Narrative:

Near midair collision. Level at 10000 ft, inbound to smo, TCASII gave a yellow traffic alert. Traffic was climbing and was 400 ft above our altitude at the 12:30 O'clock position and about 5 mi and moving towards 1 O'clock. ATC gave traffic alert company aircraft climbed above their altitude on the gorman departure and is starting back down. I knew that is 9000 ft from past experience. TCASII issued a small descent rate. I started that. I visually picked up the aircraft. They were now descending at a rapid rate. TCASII wanted us to descend faster. That would have put us right into the aircraft. I turned to avoid the aircraft. We were at 9500 ft and about 1 mi away when we avoided the aircraft. I climbed back to 10000 ft and continued the arrival. ATC gave us a handoff and said thank you to us. A few passenger saw the aircraft and made comments about it as they deplaned. That was pretty close and a little exciting and thank you for that turn. I believe at the rate things happened TCASII could not give the correct information for the rapidly changing situation. Supplemental information from acn 515157: location: smo 261 degree radial, 14 DME. During turn in on the saade arrival, we received a call from ATC about a traffic alert and at the same time we received a TCASII traffic alert. The controller began to issue instructions. The RA was commanding a descent of 2500 FPM and the PF acquired the target visually. The captain acting as PF maneuvered the airplane laterally to the right to get the target moving across the windscreen. The RA was commanding a descent which if followed would have made the encounter worse. We were at 10000 ft and the target aircraft was descending through our altitude. The target aircraft passed within 1 mi of our aircraft.

Google
 

Original NASA ASRS Text

Title: MD80 CREW HAD TCASII RA WITH COMPANY ACFT IN SCT CLASS B AIRSPACE.

Narrative: NMAC. LEVEL AT 10000 FT, INBOUND TO SMO, TCASII GAVE A YELLOW TFC ALERT. TFC WAS CLBING AND WAS 400 FT ABOVE OUR ALT AT THE 12:30 O'CLOCK POS AND ABOUT 5 MI AND MOVING TOWARDS 1 O'CLOCK. ATC GAVE TFC ALERT COMPANY ACFT CLBED ABOVE THEIR ALT ON THE GORMAN DEP AND IS STARTING BACK DOWN. I KNEW THAT IS 9000 FT FROM PAST EXPERIENCE. TCASII ISSUED A SMALL DSCNT RATE. I STARTED THAT. I VISUALLY PICKED UP THE ACFT. THEY WERE NOW DSNDING AT A RAPID RATE. TCASII WANTED US TO DSND FASTER. THAT WOULD HAVE PUT US RIGHT INTO THE ACFT. I TURNED TO AVOID THE ACFT. WE WERE AT 9500 FT AND ABOUT 1 MI AWAY WHEN WE AVOIDED THE ACFT. I CLBED BACK TO 10000 FT AND CONTINUED THE ARR. ATC GAVE US A HDOF AND SAID THANK YOU TO US. A FEW PAX SAW THE ACFT AND MADE COMMENTS ABOUT IT AS THEY DEPLANED. THAT WAS PRETTY CLOSE AND A LITTLE EXCITING AND THANK YOU FOR THAT TURN. I BELIEVE AT THE RATE THINGS HAPPENED TCASII COULD NOT GIVE THE CORRECT INFO FOR THE RAPIDLY CHANGING SIT. SUPPLEMENTAL INFO FROM ACN 515157: LOCATION: SMO 261 DEG RADIAL, 14 DME. DURING TURN IN ON THE SAADE ARR, WE RECEIVED A CALL FROM ATC ABOUT A TFC ALERT AND AT THE SAME TIME WE RECEIVED A TCASII TFC ALERT. THE CTLR BEGAN TO ISSUE INSTRUCTIONS. THE RA WAS COMMANDING A DSCNT OF 2500 FPM AND THE PF ACQUIRED THE TARGET VISUALLY. THE CAPT ACTING AS PF MANEUVERED THE AIRPLANE LATERALLY TO THE R TO GET THE TARGET MOVING ACROSS THE WINDSCREEN. THE RA WAS COMMANDING A DSCNT WHICH IF FOLLOWED WOULD HAVE MADE THE ENCOUNTER WORSE. WE WERE AT 10000 FT AND THE TARGET ACFT WAS DSNDING THROUGH OUR ALT. THE TARGET ACFT PASSED WITHIN 1 MI OF OUR ACFT.

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.