INTXN WITH CLRNC TO CROSS AT 11000 FT MSL AND 250 KTS. AT APPROX FL210 TO FL200 IN DSCNT, ATC SAID WE HAD VFR, C206 TFC AT 11 O'CLOCK, 12 NM. ASKED IF THEY WERE XPONDER EQUIPPED AS THEY DID NOT APPEAR ON TCASII SCREEN. ATC SAID YES. CONTINUING DSCNT JUST ABOUT TO ASK FOR TFC POS WHEN TCASII ISSUED TA AND ATC MENTIONED TFC. TA WENT TO RA WITH ADVISORY TO SHALLOW DSCNT TO 500 FPM OR LESS. IT WAS APPARENT TO US, TFC WAS GOING TO PASS RIGHT UNDERNEATH US. FO TURNED ACFT AWAY AND LEVELED OFF. I ADVISED ATC. TCASII INDICATED 500 FT. NEVER SAW TFC OTHER THAN ON TCASII DISPLAY.

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.