Narrative:

We were descending into sacramento metropolitan on the wraps 5 arrival. We had just crossed twane intersection at 11000 ft as directed by ATC. The copilot was flying and had just changed his navigation radio from linden VOR to sacramento VOR to proceed inbound. I was still on linden VOR. At that moment I noticed traffic on the TCASII at 1 O'clock to 1:30, 1000 ft below us and climbing. Almost immediately we received a TA from the TCASII. Very shortly thereafter we received an RA from TCASII directing a climb avoidance maneuver. We immediately started a climb. At the moment we started the climb, oakland center called and asked us to turn left direct to the sacramento VOR and resume the wraps 5 arrival. We advised them that we were presently in a climb to avoid traffic and would comply. At about 11600 ft TCASII signaled 'clear of conflict.' we stopped climb at 11700 ft and descended back to 11000 ft. Oakland center then asked us if we were previously cleared for the wraps 5, and we said yes. Center said that we were about 4 mi right of course and should proceed direct to the sacramento VOR and resume the wraps 5. We were then handed off to sacramento approach and proceeded to the airport. We are unable to reconcile the difference between where we thought we were on the arrival and the position reported by ATC. The TCASII maneuver occupied our attention at the time and we were not able to xchk our position until we had descended back to 11000 ft, and the turn requested by ATC had changed our position some, but when I changed from linden VOR to sacramento VOR to go direct, we were very close to the proper 113 degree radial inbound. It is possible that we departed linden VOR on the 304 degree inbound course rather than changing to the 294 degree outbound radial, however, the subsequent events caused us to change the courses set in our instruments, and we cannot be positive of our linden outbound course. We were subsequently (after pushback for our next leg) asked to contact sacramento TRACON by telephone. During that conversation we were advised that our TCASII avoidance maneuver had taken us into conflict with other traffic in the vicinity, and that a TCASII transition program form was being filed, as well as an incident report due to the traffic conflict it caused. Concerning avoidance of such a situation in the future, it is our standard operating procedure to verbally xchk route radials as they are set at each inbound and outbound change, and at linden VOR this xchk did not take place. This omission increased our exposure to the possibility of a navigation error.

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Original NASA ASRS Text

Title: ACR LGT TRACK HDG DEV ON STAR INTO SMF. TCASII ALSO CAUSED AND ALTDEV EXCURSION FROM CLRNC ALT.

Narrative: WE WERE DSNDING INTO SACRAMENTO METRO ON THE WRAPS 5 ARR. WE HAD JUST CROSSED TWANE INTXN AT 11000 FT AS DIRECTED BY ATC. THE COPLT WAS FLYING AND HAD JUST CHANGED HIS NAV RADIO FROM LINDEN VOR TO SACRAMENTO VOR TO PROCEED INBOUND. I WAS STILL ON LINDEN VOR. AT THAT MOMENT I NOTICED TFC ON THE TCASII AT 1 O'CLOCK TO 1:30, 1000 FT BELOW US AND CLBING. ALMOST IMMEDIATELY WE RECEIVED A TA FROM THE TCASII. VERY SHORTLY THEREAFTER WE RECEIVED AN RA FROM TCASII DIRECTING A CLB AVOIDANCE MANEUVER. WE IMMEDIATELY STARTED A CLB. AT THE MOMENT WE STARTED THE CLB, OAKLAND CENTER CALLED AND ASKED US TO TURN L DIRECT TO THE SACRAMENTO VOR AND RESUME THE WRAPS 5 ARR. WE ADVISED THEM THAT WE WERE PRESENTLY IN A CLB TO AVOID TFC AND WOULD COMPLY. AT ABOUT 11600 FT TCASII SIGNALED 'CLR OF CONFLICT.' WE STOPPED CLB AT 11700 FT AND DSNDED BACK TO 11000 FT. OAKLAND CENTER THEN ASKED US IF WE WERE PREVIOUSLY CLRED FOR THE WRAPS 5, AND WE SAID YES. CENTER SAID THAT WE WERE ABOUT 4 MI R OF COURSE AND SHOULD PROCEED DIRECT TO THE SACRAMENTO VOR AND RESUME THE WRAPS 5. WE WERE THEN HANDED OFF TO SACRAMENTO APCH AND PROCEEDED TO THE ARPT. WE ARE UNABLE TO RECONCILE THE DIFFERENCE BTWN WHERE WE THOUGHT WE WERE ON THE ARR AND THE POS RPTED BY ATC. THE TCASII MANEUVER OCCUPIED OUR ATTN AT THE TIME AND WE WERE NOT ABLE TO XCHK OUR POS UNTIL WE HAD DSNDED BACK TO 11000 FT, AND THE TURN REQUESTED BY ATC HAD CHANGED OUR POS SOME, BUT WHEN I CHANGED FROM LINDEN VOR TO SACRAMENTO VOR TO GO DIRECT, WE WERE VERY CLOSE TO THE PROPER 113 DEG RADIAL INBOUND. IT IS POSSIBLE THAT WE DEPARTED LINDEN VOR ON THE 304 DEG INBOUND COURSE RATHER THAN CHANGING TO THE 294 DEG OUTBOUND RADIAL, HOWEVER, THE SUBSEQUENT EVENTS CAUSED US TO CHANGE THE COURSES SET IN OUR INSTS, AND WE CANNOT BE POSITIVE OF OUR LINDEN OUTBOUND COURSE. WE WERE SUBSEQUENTLY (AFTER PUSHBACK FOR OUR NEXT LEG) ASKED TO CONTACT SACRAMENTO TRACON BY TELEPHONE. DURING THAT CONVERSATION WE WERE ADVISED THAT OUR TCASII AVOIDANCE MANEUVER HAD TAKEN US INTO CONFLICT WITH OTHER TFC IN THE VICINITY, AND THAT A TCASII TRANSITION PROGRAM FORM WAS BEING FILED, AS WELL AS AN INCIDENT RPT DUE TO THE TFC CONFLICT IT CAUSED. CONCERNING AVOIDANCE OF SUCH A SITUATION IN THE FUTURE, IT IS OUR STANDARD OPERATING PROC TO VERBALLY XCHK RTE RADIALS AS THEY ARE SET AT EACH INBOUND AND OUTBOUND CHANGE, AND AT LINDEN VOR THIS XCHK DID NOT TAKE PLACE. THIS OMISSION INCREASED OUR EXPOSURE TO THE POSSIBILITY OF A NAV ERROR.

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.