Narrative:

While in level flight at 5;000 ft over ocn VOR; socal approach told us we had an aircraft at 4;500 ft at our 12 o'clock. ATC also told us to maintain 5;000 ft. I replied that we were looking for the traffic and that we had the aircraft on TCAS. As we approached the traffic we were unable to gain a visual on the aircraft and I noticed the aircraft was deviating from 4;500 to 4;800 ft. I told my first officer who was flying to be ready for a deviation or climb; shortly after I said that we got an RA with a climb command. My first officer turned off the autopilot and began a climb to comply with the RA climb. My first officer climbed to 6;000 ft. To avoid the climbing traffic. As soon as my first officer started the climb I notified ATC that we were climbing and the TCAS was saying 'climb; climb' in the background on top of my transmission socal approach then asked us to return to 5;000 ft and I replied that we were. Right before I said we were returning to 5;000 ft the TCAS said 'clear of conflict'. My first officer then returned the aircraft to 5;000 ft. No other aircraft were impacted during the deviation and the controller began scolding the other traffic that caused the deviation. The socal controller told the other aircraft ' when I tell you to maintain an altitude because a jet is coming at you; you need to do it.' the other aircraft responded 'yes sir; we will.' after we returned to 5;000 ft that was the end of the event and we landed without further incident.

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Original NASA ASRS Text

Title: A corporate jet Captain reported an NMAC with a light aircraft in SoCal airspace.

Narrative: While in level flight at 5;000 FT over OCN VOR; SoCal approach told us we had an aircraft at 4;500 FT at our 12 o'clock. ATC also told us to maintain 5;000 FT. I replied that we were looking for the traffic and that we had the aircraft on TCAS. As we approached the traffic we were unable to gain a visual on the aircraft and I noticed the aircraft was deviating from 4;500 to 4;800 FT. I told my First Officer who was flying to be ready for a deviation or climb; shortly after I said that we got an RA with a climb command. My First Officer turned off the autopilot and began a climb to comply with the RA climb. My First Officer climbed to 6;000 FT. to avoid the climbing traffic. As soon as my First Officer started the climb I notified ATC that we were climbing and the TCAS was saying 'climb; climb' in the background on top of my transmission SoCal approach then asked us to return to 5;000 FT and I replied that we were. Right before I said we were returning to 5;000 FT the TCAS said 'Clear of conflict'. My First Officer then returned the aircraft to 5;000 FT. No other aircraft were impacted during the deviation and the controller began scolding the other traffic that caused the deviation. The SoCal controller told the other aircraft ' When I tell you to maintain an altitude because a jet is coming at you; you need to do it.' The other aircraft responded 'Yes sir; we will.' After we returned to 5;000 FT that was the end of the event and we landed without further incident.

Data retrieved from NASA's ASRS site as of April 2012 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.