B757 air carrier aircraft on STAR descent receives TCASII RA and climbs to avoid traffic.

Attributes
ACN	378230
Time
Date	199708
Day	Sun
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : sna
State Reference	CA
Altitude	msl bound lower : 5100 msl bound upper : 5500
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : lax tower : sts
Operator	common carrier : air carrier
Make Model Name	B757 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Navigation In Use	Other Other
Flight Phase	descent other
Route In Use	arrival other arrival star : star enroute airway : lax
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 : atp
ASRS Report	378230
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : instrument pilot : commercial
Events
Anomaly	altitude deviation : excursion from assigned altitude conflict : airborne less severe other anomaly other
Independent Detector	other flight crewa
Resolutory Action	flight crew : took evasive action
Consequence	Other
Supplementary
Air Traffic Incident	other

Narrative:

During descent to 5100 ft on the eastside 2 arrival into sna we observed a TCASII TA of traffic below us. We saw a light aircraft at 12 O'clock position as the RA sounded. I advised socal approach we were climbing in response to an RA and that we had the light aircraft visually. Apparently socal approach had called to direct us to climb to avoid conflict as we began our climb. Xmissions from other aircraft and perhaps ours stepped on the controller's call to us because he told us he had called us twice. Concerning the inside the cockpit work and light aircraft should be directed to stay clear of this arrival. This traffic conflict was compounded because of the weekend and therefore more light aircraft flying. Even if we had not seen the light aircraft TCASII would have saved us from a midair collision.

Original NASA ASRS Text

Title: B757 ACR ACFT ON STAR DSCNT RECEIVES TCASII RA AND CLBS TO AVOID TFC.

Narrative: DURING DSCNT TO 5100 FT ON THE EASTSIDE 2 ARR INTO SNA WE OBSERVED A TCASII TA OF TFC BELOW US. WE SAW A LIGHT ACFT AT 12 O'CLOCK POS AS THE RA SOUNDED. I ADVISED SOCAL APCH WE WERE CLBING IN RESPONSE TO AN RA AND THAT WE HAD THE LIGHT ACFT VISUALLY. APPARENTLY SOCAL APCH HAD CALLED TO DIRECT US TO CLB TO AVOID CONFLICT AS WE BEGAN OUR CLB. XMISSIONS FROM OTHER ACFT AND PERHAPS OURS STEPPED ON THE CTLR'S CALL TO US BECAUSE HE TOLD US HE HAD CALLED US TWICE. CONCERNING THE INSIDE THE COCKPIT WORK AND LIGHT ACFT SHOULD BE DIRECTED TO STAY CLR OF THIS ARR. THIS TFC CONFLICT WAS COMPOUNDED BECAUSE OF THE WEEKEND AND THEREFORE MORE LIGHT ACFT FLYING. EVEN IF WE HAD NOT SEEN THE LIGHT ACFT TCASII WOULD HAVE SAVED US FROM A MIDAIR COLLISION.

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.