Narrative:

The evasive action taken was in response to a TCASII RA following takeoff from ont, we were proceeding direct paradise VOR at 7000 ft. We were in level flight with the autoplt on. The captain was flying, and had transferred aircraft control to me. There appeared to be a lot of traffic in the ont area. We noted many TCASII targets on our radar screen from takeoff through this event. In addition to directing traffic, the controller was very busy pointing out traffic to various aircraft. The controller was also kept busy for a few moments while a GA aircraft listed all of the practice approachs he would like at a couple of area airports. The TCASII issued an RA saying 'monitor vertical speed.' a red arc was displayed on our vvi showing do not descend -- so we stayed level at 7000 ft. This was followed very shortly after by an RA saying 'climb' and commanding a climb of 2500 FPM. I disconnected the autoplt and initiated a climb of 2500 FPM. The captain immediately called ATC and told him we were deviating in response to a TCASII alert. We climbed to approximately 7500 ft, the RA ceased, and we returned to 7000 ft. The controller asked our altitude, and we again told him we had deviated for a TCASII RA. The controller also asked if we saw an aircraft in front of us at 8000 ft. We replied negative. Neither the aircraft at 8000 ft or the aircraft that caused the RA was ever sighted. We followed our company's procedures in response to the RA's, but it would appear that in a congested area, one of the short comings of the TCASII system is that by responding to one potential conflict, you may be put in another similar or worse conflict. Supplemental information from acn 200166. There were numerous calls from the controller to a number of aircraft concerning traffic. We were advised of traffic at 8000. I told the controller by radio, but apparently the call was blocked or he never heard it, as the frequency was congested.

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Original NASA ASRS Text

Title: ACR MLG ALTDEV EXCURSION FROM CLRNC ALT IN RESPONSE TO TCASII RA ON AN ONT SID.

Narrative: THE EVASIVE ACTION TAKEN WAS IN RESPONSE TO A TCASII RA FOLLOWING TKOF FROM ONT, WE WERE PROCEEDING DIRECT PARADISE VOR AT 7000 FT. WE WERE IN LEVEL FLT WITH THE AUTOPLT ON. THE CAPT WAS FLYING, AND HAD TRANSFERRED ACFT CTL TO ME. THERE APPEARED TO BE A LOT OF TFC IN THE ONT AREA. WE NOTED MANY TCASII TARGETS ON OUR RADAR SCREEN FROM TKOF THROUGH THIS EVENT. IN ADDITION TO DIRECTING TFC, THE CTLR WAS VERY BUSY POINTING OUT TFC TO VARIOUS ACFT. THE CTLR WAS ALSO KEPT BUSY FOR A FEW MOMENTS WHILE A GA ACFT LISTED ALL OF THE PRACTICE APCHS HE WOULD LIKE AT A COUPLE OF AREA ARPTS. THE TCASII Issued AN RA SAYING 'MONITOR VERT SPD.' A RED ARC WAS DISPLAYED ON OUR VVI SHOWING DO NOT DSND -- SO WE STAYED LEVEL AT 7000 FT. THIS WAS FOLLOWED VERY SHORTLY AFTER BY AN RA SAYING 'CLB' AND COMMANDING A CLB OF 2500 FPM. I DISCONNECTED THE AUTOPLT AND INITIATED A CLB OF 2500 FPM. THE CAPT IMMEDIATELY CALLED ATC AND TOLD HIM WE WERE DEVIATING IN RESPONSE TO A TCASII ALERT. WE CLBED TO APPROX 7500 FT, THE RA CEASED, AND WE RETURNED TO 7000 FT. THE CTLR ASKED OUR ALT, AND WE AGAIN TOLD HIM WE HAD DEVIATED FOR A TCASII RA. THE CTLR ALSO ASKED IF WE SAW AN ACFT IN FRONT OF US AT 8000 FT. WE REPLIED NEGATIVE. NEITHER THE ACFT AT 8000 FT OR THE ACFT THAT CAUSED THE RA WAS EVER SIGHTED. WE FOLLOWED OUR COMPANY'S PROCS IN RESPONSE TO THE RA'S, BUT IT WOULD APPEAR THAT IN A CONGESTED AREA, ONE OF THE SHORT COMINGS OF THE TCASII SYS IS THAT BY RESPONDING TO ONE POTENTIAL CONFLICT, YOU MAY BE PUT IN ANOTHER SIMILAR OR WORSE CONFLICT. SUPPLEMENTAL INFO FROM ACN 200166. THERE WERE NUMEROUS CALLS FROM THE CTLR TO A NUMBER OF ACFT CONCERNING TFC. WE WERE ADVISED OF TFC AT 8000. I TOLD THE CTLR BY RADIO, BUT APPARENTLY THE CALL WAS BLOCKED OR HE NEVER HEARD IT, AS THE FREQ WAS CONGESTED.

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.