Air carrier descending as cleared has TCASII RA to climb.

Attributes
ACN	238973
Time
Date	199304
Day	Thu
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : sfo
State Reference	CA
Altitude	msl bound lower : 15500 msl bound upper : 16000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	Large Transport, Low Wing, 2 Turbojet Eng
Navigation In Use	Other Other
Flight Phase	descent : approach descent other climbout : takeoff
Route In Use	arrival other arrival star : star enroute airway : zoa
Flight Plan	IFR
Aircraft 2
Operator	common carrier : air carrier
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : flight engineer pilot : atp
Experience	flight time last 90 days : 150 flight time total : 10000 flight time type : 1200
ASRS Report	238973
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp pilot : commercial pilot : instrument
Events
Anomaly	conflict : airborne less severe 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 : 1000
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

We were descending on the big sur arrival to sfo. As we approached anjee intersection at approximately 17000 ft, ZOA advised us of VFR traffic, an air carrier turboprop, opposite direction at 15500 ft. We saw the traffic on our TCASII display on the ehsi, but at no time did we make visual contact with the traffic. ZOA advised us that the traffic had us in sight. This was the only advisory ZOA gave us. It was clear to us from the TCASII display that there was going to be a conflict. Sure enough, as we descended through 16000 ft, we got an RA and a command to climb. We climbed back to 16500 and the traffic passed beneath us, although we never saw it. We advised ZOA, but got no response. If it had not been for TCASII, we may well have collided. Suggestion: it is not enough, in such a situation, for only 1 aircraft to have the other in sight. Both aircraft should have reported each other in sight, or ATC should have vectored us (the IFR traffic) around the VFR traffic.

Original NASA ASRS Text

Title: ACR DSNDING AS CLRED HAS TCASII RA TO CLB.

Narrative: WE WERE DSNDING ON THE BIG SUR ARR TO SFO. AS WE APCHED ANJEE INTXN AT APPROX 17000 FT, ZOA ADVISED US OF VFR TFC, AN ACR TURBOPROP, OPPOSITE DIRECTION AT 15500 FT. WE SAW THE TFC ON OUR TCASII DISPLAY ON THE EHSI, BUT AT NO TIME DID WE MAKE VISUAL CONTACT WITH THE TFC. ZOA ADVISED US THAT THE TFC HAD US IN SIGHT. THIS WAS THE ONLY ADVISORY ZOA GAVE US. IT WAS CLR TO US FROM THE TCASII DISPLAY THAT THERE WAS GOING TO BE A CONFLICT. SURE ENOUGH, AS WE DSNDED THROUGH 16000 FT, WE GOT AN RA AND A COMMAND TO CLB. WE CLBED BACK TO 16500 AND THE TFC PASSED BENEATH US, ALTHOUGH WE NEVER SAW IT. WE ADVISED ZOA, BUT GOT NO RESPONSE. IF IT HAD NOT BEEN FOR TCASII, WE MAY WELL HAVE COLLIDED. SUGGESTION: IT IS NOT ENOUGH, IN SUCH A SIT, FOR ONLY 1 ACFT TO HAVE THE OTHER IN SIGHT. BOTH ACFT SHOULD HAVE RPTED EACH OTHER IN SIGHT, OR ATC SHOULD HAVE VECTORED US (THE IFR TFC) AROUND THE VFR TFC.

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.