Large transport given TA, then cleared to descend, has TCASII RA.

Attributes
ACN	289859
Time
Date	199411
Day	Mon
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : sfo
State Reference	CA
Altitude	msl bound lower : 10500 msl bound upper : 11000
Environment
Flight Conditions	VMC
Light	Night
Aircraft 1
Controlling Facilities	tracon : oak
Operator	common carrier : air carrier
Make Model Name	Commercial Fixed Wing
Operating Under FAR Part	Part 121
Flight Phase	descent other
Route In Use	arrival other enroute : on vectors
Flight Plan	IFR
Aircraft 2
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Operating Under FAR Part	other : unknown
Flight Phase	cruise other
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : commercial pilot : instrument pilot : flight engineer pilot : atp
Experience	flight time last 90 days : 210 flight time total : 15000 flight time type : 5000
ASRS Report	289859
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : instrument pilot : commercial pilot : atp
Events
Anomaly	conflict : airborne less severe other anomaly other
Independent Detector	aircraft equipment other aircraft equipment : unspecified other controllera
Resolutory Action	flight crew : took evasive action
Consequence	faa : reviewed incident with flight crew
Miss Distance	horizontal : 3000 vertical : 500
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	other

Narrative:

After passing cedes intersection we were on a radar vector for sfo at 11000 ft. The controller gave a TA of target at about 11 O'clock and 3 mi at 10500 ft. We acknowledged the advisory but did not report traffic in sight. We were not told the direction of flight of the target. At about this time we were given a descent clearance and the copilot (PF) started down. I immediately expressed my reservations and the so and I spotted the traffic visually on a converging course. I told the controller we'd stop our descent and at about that time we got a TCASII RA to climb. The copilot climbed, we told ATC of receiving a TCASII RA, and the traffic passed in front of and below us. I feel the controller should have done 2 things differently: 1) tell us more information about the traffic including heading and if he was in radio contact. 2) he should have restr or at least suggested restricting our descent until we had the traffic in sight or had passed it. I realize if the traffic is VFR the controller may pass us through his altitude, but it seems reasonable to provide as much information as possible to avoid getting an RA. We contributed to the conflict by starting a descent without having traffic positively in sight. We incorrectly assumed traffic was not on a converging course.

Original NASA ASRS Text

Title: LGT GIVEN TA, THEN CLRED TO DSND, HAS TCASII RA.

Narrative: AFTER PASSING CEDES INTXN WE WERE ON A RADAR VECTOR FOR SFO AT 11000 FT. THE CTLR GAVE A TA OF TARGET AT ABOUT 11 O'CLOCK AND 3 MI AT 10500 FT. WE ACKNOWLEDGED THE ADVISORY BUT DID NOT RPT TFC IN SIGHT. WE WERE NOT TOLD THE DIRECTION OF FLT OF THE TARGET. AT ABOUT THIS TIME WE WERE GIVEN A DSCNT CLRNC AND THE COPLT (PF) STARTED DOWN. I IMMEDIATELY EXPRESSED MY RESERVATIONS AND THE SO AND I SPOTTED THE TFC VISUALLY ON A CONVERGING COURSE. I TOLD THE CTLR WE'D STOP OUR DSCNT AND AT ABOUT THAT TIME WE GOT A TCASII RA TO CLB. THE COPLT CLBED, WE TOLD ATC OF RECEIVING A TCASII RA, AND THE TFC PASSED IN FRONT OF AND BELOW US. I FEEL THE CTLR SHOULD HAVE DONE 2 THINGS DIFFERENTLY: 1) TELL US MORE INFO ABOUT THE TFC INCLUDING HDG AND IF HE WAS IN RADIO CONTACT. 2) HE SHOULD HAVE RESTR OR AT LEAST SUGGESTED RESTRICTING OUR DSCNT UNTIL WE HAD THE TFC IN SIGHT OR HAD PASSED IT. I REALIZE IF THE TFC IS VFR THE CTLR MAY PASS US THROUGH HIS ALT, BUT IT SEEMS REASONABLE TO PROVIDE AS MUCH INFO AS POSSIBLE TO AVOID GETTING AN RA. WE CONTRIBUTED TO THE CONFLICT BY STARTING A DSCNT WITHOUT HAVING TFC POSITIVELY IN SIGHT. WE INCORRECTLY ASSUMED TFC WAS NOT ON A CONVERGING COURSE.

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.