MD80 descending for sjc experienced TCASII RA with ATC issued traffic.

Attributes
ACN	585376
Time
Date	200306
Day	Wed
Local Time Of Day	1201 To 1800
Place
Locale Reference	intersection : gilro
State Reference	CA
Altitude	msl bound lower : 10200 msl bound upper : 10600
Aircraft 1
Controlling Facilities	tracon : nct.tracon
Operator	common carrier : air carrier
Make Model Name	B757 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	descent : intermediate altitude
Flight Plan	IFR
Aircraft 2
Operator	general aviation : personal
Make Model Name	Small Aircraft
Operating Under FAR Part	Part 91
Flight Phase	cruise : level cruise : enroute altitude change
Flight Plan	None
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
ASRS Report	585376
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Events
Anomaly	conflict : airborne less severe non adherence : required legal separation
Independent Detector	aircraft equipment : tcas other controllera
Resolutory Action	controller : issued advisory flight crew : returned to assigned altitude flight crew : took precautionary avoidance action
Miss Distance	horizontal : 0 vertical : 500
Supplementary
Problem Areas	Flight Crew Human Performance
Primary Problem	Flight Crew Human Performance

Narrative:

ATC facility: bay approach. Location: inbound on sjc runway 30L localizer near gilro intersection descent to 10000 ft with bay -- bay advised us of VFR traffic at 1-2 O'clock position at 9500 ft. Our altitude was about 10600 ft in descent when we got call. Radio congestion existed and call was acknowledged. Saw VFR aircraft on TCASII got RA at about an altitude of 10200 ft. Did not see traffic. Started a climb. As climb started, saw VFR aircraft very close to us with a vertical separation of about 500-600 ft. Stopped climb at about 10600 ft and descended back to 10000 ft after VFR aircraft passed under. Never received a TA.

Original NASA ASRS Text

Title: MD80 DSNDING FOR SJC EXPERIENCED TCASII RA WITH ATC ISSUED TFC.

Narrative: ATC FACILITY: BAY APCH. LOCATION: INBOUND ON SJC RWY 30L LOC NEAR GILRO INTXN DSCNT TO 10000 FT WITH BAY -- BAY ADVISED US OF VFR TFC AT 1-2 O'CLOCK POS AT 9500 FT. OUR ALT WAS ABOUT 10600 FT IN DSCNT WHEN WE GOT CALL. RADIO CONGESTION EXISTED AND CALL WAS ACKNOWLEDGED. SAW VFR ACFT ON TCASII GOT RA AT ABOUT AN ALT OF 10200 FT. DID NOT SEE TFC. STARTED A CLB. AS CLB STARTED, SAW VFR ACFT VERY CLOSE TO US WITH A VERT SEPARATION OF ABOUT 500-600 FT. STOPPED CLB AT ABOUT 10600 FT AND DSNDED BACK TO 10000 FT AFTER VFR ACFT PASSED UNDER. NEVER RECEIVED A TA.

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.