Narrative:

While climbing to our initial assigned altitude of 5000 ft we were handed off to ZOA. We contacted center and we were immediately acknowledged and told to climb to 7000 ft. Seconds after the communication we received a traffic descend command from the TCAS. I cut power and began to descend. I then saw the aircraft in a position where a collision was imminent. Further correction was required to avoid the collision. When we advised control that we were responding to an RA we were simply told; yes there is bonanza traffic at 3200 ft. We were never told about the traffic prior to takeoff nor during check in while being assigned a higher altitude. It appears that ATC knew of the traffic but did not advise until after we stated that we were initiating evasive action.

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Original NASA ASRS Text

Title: IFR LR-45 CLIMBING WITH ZOA EXPERIENCED TCAS RA AT APPROX 5000; INDICATING ATC KNEW OF THE TFC BUT DID NOT ISSUE ADVISORY.

Narrative: WHILE CLBING TO OUR INITIAL ASSIGNED ALT OF 5000 FT WE WERE HANDED OFF TO ZOA. WE CONTACTED CTR AND WE WERE IMMEDIATELY ACKNOWLEDGED AND TOLD TO CLB TO 7000 FT. SECONDS AFTER THE COM WE RECEIVED A TFC DSND COMMAND FROM THE TCAS. I CUT PWR AND BEGAN TO DSND. I THEN SAW THE ACFT IN A POS WHERE A COLLISION WAS IMMINENT. FURTHER CORRECTION WAS REQUIRED TO AVOID THE COLLISION. WHEN WE ADVISED CTL THAT WE WERE RESPONDING TO AN RA WE WERE SIMPLY TOLD; YES THERE IS BONANZA TFC AT 3200 FT. WE WERE NEVER TOLD ABOUT THE TFC PRIOR TO TKOF NOR DURING CHK IN WHILE BEING ASSIGNED A HIGHER ALT. IT APPEARS THAT ATC KNEW OF THE TFC BUT DID NOT ADVISE UNTIL AFTER WE STATED THAT WE WERE INITIATING EVASIVE ACTION.

Data retrieved from NASA's ASRS site as of May 2009 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.