B737-700 experienced near midair collision on downwind at lax from an aircraft who was not talking t...

Attributes
ACN	1019945
Time
Date	201206
Local Time Of Day	0601-1200
Place
Locale Reference	LAX.Airport
State Reference	CA
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	B737-700
Operating Under FAR Part	Part 121
Flight Phase	Initial Approach
Flight Plan	IFR
Aircraft 2
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Person 1
Function	First Officer
Experience	Flight Crew Last 90 Days 218 Flight Crew Type 3670
Person 2
Function	Captain
Qualification	Flight Crew Air Transport Pilot (ATP)
Experience	Flight Crew Last 90 Days 227
Events
Anomaly	Conflict NMAC

Narrative:

While being vectored to a visual approach to runway 24R at lax and approximately 9 DME from the runway; we received a TCAS RA for pop up traffic at our 10-11 o'clock. We were vectored to our base turn from downwind by ATC as they became aware of the traffic conflict. Our aircraft was passing 3;300 ft in a descent to 3;000 ft when the RA was received. We executed a TCAS avoidance procedures as described in the fom; executing a level off to very slight climb in accordance with TCAS guidance. Audible 'adjust vertical speed' was issued by the TCAS system. System showed the nearest point of separation to be 400 ft. ATC advised us that conflict aircraft was 'not supposed to be there' and was apparently not in contact with them.

Original NASA ASRS Text

Title: B737-700 experienced NMAC on downwind at LAX from an aircraft who was not talking to ATC.

Narrative: While being vectored to a visual approach to Runway 24R at LAX and approximately 9 DME from the runway; we received a TCAS RA for pop up traffic at our 10-11 o'clock. We were vectored to our base turn from downwind by ATC as they became aware of the traffic conflict. Our aircraft was passing 3;300 FT in a descent to 3;000 FT when the RA was received. We executed a TCAS avoidance procedures as described in the FOM; executing a level off to very slight climb in accordance with TCAS guidance. Audible 'Adjust Vertical Speed' was issued by the TCAS system. System showed the nearest point of separation to be 400 FT. ATC advised us that conflict aircraft was 'not supposed to be there' and was apparently not in contact with them.

Data retrieved from NASA's ASRS site as of July 2013 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.

B737-700 experienced near midair collision on downwind at lax from an aircraft who was not talking to ATC.