B757 flight crew follows TCASII RA while descending into sna.

Attributes
ACN	438617
Time
Date	199905
Day	Fri
Local Time Of Day	1201 To 1800
Place
Locale Reference	intersection : kayoh
State Reference	CA
Altitude	msl single value : 10000
Environment
Flight Conditions	VMC
Weather Elements	other
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : sct.tracon
Operator	common carrier : air carrier
Make Model Name	B757 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	descent : approach
Route In Use	arrival star : kayoh 3
Flight Plan	IFR
Aircraft 2
Controlling Facilities	tracon : sct.tracon
Operator	general aviation : personal
Make Model Name	Cessna 310/T310C
Operating Under FAR Part	Part 91
Flight Phase	cruise : level
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
ASRS Report	438617
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : commercial pilot : multi engine pilot : instrument
Events
Anomaly	conflict : airborne less severe non adherence : far
Independent Detector	aircraft equipment : tcas other controllera other flight crewa other flight crewb
Resolutory Action	controller : issued advisory flight crew : returned to original clearance flight crew : took precautionary avoidance action
Miss Distance	vertical : 600
Supplementary
Problem Areas	ATC Human Performance Airspace Structure
Primary Problem	ATC Human Performance
Air Traffic Incident	Operational Error

Narrative:

Captain flying, on descent east of kayoh intersection ATC advised of unknown traffic 2 NM west of us, co-altitude. At the same time, TCASII directed a climb RA. We reversed to a 2500 FPM climb and soon after got a monitor vertical speed indication. Target was sighted crossing right to left about 600 ft below us. The cessna, I believe it was a C310, never alerted flight path. After clear of traffic, we descended back to 10000 ft and continued the arrival. Although WX at the time was hazy and sun in our 12 O'clock position, we were able to get a visual on the traffic due to its proximity. ATC advisory preceded RA by approximately 2-3 seconds.

Original NASA ASRS Text

Title: B757 FLC FOLLOWS TCASII RA WHILE DSNDING INTO SNA.

Narrative: CAPT FLYING, ON DSCNT E OF KAYOH INTXN ATC ADVISED OF UNKNOWN TFC 2 NM W OF US, CO-ALT. AT THE SAME TIME, TCASII DIRECTED A CLB RA. WE REVERSED TO A 2500 FPM CLB AND SOON AFTER GOT A MONITOR VERT SPD INDICATION. TARGET WAS SIGHTED XING R TO L ABOUT 600 FT BELOW US. THE CESSNA, I BELIEVE IT WAS A C310, NEVER ALERTED FLT PATH. AFTER CLR OF TFC, WE DSNDED BACK TO 10000 FT AND CONTINUED THE ARR. ALTHOUGH WX AT THE TIME WAS HAZY AND SUN IN OUR 12 O'CLOCK POS, WE WERE ABLE TO GET A VISUAL ON THE TFC DUE TO ITS PROX. ATC ADVISORY PRECEDED RA BY APPROX 2-3 SECONDS.

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.