Narrative:

Iad-atl. Flight was being vectored for a fairly short approach on base leg to runway 8L, descending to 3500 ft MSL and slowing to 170 KTS. TCASII alerted 'traffic' and 'off-scale traffic' displayed on captain's navigation display. Atl approach called traffic, but information was not initially understood by crew, as we were expecting the turn to final and ATC to call the traffic on final. A TCASII RA 'monitor vertical speed' occurred and traffic was visually observed overshooting the base to final turn to runway 9R. The autoplt was disconnected, the descent was reduced, and a turn toward final was initiated. Approach control instructed us to maintain visual separation and cleared us for the visual approach. We continued to descend approaching the final approach course, but were now high. The aircraft was configured for a flaps 40 degree landing, but in this high workload environment, the command speed bug was set incorrectly at vref. The error was corrected and vref +5 KTS was set at a low altitude. The approach was stabilized by 500 ft AGL, and a normal landing was made.

Google
 

Original NASA ASRS Text

Title: AN INITIALLY DESTABILIZED APCH CREATED BY A TFC CONFLICT IS CORRECTED BY AN OVERWORKED B737-800 FLC AFTER AVOIDING OTHER TFC ON AN OVERSHOOT TO FINAL AT ATL, GA.

Narrative: IAD-ATL. FLT WAS BEING VECTORED FOR A FAIRLY SHORT APCH ON BASE LEG TO RWY 8L, DSNDING TO 3500 FT MSL AND SLOWING TO 170 KTS. TCASII ALERTED 'TFC' AND 'OFF-SCALE TFC' DISPLAYED ON CAPT'S NAV DISPLAY. ATL APCH CALLED TFC, BUT INFO WAS NOT INITIALLY UNDERSTOOD BY CREW, AS WE WERE EXPECTING THE TURN TO FINAL AND ATC TO CALL THE TFC ON FINAL. A TCASII RA 'MONITOR VERT SPD' OCCURRED AND TFC WAS VISUALLY OBSERVED OVERSHOOTING THE BASE TO FINAL TURN TO RWY 9R. THE AUTOPLT WAS DISCONNECTED, THE DSCNT WAS REDUCED, AND A TURN TOWARD FINAL WAS INITIATED. APCH CTL INSTRUCTED US TO MAINTAIN VISUAL SEPARATION AND CLRED US FOR THE VISUAL APCH. WE CONTINUED TO DSND APCHING THE FINAL APCH COURSE, BUT WERE NOW HIGH. THE ACFT WAS CONFIGURED FOR A FLAPS 40 DEG LNDG, BUT IN THIS HIGH WORKLOAD ENVIRONMENT, THE COMMAND SPD BUG WAS SET INCORRECTLY AT VREF. THE ERROR WAS CORRECTED AND VREF +5 KTS WAS SET AT A LOW ALT. THE APCH WAS STABILIZED BY 500 FT AGL, AND A NORMAL LNDG WAS MADE.

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.