Narrative:

On approach control frequency, cleared for visual approach runway 14 anc, follow medium large transport traffic ahead. Told to switch to tower frequency. Tower cleared us to land #2 behind medium large transport and asked us to 'square your turn to final for 1 departure.' I intentionally overshot the extended runway centerline slightly turning base to final to build a little more ground track distance into my approach. While in the turn to final we received a TCASII TA and idented an aircraft ahead and below maneuvering well to the left of the extended runway centerline. We received an RA on the same target and TCASII instructed us to climb at 1500 FPM. I announced to the other 2 crew members that I had the target in sight and that I believed he wouldn't' be a factor and that I would disregard the RA as a spurious alert. In fact, TCASII was telling the truth. As we were turning final our conflicting traffic was turning to pick up a track that would cross the approach end of the runway from left to right and, almost instantly, our TCASII RA increased intensity to 'increase climb' to 2500 FPM. I announced that I was going around and immediately increased thrust and pitched up to a climb attitude. I felt that the safest thing to do was to arrest our descent, begin a shallow climb, clear the airspace to the right and begin a shallow turn to the right. (I could keep the intruder in sight at all times.) I told the first officer to announce our go around. The first transmission from the tower regarding the intruder came at the moment I began the evasive maneuver and before the first officer could transmit our intentions. Tower basically cautioned us about the intruder but we were already beginning the go around. Tower gave us a heading and altitude and a handoff to departure. We were sequenced in behind another arrival and subsequent approach landing normal. Upon arrival I called the tower and spoke with the supervisor who filled me in on the details of the intruder. It was a NOAA twin flying along the shoreline at 800 ft MSL looking for whales. The twin was talking to approach control. He had approval to cross the final approach course of the only landing runway at an international airport between landing traffic. The supervisor was surprised that I was not advised of this twin and his intentions, either by approach control before the handoff or by the local controller when landing clearance was given. He stated that there may have been a breakdown in communication between tower and approach. Because I stayed high on profile I increased my workload by having to monitor a higher than normal sink rate. I was reluctant to transition from high drag descent to a 1500 FPM rate of climb and, when my inaction and the intruder's course change resulted in an enhanced RA, I was unable to meet the performance required. Trying to create more separation for 1 departure also increased our workload. I should have taken the airplane around, straight ahead, on the first RA. We were not advised of the twin traffic while on approach frequency and not until we began our go around on tower frequency. We all perceived the intruder as unannounced, unwelcomed. Somehow, I find the thought that the controllers simply failed to advise us of a critical traffic situation as unbelievable. I am more inclined to believe that the advisory was given and we did not comprehend it. Even without a timely advisory from ATC, I still have plenty of ways of not letting surprise traffic conflicts get me painted into a corner. Keeping more nearly on profile, watching spacing closely and asking tower about questionable traffic, and finally, taking TCASII at its word.

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Original NASA ASRS Text

Title: POTENTIAL CONFLICT ON FINAL APCH BTWN ACR LGT AND TWIN LTT LOOKING FOR WHALES.

