Aircraft during descent stops descent 2000 ft high because TCASII shows conflicting traffic.

Attributes
ACN	316013
Time
Date	199509
Day	Sat
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : hyp
State Reference	CA
Altitude	msl bound lower : 16000 msl bound upper : 18000
Aircraft 1
Controlling Facilities	artcc : zoa
Operator	common carrier : air carrier
Make Model Name	MD-80 Super 80
Operating Under FAR Part	Part 121
Navigation In Use	Other Other
Flight Phase	descent other
Route In Use	arrival other arrival star : star enroute other
Flight Plan	IFR
Aircraft 2
Operator	general aviation : corporate
Make Model Name	Conquest I/Conquest II
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
ASRS Report	316013
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : commercial pilot : instrument
Events
Anomaly	altitude deviation : undershoot non adherence : clearance non adherence : published procedure 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 : 500
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	other

Narrative:

Flying the el nido arrival into sjc descending through FL190 to cross pappi intersection at or below 16000 ft. At this time ZOA called traffic ahead, opposite direction, VFR 'conquest' at 17500 ft. Did not see him except on TCASII. Decided to abandon the descent and level at FL180. Told center we were no longer going to make pappi intersection at 16000 ft. As we leveled off at FL180, TCASII gave us an RA. TCASII did a perfect job. Saw the traffic as he passed under us. Closure rate was probably about 700 KTS. In the past, in similar sits, controllers have given us precautionary leveloff clrncs to keep us out of harm's way. This controller would have been doing a better job had he done so too. Sure, he had no obligation to separate us from VFR traffic, but see and avoid does not really work in this regime with such high closure rates. Thank you TCASII.

Original NASA ASRS Text

Title: ACFT DURING DSCNT STOPS DSCNT 2000 FT HIGH BECAUSE TCASII SHOWS CONFLICTING TFC.

Narrative: FLYING THE EL NIDO ARR INTO SJC DSNDING THROUGH FL190 TO CROSS PAPPI INTXN AT OR BELOW 16000 FT. AT THIS TIME ZOA CALLED TFC AHEAD, OPPOSITE DIRECTION, VFR 'CONQUEST' AT 17500 FT. DID NOT SEE HIM EXCEPT ON TCASII. DECIDED TO ABANDON THE DSCNT AND LEVEL AT FL180. TOLD CTR WE WERE NO LONGER GOING TO MAKE PAPPI INTXN AT 16000 FT. AS WE LEVELED OFF AT FL180, TCASII GAVE US AN RA. TCASII DID A PERFECT JOB. SAW THE TFC AS HE PASSED UNDER US. CLOSURE RATE WAS PROBABLY ABOUT 700 KTS. IN THE PAST, IN SIMILAR SITS, CTLRS HAVE GIVEN US PRECAUTIONARY LEVELOFF CLRNCS TO KEEP US OUT OF HARM'S WAY. THIS CTLR WOULD HAVE BEEN DOING A BETTER JOB HAD HE DONE SO TOO. SURE, HE HAD NO OBLIGATION TO SEPARATE US FROM VFR TFC, BUT SEE AND AVOID DOES NOT REALLY WORK IN THIS REGIME WITH SUCH HIGH CLOSURE RATES. THANK YOU TCASII.

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.