Narrative: ON APCH CTL FREQ, CLRED FOR VISUAL APCH RWY 14 ANC, FOLLOW MLG TFC AHEAD. TOLD TO SWITCH TO TWR FREQ. TWR CLRED US TO LAND #2 BEHIND MLG AND ASKED US TO 'SQUARE YOUR TURN TO FINAL FOR 1 DEP.' I INTENTIONALLY OVERSHOT THE EXTENDED RWY CTRLINE SLIGHTLY TURNING BASE TO FINAL TO BUILD A LITTLE MORE GND TRACK DISTANCE INTO MY APCH. WHILE IN THE TURN TO FINAL WE RECEIVED A TCASII TA AND IDENTED AN ACFT AHEAD AND BELOW MANEUVERING WELL TO THE L OF THE EXTENDED RWY CTRLINE. WE RECEIVED AN RA ON THE SAME TARGET AND TCASII INSTRUCTED US TO CLB AT 1500 FPM. I ANNOUNCED TO THE OTHER 2 CREW MEMBERS THAT I HAD THE TARGET IN SIGHT AND THAT I BELIEVED HE WOULDN'T' BE A FACTOR AND THAT I WOULD DISREGARD THE RA AS A SPURIOUS ALERT. IN FACT, TCASII WAS TELLING THE TRUTH. AS WE WERE TURNING FINAL OUR CONFLICTING TFC WAS TURNING TO PICK UP A TRACK THAT WOULD CROSS THE APCH END OF THE RWY FROM L TO R AND, ALMOST INSTANTLY, OUR TCASII RA INCREASED INTENSITY TO 'INCREASE CLB' TO 2500 FPM. I ANNOUNCED THAT I WAS GOING AROUND AND IMMEDIATELY INCREASED THRUST AND PITCHED UP TO A CLB ATTITUDE. I FELT THAT THE SAFEST THING TO DO WAS TO ARREST OUR DSCNT, BEGIN A SHALLOW CLB, CLR THE AIRSPACE TO THE R AND BEGIN A SHALLOW TURN TO THE R. (I COULD KEEP THE INTRUDER IN SIGHT AT ALL TIMES.) I TOLD THE FO TO ANNOUNCE OUR GAR. THE FIRST XMISSION FROM THE TWR REGARDING THE INTRUDER CAME AT THE MOMENT I BEGAN THE EVASIVE MANEUVER AND BEFORE THE FO COULD XMIT OUR INTENTIONS. TWR BASICALLY CAUTIONED US ABOUT THE INTRUDER BUT WE WERE ALREADY BEGINNING THE GAR. TWR GAVE US A HDG AND ALT AND A HDOF TO DEP. WE WERE SEQUENCED IN BEHIND ANOTHER ARR AND SUBSEQUENT APCH LNDG NORMAL. UPON ARR I CALLED THE TWR AND SPOKE WITH THE SUPVR WHO FILLED ME IN ON THE DETAILS OF THE INTRUDER. IT WAS A NOAA TWIN FLYING ALONG THE SHORELINE AT 800 FT MSL LOOKING FOR WHALES. THE TWIN WAS TALKING TO APCH CTL. HE HAD APPROVAL TO CROSS THE FINAL APCH COURSE OF THE ONLY LNDG RWY AT AN INTL ARPT BTWN LNDG TFC. THE SUPVR WAS SURPRISED THAT I WAS NOT ADVISED OF THIS TWIN AND HIS INTENTIONS, EITHER BY APCH CTL BEFORE THE HDOF OR BY THE LCL CTLR WHEN LNDG CLRNC WAS GIVEN. HE STATED THAT THERE MAY HAVE BEEN A BREAKDOWN IN COM BTWN TWR AND APCH. BECAUSE I STAYED HIGH ON PROFILE I INCREASED MY WORKLOAD BY HAVING TO MONITOR A HIGHER THAN NORMAL SINK RATE. I WAS RELUCTANT TO TRANSITION FROM HIGH DRAG DSCNT TO A 1500 FPM RATE OF CLB AND, WHEN MY INACTION AND THE INTRUDER'S COURSE CHANGE RESULTED IN AN ENHANCED RA, I WAS UNABLE TO MEET THE PERFORMANCE REQUIRED. TRYING TO CREATE MORE SEPARATION FOR 1 DEP ALSO INCREASED OUR WORKLOAD. I SHOULD HAVE TAKEN THE AIRPLANE AROUND, STRAIGHT AHEAD, ON THE FIRST RA. WE WERE NOT ADVISED OF THE TWIN TFC WHILE ON APCH FREQ AND NOT UNTIL WE BEGAN OUR GAR ON TWR FREQ. WE ALL PERCEIVED THE INTRUDER AS UNANNOUNCED, UNWELCOMED. SOMEHOW, I FIND THE THOUGHT THAT THE CTLRS SIMPLY FAILED TO ADVISE US OF A CRITICAL TFC SIT AS UNBELIEVABLE. I AM MORE INCLINED TO BELIEVE THAT THE ADVISORY WAS GIVEN AND WE DID NOT COMPREHEND IT. EVEN WITHOUT A TIMELY ADVISORY FROM ATC, I STILL HAVE PLENTY OF WAYS OF NOT LETTING SURPRISE TFC CONFLICTS GET ME PAINTED INTO A CORNER. KEEPING MORE NEARLY ON PROFILE, WATCHING SPACING CLOSELY AND ASKING TWR ABOUT QUESTIONABLE TFC, AND FINALLY, TAKING TCASII AT ITS WORD.

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.